Forecasting the spread of COVID-19 based on policy, vaccination, and Omicron data

The COVID-19 pandemic caused by the novel SARS-COV-2 virus poses a great risk to the world. During the COVID-19 pandemic, observing and forecasting several important indicators of the epidemic (like new confirmed cases, new cases in intensive care unit, and new deaths for each day) helped prepare the appropriate response (e.g., creating additional intensive care unit beds, and implementing strict interventions). Various predictive models and predictor variables have been used to forecast these indicators. However, the impact of prediction models and predictor variables on forecasting performance has not been systematically well analyzed. Here, we compared the forecasting performance using a linear mixed model in terms of prediction models (mathematical, statistical, and AI/machine learning models) and predictor variables (vaccination rate, stringency index, and Omicron variant rate) for seven selected countries with the highest vaccination rates. We decided on our best models based on the Bayesian Information Criterion (BIC) and analyzed the significance of each predictor. Simple models were preferred. The selection of the best prediction models and the use of Omicron variant rate were considered essential in improving prediction accuracies. For the test data period before Omicron variant emergence, the selection of the best models was the most significant factor in improving prediction accuracy. For the test period after Omicron emergence, Omicron variant rate use was considered essential in deciding forecasting accuracy. For prediction models, ARIMA, lightGBM, and TSGLM generally performed well in both test periods. Linear mixed models with country as a random effect has proven that the choice of prediction models and the use of Omicron data was significant in determining forecasting accuracies for the highly vaccinated countries. Relatively simple models, fit with either prediction model or Omicron data, produced best results in enhancing forecasting accuracies with test data.

COVID-19 vaccine uptake among non-US-born populations in the United States, 2020-2022

BACKGROUND

In the United States (US), COVID-19 vaccination rates among non-US-born individuals (i.e., refugees, immigrants, and migrants [RIM]) are variable. Understanding baseline COVID-19 vaccine coverage among these populations and determining if disparities exist is essential for quality improvement initiatives and public health interventions.

METHODS

Baseline COVID-19 vaccination rates for both primary series and booster doses were calculated at four health systems located in Minnesota, Colorado, and Pennsylvania participating in the Minnesota Department of Health's Center of Excellence in Newcomer Health. Patients aged ≥5 years as of 1/1/22, seen for ≥1 primary care visit during 7/1/2019-6/30/22 were included. Descriptive statistics were calculated for three measures of COVID-19 vaccine coverage during 12/14/2020-6/30/2022: 1) initiation of primary series; 2) completion of primary series; 3) completion of first booster. We calculated vaccine coverage rates for the entire population and stratified by subgroup including country of origin, refugee status, and primary language preference.

RESULTS

We included 1,624,573 patients eligible for COVID-19 primary series vaccine and 907,749 eligible for COVID-19 booster vaccination. The percent of eligible patients who completed a COVID-19 primary series (63.4 %) and booster dose (66.2 %) were similar. Completion of the primary series was higher for non-US-born persons (72.7 %) compared with US born persons (65.4 %), similar among refugees (63.5 %) and non-refugees (63.4 %), and lower in patients with language preference other than English (62.7 %) compared with English preferring patients (63.6 %). Booster completion was lower for non-US-born persons (61.8 %), refugees (46.7 %), and patients with language preference other than English (55.3 %) compared with US-born (70 %), non-refugees (66.3 %), and English preferring patients (67.3 %) respectively.

CONCLUSIONS

This evaluation identified disparities in COVID-19 vaccination rates among non-US-born persons and persons with a language preference other than English living in the US. Targeted outreach efforts may be beneficial in reaching these populations.

Despite mandated primary series, health care personnel still hesitant about COVID-19 vaccine and immunizing children

IMPORTANCE

Healthcare personnel (HCP) are important messengers for promoting vaccines, for both adults and children. Our investigation describes perceptions of fully vaccinated HCP about COVID-19 vaccine for themselves and primary series for their children.

OBJECTIVE

To determine associations between sociodemographic, employment characteristics and perceptions of COVID-19 vaccines among HCP overall and the subset of HCP with children, who were all mandated to receive a COVID-19 vaccine, in a large US metropolitan region.

DESIGN

Cross-sectional survey of fully vaccinated HCP from a large integrated health system.

SETTING

Participants were electronically enrolled within a multi-site NYS healthcare system from December 21, 2021, to January 21, 2022.

PARTICIPANTS

Of 78,000 employees, approximately one-third accessed promotional emails; 6,537 employees started surveys and 4165 completed them. Immunocompromised HCP (self-reported) were excluded.

EXPOSURE(S) (FOR OBSERVATIONAL STUDIES)

We conducted a survey with measures including demographic variables, employment history, booster status, child vaccination status; vaccine recommendation, confidence, and knowledge.

MAIN OUTCOME(S) AND MEASURES

The primary outcome was COVID-19 vaccine hesitancy for all dose types - primary series or booster doses - among HCP.

RESULTS

Findings from 4,165 completed surveys indicated that almost 17.2 % of all HCP, including administrative and clinical staff, were hesitant or unsure about receiving a COVID-19 vaccine booster, despite the NYS recommendation to do so. Depending on age group, between 20 % and 40 % of HCP were hesitant about having their children vaccinated for COVID-19, regardless of clinical versus non-clinical duties. In multivariable regression analyses, lack of booster dose, unvaccinated children, females, income less than $50,000, and residence in Manhattan remained significantly associated with vaccine hesitancy.

CONCLUSIONS AND RELEVANCE

Despite mandated COVID-19 vaccination, a substantial proportion of HCP remained vaccine hesitant towards adult booster doses and pediatric COVID-19 vaccination. While provider recommendation has been the mainstay of combatting COVID-19 vaccine hesitancy, a gap exists between HCP-despite clinical or administrative status-and the ability to communicate the need for vaccination in a healthcare setting. While previous studies describe the HCP vaccine mandate as a positive force to overcome vaccine hesitancy, we have found that despite a mandate, there is still substantial COVID-19 vaccine hesitancy, misinformation, and reluctance to vaccinate children.

Self-reported determinants of COVID-19 vaccine acceptance among persons with and without autoimmune disease

OBJECTIVE

Patients with autoimmune disease (AD) are at increased risk for complications from COVID-19 infection, so, optimizing vaccine utilization in this population is of particular importance. We compared COVID-19 vaccination perspectives among persons with and without AD.

METHODS

471 patients in the MetroHealth System and Cleveland Veteran Affairs Medical Center completed a 38-item questionnaire between August 2021 and February 2022. This survey containing questions regarding COVID-19 vaccine perceptions and demographics was administered both to unvaccinated individuals and individuals who delayed vaccination for at least 2 months. Multivariable ordinary least squares regression models were created to assess factors associated with vaccination likelihood.

RESULTS

The number of reasons given for (p < 0.001) and against receiving COVID-19 vaccination (p < 0.001) were highly associated with increased and decreased vaccination likelihood respectively. Factors most closely associated with obtaining vaccine were: protecting family (p = 0.045) personal safety (p < 0.001) and preventing serious infection (p < 0.001). Reasons associated with decreased vaccination likelihood were: lack of concern of COVID-19 infection (p < 0.001), vaccine safety (p < 0.001) and beliefs that the vaccine was made too quickly (p = 0.024). AD patients were more likely to cite having a chronic condition (29.1 % vs 17.1 %, p = 0.003) and physician recommendation(s) (18.4 % vs 9.1 %, p = 0.005) as reasons for vaccination and were more concerned about potential medication interaction than non-AD respondents (22.4 % vs 3.3 %, p < 0.001).

CONCLUSION

The number of benefits of vaccination identified strongly related to vaccination likelihood. Affirmative provider recommendations correlated with increased vaccination likelihood in AD patients. Clinical conversations centered on the benefits of COVID-19 vaccination may help increase vaccine acceptance.

Cost-effectiveness of an in-development adult-formulated 21-valent pneumococcal conjugate vaccine in US adults aged 50 years or older

Indirect effects of childhood pneumococcal conjugate vaccines (PCV) have diminished the cost-effectiveness of current adult vaccine recommendations. An in-development adult-formulated 21-valent pneumococcal conjugate vaccine (PCV21) may play a critical role in reducing pneumococcal illness by targeting a larger number of serotypes responsible for adult pneumococcal infections. This study assesses the cost-effectiveness of PCV21 in US adults aged 50 years or older compared with currently recommended pneumococcal vaccines, from both the societal and healthcare perspectives. A Markov model evaluated the lifetime cost-effectiveness of PCV21 (given at age 50 years only, at ages 50/65 years, and risk-based at ages < 65 years plus age-based at age 65 years) compared to no vaccination and to currently recommended pneumococcal vaccines given either as currently recommended or routinely at ages 50/65 years. The analysis was conducted in hypothetical Black and non-Black cohorts aged 50 years or older, with and without considering childhood pneumococcal vaccination indirect effects. Model parameters were based on US data. Parameter uncertainty was assessed using 1-way and probabilistic sensitivity analyses. From the societal perspective, PCV21 at ages 50/65 years compared to PCV21 at age 50 years cost $7,410 per quality adjusted life year (QALY) gained in Black cohort analyses and $85,696/QALY gained in the non-Black cohort; PCV21 at ages 50/65 years had the most favorable public health outcomes. From the healthcare perspective, compared to no vaccination, PCV21 at age 50 years cost $46,213/QALY gained in the Black cohort and $86,629/QALY in non-Blacks. All other strategies were dominated in both cohorts and from both perspectives. When considering childhood pneumococcal vaccination indirect effects, costs of PCV21 at ages 50/65 years remained less than $140,000/QALY gained from the societal perspective in both populations. PCV21 is potentially cost-effective compared to currently approved pneumococcal vaccines in adults aged 50 years or older from both the societal and healthcare perspectives.

Reliance on sources of immunization information and vaccine uptake among older adults in a rural state: The mediating role of trust

Older adults are more vulnerable to the negative impacts of infectious diseases than younger individuals. However, regardless of the importance and effectiveness of vaccines to reduce morbidity and mortality, issues remain with vaccine hesitancy among this population. Older adults' sources of immunization information and their level of trust in those sources may play a role in their vaccination behaviors. This research aimed to better understand the role of information sources and related issues of trust as related to vaccine uptake among older adults. A community-based, cross-sectional survey was conducted with 901 older adults in North Dakota in May-July 2022. Measures included extent of reliance on specific sources of immunization information, levels of trust, and uptake for influenza, pneumonia, shingles, and COVID-19 vaccinations. Immunization information sources were grouped into medical experts, informal, and public outlets. Results indicated older adults were more likely to rely on medical experts than informal sources or public outlets for immunization information. Greater reliance on medical experts was associated with a greater likelihood of vaccine uptake for all vaccines, while reliance on public outlets was associated with a greater likelihood of vaccine uptake only for COVID primary series and boosters. Reliance on informal sources for immunization information was associated with a reduced likelihood of vaccine uptake for all vaccines except shingles. Nearly half of respondents were uncertain who to trust for vaccine information. Uncertainty who to trust for immunization information significantly mediated the associations between reliance on medical experts and uptake for most vaccines indicating that trust in medical experts fosters vaccine uptake. Increasing reliance on medical experts as sources of immunization information is vital to increasing vaccine uptake among older adults. Additionally, this population must be assisted in increasing their ability to successfully assess the trustworthiness of immunization information sources.

Effects of BNT162b2 mRNA Covid-19 vaccine on vascular function

The effects of Covid-19 vaccines on vascular function are still controversial. We evaluated the effects of BNT162b2 vaccine (BioNTech and Pfizer) on endothelial function assessed by flow-mediated vasodilation (FMD) and vascular smooth muscle function assessed by nitroglycerine-induced vasodilation (NID). This study was a prospective observational study. A total of 23 medical staff at Hiroshima University Hospital were enrolled in this study. FMD and NID were measured before vaccination and two weeks and six months after the 2nd dose of vaccination. FMD was significantly smaller two weeks after the 2nd dose of vaccination than before vaccination (6.5±2.4% and 8.2±2.6%, p = 0.03). FMD was significantly larger at six months than at two weeks after the 2nd dose of vaccination (8.2±3.0% and 6.5±2.4%, p = 0.03). There was no significant difference between FMD before vaccination and that at six months after the 2nd dose of vaccination (8.2±2.6% to 8.2±3.0%, p = 0.96). NID values were similar before vaccination and at two weeks, and six months after vaccination (p = 0.89). The BNT162b2 Covid-19 vaccine temporally impaired endothelial function but not vascular smooth muscle function, and the impaired endothelial function returned to the baseline level within six months after vaccination.

Vaccine coverage among children born to immigrant parents in Norway, 2000-2020

BACKGROUND

The Norwegian Childhood Immunization Program maintains a high national coverage of 95-97% in the most recent years. Whether there are subgroups with lower uptake is less studied. This study examines pertussis and measles vaccination coverage among six immigrant groups in Norway. These vaccines are normally administered as part of different combination vaccines and their coverage rate indicate the national vaccination coverage against a range of additional infections.

METHODS

Data from the Norwegian National Population Register were linked at individual level with vaccination data from the Norwegian Immunisation Registry. The final sample consisted of 53,052 children born during 2000-2018 in Norway to parents who were born in Iraq, Lithuania, Pakistan, Poland, Somalia, or Vietnam. Vaccination coverage was measured at 2-years of age. Multivariate linear regression was utilized to estimate the relationship between vaccinations status, year of birth, gender, mother's length of residency in Norway, and area of residence.

RESULTS

At two years of age, the majority of the children were vaccinated. Coverage among the groups varied at, above, and below the national average for the two vaccines. For most of the years examined, children born by parents from Lithuania, Poland, and Somalia had lower coverage for the measles vaccine (range 81-84% in 2020) than the national level (97% in 2020). Children born by parents from the Eastern-European countries also had lower coverage than the national level for the pertussis vaccine (range 87-89% in 2020).

DISCUSSION

This study illustrates how subgroups with lower vaccination coverage may exists within a well-established vaccination program with high national coverages. Differences in coverage were found for both vaccines, but the differences were more pronounced for the measles vaccine. The high vaccination coverage in Norway provides indirect protection through herd immunity for unvaccinated individuals, however, the lower vaccination coverage in some immigrant groups is a concern.

The influence of neonatal BCG vaccination on in vitro cytokine responses to Plasmodium falciparum

BACKGROUND

Bacillus Calmette-Guérin (BCG) vaccination has off-target protective effects against infections unrelated to tuberculosis. Among these, murine and human studies suggest that BCG vaccination may protect against malaria. We investigated whether BCG vaccination influences neonatal in vitro cytokine responses to Plasmodium falciparum. Blood samples were collected from 108 participants in the Melbourne Infant Study BCG for Allergy and Infection Reduction (MIS BAIR) randomised controlled trial (Clinical trials registration NCT01906853, registered July 2013), seven days after randomisation to neonatal BCG (n = 66) or no BCG vaccination (BCG-naïve, n = 42). In vitro cytokine responses were measured following stimulation with P. falciparum-infected erythrocytes (PfIE) or E. coli.

RESULTS

No difference in the measured cytokines were observed between BCG-vaccinated and BCG-naïve neonates following stimulation with PfIE or E. coli. However, age at which blood was sampled was independently associated with altered cytokine responses to PfIE. Being male was also independently associated with increased TNF-a responses to both PfIE and E. coli.

CONCLUSION

These findings do not support a role for BCG vaccination in influencing in vitro neonatal cytokine responses to P. falciparum. Older neonates are more likely to develop P. falciparum-induced IFN-γ and IFN-γ-inducible chemokine responses implicated in early protection against malaria and malaria pathogenesis.

Perceptions, attitudes, and willingness of healthcare and frontline workers to participate in an Ebola vaccine trial in Uganda

BACKGROUND

Understanding the knowledge, perception and attitudes towards Ebola vaccines is an important factor in ensuring future use of these vaccines. A qualitative methods study embedded in an Ebola vaccine immunogenicity and safety trial (NCT04028349) was conducted to explore the knowledge and perceptions of healthcare (HCWs) and frontline workers (FLWs), about Ebola vaccines and their willingness to participate or recommend participation in Uganda.

METHOD

We carried out focus group discussions and semi-structured interviews before and after vaccination, with 70 HCWs and FLWs who consented to participate in the trial, and in the qualitative component, from August to September 2019. Data were analysed using thematic content analysis.

RESULTS

Respondents showed good knowledge about Ebola and the vaccines in general, and had wide access to information through several channels, including the study team. On prevention, particular attention was given to effective communication within health facilities. Misconceptions were mainly around route of transmission, animal origin and types of vaccines. Previous fears were based on rumours circulating in the community, mainly about the presence of the virus in the vaccine, side effects and intention to harm (e.g. by "the whites"), ultimately insisting on transparency, trust and involvement of local leaders. Acceptability of participation was motivated by the need to protect self and others, and the willingness to advance research. Majority were willing to recommend participation to their community.

CONCLUSIONS

Overall, information sharing leads to a better understanding and acceptance of vaccine trials and a positive vaccination experience can be a deciding factor in the acceptance of others. Particular attention should be paid to involving the community in addressing misconceptions and fears, while ensuring that participants have access to vaccination sites in terms of transport, and that they are properly accommodated at the study site including staying for a reasonable period of time.

Is vaccination against measles, mumps, and rubella associated with reduced rates of antibiotic treatments among children below the age of 2 years? Nationwide register-based study from Denmark, Finland, Norway, and Sweden

OBJECTIVES

Previous studies have shown that vaccination against measles, mumps, and rubella (MMR) may have beneficial non-specific effects, reducing the risk of infections not targeted by the vaccine. We investigated if MMR vaccine given after the third dose of diphtheria-tetanus-acellular pertussis vaccine (DTaP3), was associated with reduced rates of antibiotic treatments.

METHODS

Register-based cohort study following children from the age of recommended MMR vaccination until age 2 years. We included 831,287 children born in Denmark, Finland, Norway, and Sweden who had received DTaP3 but not yet MMR vaccine. Cox proportional hazards regression with age as the underlying timescale and vaccination status as a time-varying exposure was used to estimate covariate-adjusted Hazard Ratios (aHRs) and inverse probability of treatment weighted (IPTW) HRs of antibiotic treatments. Summary estimates were calculated using random-effects meta-analysis.

RESULTS

Compared with only having received DTaP3, receipt of MMR vaccine after DTaP3 was associated with reduced rates of antibiotic treatments in all countries: the aHR was 0.92 (0.91-0.93) in Denmark, 0.92 (0.90-0.94) in Finland, 0.84 (0.82-0.85) in Norway, and 0.87 (0.85-0.90) in Sweden, yielding a summary estimate of 0.89 (0.85-0.93). A stronger beneficial association was seen in a negative control exposure analysis comparing children vaccinated with DTaP3 vs two doses of DTaP.

CONCLUSIONS

Across the Nordic countries, receipt of MMR vaccine after DTaP3 was associated with an 11% lower rate of antibiotic treatments. The negative control analysis suggests that the findings are affected by residual confounding. Findings suggest that potential non-specific effects of MMR vaccine are of limited clinical and public health importance for the milder infections treated out-of-hospital in the Nordic setting.

Detection of SARS-CoV-2-specific mucosal antibodies in saliva following concomitant COVID-19 and influenza vaccination in the ComFluCOV trial

The ComFluCOV trial randomized 679 participants to receive an age-appropriate influenza vaccine, or placebo, alongside their second COVID-19 vaccine. Concomitant administration was shown to be safe, and to preserve systemic immune responses to both vaccines. Here we report on a secondary outcome of the trial investigating SARS-CoV-2-specific mucosal antibody responses. Anti-spike IgG and IgA levels in saliva were measured with in-house ELISAs. Concomitant administration of an influenza vaccine did not affect salivary anti-spike IgG positivity rates to Pfizer/BioNTech BNT162b2 (99.1 cf. 95.6%), or AstraZeneca ChAdOx1 (67.8% cf. 64.9%), at 3-weeks post-vaccination relative to placebo. Furthermore, saliva IgG positively correlated with serum titres highlighting the potential utility of saliva for assessing differences in immunogenicity in future vaccine studies. Mucosal IgA was not detected in response to either COVID-19 vaccine, reinforcing the need for novel vaccines capable of inducing sterilising immunity or otherwise reducing transmission. The trial is registered as ISRCTN 14391248.

Effectiveness of COVID-19 vaccination against school absenteeism in children and adolescents hospitalized with COVID-19

BACKGROUND

COVID-19 vaccination has been recommended for children to protect them and to enable in-person educational and social activities.

METHODS

We estimated COVID-19 vaccination effectiveness (VE) against school absenteeism in children 5-17 years old hospitalized from September 1, 2021 through May 31, 2023. Full vaccination was defined as two vaccine doses.

RESULTS

We studied 231 children admitted to hospital with COVID-19, including 206 (89.2 %) unvaccinated/partially vaccinated and 25 (10.8 %) fully vaccinated. Unvaccinated/partially vaccinated children were absent from school for longer periods compared to fully vaccinated children (median absence: 14 versus 10 days; p-value = 0.05). Multivariable regression showed that full COVID-19 vaccination was associated with fewer days of absence compared to no/partial vaccination on average (adjusted relative risk: 0.77; 95 % CI: 0.61 to 0.98). COVID-19 VE was 50.7 % (95 % CI: -11.3 % to 78.2 %) for school absenteeism above the median duration of absenteeism.

CONCLUSIONS

Full COVID-19 vaccination conferred protection against school absenteeism in hospitalized school-aged children with COVID-19.

Nasal vaccination of triple-RBD scaffold protein with flagellin elicits long-term protection against SARS-CoV-2 variants including JN.1

Developing a mucosal vaccine against SARS-CoV-2 is critical for combatting the epidemic. Here, we investigated long-term immune responses and protection against SARS-CoV-2 for the intranasal vaccination of a triple receptor-binding domain (RBD) scaffold protein (3R-NC) adjuvanted with a flagellin protein (KFD) (3R-NC + KFDi.n). In mice, the vaccination elicited RBD-specific broad-neutralizing antibody responses in both serum and mucosal sites sustained at high level over a year. This long-lasting humoral immunity was correlated with the presence of long-lived RBD-specific IgG- and IgA-producing plasma cells, alongside the Th17 and Tfh17-biased T-cell responses driven by the KFD adjuvant. Based upon these preclinical findings, an open labeled clinical trial was conducted in individuals who had been primed with the inactivated SARS-CoV-2 (IAV) vaccine. With a favorable safety profile, the 3R-NC + KFDi.n boost elicited enduring broad-neutralizing IgG in plasma and IgA in salivary secretions. To meet the challenge of frequently emerged variants, we further designed an updated triple-RBD scaffold protein with mutated RBD combinations, which can induce adaptable antibody responses to neutralize the newly emerging variants, including JN.1. Our findings highlight the potential of the KFD-adjuvanted triple-RBD scaffold protein is a promising prototype for the development of a mucosal vaccine against SARS-CoV-2 infection.

Predicting clinical outcomes of SARS-CoV-2 infection during the Omicron wave using machine learning

The Omicron SARS-CoV-2 variant continues to strain healthcare systems. Developing tools that facilitate the identification of patients at highest risk of adverse outcomes is a priority. The study objectives are to develop population-scale predictive models that: 1) identify predictors of adverse outcomes with Omicron surge SARS-CoV-2 infections, and 2) predict the impact of prioritized vaccination of high-risk groups for said outcome. We prepared a retrospective longitudinal observational study of a national cohort of 172,814 patients in the U.S. Veteran Health Administration who tested positive for SARS-CoV-2 from January 15 to August 15, 2022. We utilized sociodemographic characteristics, comorbidities, and vaccination status, at time of testing positive for SARS-CoV-2 to predict hospitalization, escalation of care (high-flow oxygen, mechanical ventilation, vasopressor use, dialysis, or extracorporeal membrane oxygenation), and death within 30 days. Machine learning models demonstrated that advanced age, high comorbidity burden, lower body mass index, unvaccinated status, and oral anticoagulant use were the important predictors of hospitalization and escalation of care. Similar factors predicted death. However, anticoagulant use did not predict mortality risk. The all-cause death model showed the highest discrimination (Area Under the Curve (AUC) = 0.903, 95% Confidence Interval (CI): 0.895, 0.911) followed by hospitalization (AUC = 0.822, CI: 0.818, 0.826), then escalation of care (AUC = 0.793, CI: 0.784, 0.805). Assuming a vaccine efficacy range of 70.8 to 78.7%, our simulations projected that targeted prevention in the highest risk group may have reduced 30-day hospitalization and death in more than 2 of 5 unvaccinated patients.

Ongoing Measles in the Developed and Developing World

Measles is a vaccine-preventable illness. Nevertheless, in recent years, measles is still endemic and epidemic in both the developed world and the developing world. The public perception of measles in the past was that it was not a big deal. However, measles is associated with a number of complications which can be places in three categories which are: acute(diarrhea, otitis media, pneumonia, encephalitis, seizures, and death) and delayed-subacute sclerosing panencephalitis (SSPE) and post-measles immune amnesia. Contrary to the beliefs of the anti-vaccine lobby, measles is bad. In acute measles, the death rate is 1-3 per 1000 and the risk of encephalitis is 1 per 1000. Relatively recent investigations indicate that SSPE is considerably more common than previously believed. The worldwide contribution of post-measles immune amnesia to morbidity and mortality is likely to be huge. In exposure situations, two doses of measles vaccine will prevent 99% of cases. Presently in the United States, the first dose is given at 12 through 15 months of age. The second dose is most often administered at 4 through 6 years of age. In my opinion, the second dose of measles vaccine should be given 4-6 weeks after the first dose rather than at 4-6 years of age. Children who don't have antibody to measles should not travel to risk areas.

Altered transcriptomic immune responses of maintenance hemodialysis patients to the COVID-19 mRNA vaccine

Background

End-stage renal disease (ESRD) patients experience immune compromise characterized by complex alterations of both innate and adaptive immunity, and results in higher susceptibility to infection and lower response to vaccination. This immune compromise, coupled with greater risk of exposure to infectious disease at hemodialysis (HD) centers, underscores the need for examination of the immune response to the COVID-19 mRNA-based vaccines.

Methods

The immune response to the COVID-19 BNT162b2 mRNA vaccine was assessed in 20 HD patients and cohort-matched controls. RNA sequencing of peripheral blood mononuclear cells was performed longitudinally before and after each vaccination dose for a total of six time points per subject. Anti-spike antibody levels were quantified prior to the first vaccination dose (V1D0) and 7 d after the second dose (V2D7) using anti-spike IgG titers and antibody neutralization assays. Anti-spike IgG titers were additionally quantified 6 mo after initial vaccination. Clinical history and lab values in HD patients were obtained to identify predictors of vaccination response.

Results

Transcriptomic analyses demonstrated differing time courses of immune responses, with prolonged myeloid cell activity in HD at 1 wk after the first vaccination dose. HD also demonstrated decreased metabolic activity and decreased antigen presentation compared to controls after the second vaccination dose. Anti-spike IgG titers and neutralizing function were substantially elevated in both controls and HD at V2D7, with a small but significant reduction in titers in HD groups (p<0.05). Anti-spike IgG remained elevated above baseline at 6 mo in both subject groups. Anti-spike IgG titers at V2D7 were highly predictive of 6-month titer levels. Transcriptomic biomarkers after the second vaccination dose and clinical biomarkers including ferritin levels were found to be predictive of antibody development.

Conclusions

Overall, we demonstrate differing time courses of immune responses to the BTN162b2 mRNA COVID-19 vaccination in maintenance HD subjects comparable to healthy controls and identify transcriptomic and clinical predictors of anti-spike IgG titers in HD. Analyzing vaccination as an in vivo perturbation, our results warrant further characterization of the immune dysregulation of ESRD.

Funding

F30HD102093, F30HL151182, T32HL144909, R01HL138628. This research has been funded by the University of Illinois at Chicago Center for Clinical and Translational Science (CCTS) award UL1TR002003.

Multiplex genetic manipulations in Clostridium butyricum and Clostridium sporogenes to secrete recombinant antigen proteins for oral-spore vaccination

BACKGROUND

Clostridium spp. has demonstrated therapeutic potential in cancer treatment through intravenous or intratumoral administration. This approach has expanded to include non-pathogenic clostridia for the treatment of various diseases, underscoring the innovative concept of oral-spore vaccination using clostridia. Recent advancements in the field of synthetic biology have significantly enhanced the development of Clostridium-based bio-therapeutics. These advancements are particularly notable in the areas of efficient protein overexpression and secretion, which are crucial for the feasibility of oral vaccination strategies. Here, we present two examples of genetically engineered Clostridium candidates: one as an oral cancer vaccine and the other as an antiviral oral vaccine against SARS-CoV-2.

RESULTS

Using five validated promoters and a signal peptide derived from Clostridium sporogenes, a series of full-length NY-ESO-1/CTAG1, a promising cancer vaccine candidate, expression vectors were constructed and transformed into C. sporogenes and Clostridium butyricum. Western blotting analysis confirmed efficient expression and secretion of NY-ESO-1 in clostridia, with specific promoters leading to enhanced detection signals. Additionally, the fusion of a reported bacterial adjuvant to NY-ESO-1 for improved immune recognition led to the cloning difficulties in E. coli. The use of an AUU start codon successfully mitigated potential toxicity issues in E. coli, enabling the secretion of recombinant proteins in C. sporogenes and C. butyricum. We further demonstrate the successful replacement of PyrE loci with high-expression cassettes carrying NY-ESO-1 and adjuvant-fused NY-ESO-1, achieving plasmid-free clostridia capable of secreting the antigens. Lastly, the study successfully extends its multiplex genetic manipulations to engineer clostridia for the secretion of SARS-CoV-2-related Spike_S1 antigens.

CONCLUSIONS

This study successfully demonstrated that C. butyricum and C. sporogenes can produce the two recombinant antigen proteins (NY-ESO-1 and SARS-CoV-2-related Spike_S1 antigens) through genetic manipulations, utilizing the AUU start codon. This approach overcomes challenges in cloning difficult proteins in E. coli. These findings underscore the feasibility of harnessing commensal clostridia for antigen protein secretion, emphasizing the applicability of non-canonical translation initiation across diverse species with broad implications for medical or industrial biotechnology.

Long-term monitoring of SARS-CoV-2 seroprevalence and variants in Ethiopia provides prediction for immunity and cross-immunity

Under-reporting of COVID-19 and the limited information about circulating SARS-CoV-2 variants remain major challenges for many African countries. We analyzed SARS-CoV-2 infection dynamics in Addis Ababa and Jimma, Ethiopia, focusing on reinfection, immunity, and vaccination effects. We conducted an antibody serology study spanning August 2020 to July 2022 with five rounds of data collection across a population of 4723, sequenced PCR-test positive samples, used available test positivity rates, and constructed two mathematical models integrating this data. A multivariant model explores variant dynamics identifying wildtype, alpha, delta, and omicron BA.4/5 as key variants in the study population, and cross-immunity between variants, revealing risk reductions between 24% and 69%. An antibody-level model predicts slow decay leading to sustained high antibody levels. Retrospectively, increased early vaccination might have substantially reduced infections during the delta and omicron waves in the considered group of individuals, though further vaccination now seems less impactful.

Gut microbial features may influence antiviral IgG levels after vaccination against viral respiratory infectious diseases: the evidence from two-sample bidirectional mendelian randomization

BACKGROUND

Vaccination is effective in preventing viral respiratory infectious diseases through protective antibodies and the gut microbiome has been proven to regulate human immunity. This study explores the causal correlations between gut microbial features and serum-specific antiviral immunoglobulin G (IgG) levels.

METHODS

We conduct a two-sample bidirectional Mendelian randomization (MR) analysis using genome-wide association study (GWAS) summary data to explore the causal relationships between 412 gut microbial features and four antiviral IgG (for influenza A, measles, rubella, and mumps) levels. To make the results more reliable, we used four robust methods and performed comprehensive sensitivity analyses.

RESULTS

The MR analyses revealed 26, 13, 20, and 18 causal associations of the gut microbial features influencing four IgG levels separately. ​Interestingly, ten microbial features, like genus Collinsella, species Bifidobacterium longum, and the biosynthesis of L-alanine have shown the capacity to regulate multiple IgG levels with consistent direction (rise or fall). The ​reverse MR analysis suggested several potential causal associations of IgG levels affecting microbial features.

CONCLUSIONS

The human immune response against viral respiratory infectious diseases could be modulated by changing the abundance of gut microbes, which provided new approaches for the intervention of viral respiratory infections.

Inferring COVID-19 testing and vaccination behavior from New Jersey testing data

Characterizing the relationship between disease testing behaviors and infectious disease dynamics is of great importance for public health. Tests for both current and past infection can influence disease-related behaviors at the individual level, while population-level knowledge of an epidemic's course may feed back to affect one's likelihood of taking a test. The COVID-19 pandemic has generated testing data on an unprecedented scale for tests detecting both current infection (PCR, antigen) and past infection (serology); this opens the way to characterizing the complex relationship between testing behavior and infection dynamics. Leveraging a rich database of individualized COVID-19 testing histories in New Jersey, we analyze the behavioral relationships between PCR and serology tests, infection, and vaccination. We quantify interactions between individuals' test-taking tendencies and their past testing and infection histories, finding that PCR tests were disproportionately taken by people currently infected, and serology tests were disproportionately taken by people with past infection or vaccination. The effects of previous positive test results on testing behavior are less consistent, as individuals with past PCR positives were more likely to take subsequent PCR and serology tests at some periods of the epidemic time course and less likely at others. Lastly, we fit a model to the titer values collected from serology tests to infer vaccination trends, finding a marked decrease in vaccination rates among individuals who had previously received a positive PCR test. These results exemplify the utility of individualized testing histories in uncovering hidden behavioral variables affecting testing and vaccination.

Quantitative analysis of pertussis, tetanus, and diphtheria antibodies in sera and breast milk from Tdap vaccinated women using a qualified multiplex assay

Pertussis (whooping cough) is a reemergent, highly contagious respiratory infection of public health concern. Infants prior to initiation of their primary vaccination series are the most vulnerable to severe infection, and even death. Vaccination during pregnancy is an efficacious means of reducing infection in infants. This approach relies on boosting maternal immunity and passive transfer of antibodies to the infant via placenta and breast milk. Similarly, maternal vaccination post-partum can enhance maternal-infant immunity. To support the analysis of pertussis immunity in the context of maternal-infant immunization, we developed a high throughput multiplex assay for simultaneous quantification of serum IgG antibodies against pertussis vaccine antigens: pertussis toxin (PT), filamentous hemagglutinin (FHA), pertactin (PRN), and fimbriae (FIM2/3), and against tetanus (TT) and diphtheria toxoids (DT), using the Meso Scale Discovery (MSD) platform. The assay was qualified, and specificity, sensitivity, accuracy, precision, linearity, and robustness were demonstrated. The assay was subsequently adapted for quantification of IgG and IgA in breast milk. Applied to a serological survey of pregnant women living in the United States and sub-Saharan Africa, this method revealed differences in magnitude and breadth of antibody profile, consistent with history of vaccination. A longitudinal analysis of Tdap responses in women vaccinated post-partum demonstrated a rapid increase in serum IgG that remained elevated for up to 24 months. Likewise, high levels of vaccine-specific IgA and IgG antibodies were present in breast milk, although they exhibited faster decay. This multiplex MSD assay is a reliable and practical tool for quantification of pertussis, tetanus, and diphtheria antibodies in serum and breast milk in serosurveys or vaccine studies.

IMPORTANCE

Pertussis (whooping cough) has reemerged in recent years. Vaccination during pregnancy is an effective approach to prevent illness during the first months of life. We developed a multiplex assay for quantification of pertussis, tetanus, and diphtheria serum antibodies using the Meso Scale Discovery (MSD) platform; the method was qualified, and specificity, precision, accuracy, linearity, and limits of quantification were defined. It was also adapted for quantification of antibodies in breast milk. We successfully determined serostatus in women from different regions and with different vaccination histories, as well as responses to Tdap in blood and breast milk post-partum. This is the first description of a multiplex assay for the quantification of pertussis, tetanus, and diphtheria antibodies in breast milk.

Interim Estimates of 2023-2024 Seasonal Influenza Vaccine Effectiveness Among Adults in Korea

In the 2023-2024 season, the influenza epidemic in South Korea peaked earlier than in recent years. In this study, we aimed to estimate the interim vaccine effectiveness (VE) of the influenza vaccination to prevent influenza during the early season. From November 1, 2023, to December 31, 2023, we enrolled 2,632 subjects with influenza-like illness from eight hospitals participating in hospital-based influenza morbidity and mortality surveillance. A retrospective test-negative case-control study was conducted to estimate the VE. The results showed an adjusted VE of 22.5% (95% confidence interval [CI], 6.6 to 35.8) for the total population. The adjusted VE was 22.3% (95% CI, 6.1 to 35.7) for influenza A and 9.4% (95% CI, -51.3 to 45.7) for influenza A/H1N1. Full results of the analysis will be reported.

Multiple Sclerosis Onset before and after COVID-19 Vaccination: Can HLA Haplotype Be Determinant?

A few cases of multiple sclerosis (MS) onset after COVID-19 vaccination have been reported, although the evidence is insufficient to establish causality. The aim of this study is to compare cases of newly diagnosed relapsing-remitting MS before and after the outbreak of the COVID-19 pandemic and the impact of COVID-19 vaccination. Potential environmental and genetic predisposing factors were also investigated, as well as clinical patterns. This is a single-centre retrospective cohort study including all patients who presented with relapsing-remitting MS onset between January 2018 and July 2022. Data on COVID-19 vaccination administration, dose, and type were collected. HLA-DRB1 genotyping was performed in three subgroups. A total of 266 patients received a new diagnosis of relapsing-remitting MS in our centre, 143 before the COVID-19 pandemic (until and including March 2020), and 123 during the COVID-19 era (from April 2020). The mean number of new MS onset cases per year was not different before and during the COVID-19 era and neither were baseline patients' characteristics, type of onset, clinical recovery, or radiological patterns. Fourteen (11.4%) patients who subsequently received a new diagnosis of MS had a history of COVID-19 vaccination within one month before symptoms onset. Patients' characteristics, type of onset, clinical recovery, and radiological patterns did not differ from those of patients with non-vaccine-related new diagnoses of MS. The allele frequencies of HLA-DRB1*15 were 17.6% and 22.2% in patients with non-vaccine-related disease onset before and during the COVID-19 era, respectively, while no case of HLA-DRB1*15 was identified among patients with a new diagnosis of MS post-COVID-19 vaccine. In contrast, HLA-DRB1*08+ or HLA-DRB1*10+ MS patients were present only in this subgroup. Although a causal link between COVID-19 vaccination and relapsing-remitting MS cannot be detected, it is interesting to note and speculate about the peculiarities and heterogeneities underlying disease mechanisms of MS, where the interactions of genetics and the environment could be crucial also for the follow-up and the evaluation of therapeutic options.

Multi-omics analysis reveals COVID-19 vaccine induced attenuation of inflammatory responses during breakthrough disease

The immune mechanisms mediating COVID-19 vaccine attenuation of COVID-19 remain undescribed. We conducted comprehensive analyses detailing immune responses to SARS-CoV-2 virus in blood post-vaccination with ChAdOx1 nCoV-19 or a placebo. Samples from randomised placebo-controlled trials (NCT04324606 and NCT04400838) were taken at baseline, onset of COVID-19-like symptoms, and 7 days later, confirming COVID-19 using nucleic amplification test (NAAT test) via real-time PCR (RT-PCR). Serum cytokines were measured with multiplexed immunoassays. The transcriptome was analysed with long, short and small RNA sequencing. We found attenuation of RNA inflammatory signatures in ChAdOx1 nCoV-19 compared with placebo vaccinees and reduced levels of serum proteins associated with COVID-19 severity. KREMEN1, a putative alternative SARS-CoV-2 receptor, was downregulated in placebo compared with ChAdOx1 nCoV-19 vaccinees. Vaccination ameliorates reductions in cell counts across leukocyte populations and platelets noted at COVID-19 onset, without inducing potentially deleterious Th2-skewed immune responses. Multi-omics integration links a global reduction in miRNA expression at COVID-19 onset to increased pro-inflammatory responses at the mRNA level. This study reveals insights into the role of COVID-19 vaccines in mitigating disease severity by abrogating pro-inflammatory responses associated with severe COVID-19, affirming vaccine-mediated benefit in breakthrough infection, and highlighting the importance of clinically relevant endpoints in vaccine evaluation.

Influence of vaccination on critical COVID-19 patients with acute respiratory failure: a retrospective cohort study

BACKGROUND

Despite vaccines' effectiveness in reducing COVID-19 infection rates and disease severity, their impact on critical patients presenting with acute respiratory failure is elusive. The aim of this study was to further investigate the influence of vaccination on mortality rates among severely ill COVID-19 patients experiencing acute respiratory failure.

METHODS

This retrospective cohort study was carried out at a tertiary medical center in Taiwan. From April to September 2022, patients who tested positive for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) through reverse transcription polymerase chain reaction (RT-PCR) and subsequently experienced acute respiratory failure were included in the study. Baseline characteristics, including vaccination history, along with information regarding critical illness and clinical outcomes, were gathered and compared between patients who received the vaccine and those who did not.

RESULTS

A total of 215 patients with COVID-19 exhibiting acute respiratory failure, as confirmed via RT‒PCR, were included in the analysis. Of this cohort, sixty-six (30.7%) patients died within 28 days. Neither administration of the vaccine nor achievement of primary series vaccination status had a significantly different effect on 28 day mortality, number of viral shedding events, acute respiratory distress syndrome (ARDS) incidence or other clinical outcomes. Patients who received the booster vaccine and completed the primary series showed a tendency of increased 28 days of ventilator-free status, though this difference was not statistically significant (p = 0.815).

CONCLUSIONS

Vaccination status did not significantly influence mortality rates, the occurrence of ARDS, or the viral shedding duration in COVID-19 patients with acute respiratory failure.

Monitoring HPV Prevalence and Risk Cofactors for Abnormal Cytology in the Post-Vaccination Period among Croatian Women

The incidence and mortality rate of cervical cancer in Croatia remains a health challenge despite screening efforts. Besides the persistent infection with HPV, the development of cancer is also associated with some cofactors. The goal of this study was to assess circulating HPV genotypes and risk factors for the development of cervical precancer after almost 16 years from the onset of HPV vaccination in Croatia. In this study, a total of 321 women attending gynecological care were evaluated. Relevant medical and demographic information, including cytology, were collected. HPV genotyping was performed by PCR. Comparing the HPV types found in circulation in the pre-vaccination (1999-2015) and post-vaccination periods (2020-2023), a statistically significant reduction in HPV 31 was noted, while the overall prevalence increased in the post-vaccination period. Besides the expected HPV positivity as a risk factor, the history of smoking was associated with LSIL or worse cytology at enrollment. For the first time, this population study revealed a statistically significant shift in the HPV genotype in the post-vaccination period, as well as the confirmation of risk factors for the development of abnormal cytology among Croatian women.

Reduced pertussis disease severity in infants following the introduction of pertussis vaccination of pregnant women in Spain, 2015-2019

BACKGROUND

Maternal pertussis vaccination during the third trimester of pregnancy was implemented in 2015 in Spain, reaching a national coverage of 84% in 2019. In this ecological study, we investigated whether there was a change in the disease severity for pertussis in infants upon introduction of prenatal pertussis vaccination.

METHODS

We performed a time-trend analysis of infant pertussis hospitalizations during 2005-2019 in Spain using national register data. Annual hospitalization rates per 100,000 population and the mean length of hospitalization were calculated for infants < 3 months of age (target group benefiting from the prenatal vaccination) and a reference group aged 3-11 months. We compared overall rates and annual percent changes of the above variables in both groups for the time period before (2005-2014) and after vaccination introduction (2015-2019), using segmented Poisson regression.

RESULTS

During the pre-vaccination period, infants aged 0-2 months had a 5-times higher rate of pertussis hospitalization and spent on average 50 % longer in hospital than the reference group. After the maternal vaccination introduction, the hospitalization rate decreased more rapidly in infants aged 0-2 months than in infants aged 3-11 months: annual reduction of 34 % (95 % CI: 31-38) versus 26 % (95 % CI: 21-31) in the hospitalization rate and 13 % (95 % CI: 11-15) versus 6 % (95 % CI: 2-9) in the mean hospital stay, respectively. In 2019, the mean hospital stay for pertussis was about 4.5 days in both groups.

CONCLUSIONS

Maternal pertussis vaccination in Spain led to a reduction in disease severity in the target group as compared to older infants, highlighting the need for increased efforts on educating healthcare professionals on the importance of maternal vaccinations.

Higher educational attainment associated with higher confidence in influenza vaccination in Norway

AIMS

To explore public confidence in influenza vaccination through the use of attitudinal indicators, and study whether educational attainment is related to attitudes towards influenza vaccination.

METHODS

Confidence in influenza vaccination was measured with three questions adapted from the Vaccine Confidence Project. These questions have been included in four study years of a Norwegian nationally representative telephone survey that cover influenza seasons 2016/17, 2019/20, 2020/21 and 2021/22. Over these four years, a total of 8 436 individuals aged 18-79 years responded to the survey and are included in the analysis. Risk differences (RDs) with 95 % confidence intervals were estimated using multivariable Poisson regression.

RESULTS

Influenza vaccine confidence increased over time, with approximately 80 % of the general population expressing trust in the vaccine in the 2021/22 season. There was a tendency towards higher confidence in the oldest age group (65-79 years). Moreover, confidence increased with increasing educational attainment. The proportion of participants who agreed that influenza vaccine is compatible with their basic values was close to 20 percentage points lower among those with only compulsory education than among those with higher education at graduate level, RD = -18.4 % (95 % CI -21.4 % to -15.5 %). Educational attainment was consistently associated with influenza vaccine confidence in all seasons, among risk groups 18-64 years, and among health care workers.

CONCLUSIONS

We observed an increase in confidence in influenza vaccination over the seasons examined in the study. However, the increase has not been equal in all groups and there is a clear educational gradient in influenza vaccine confidence. These findings indicate that despite efforts to increase influenza coverage over several years, the implemented measures have failed to reach all parts of the population.

Yellow fever neutralizing antibody seroprevalence proportion and titers in previously vaccinated adults with chronic kidney disease

Studies on yellow fever vaccine (YF) in chronic kidney disease (CKD) patients are scarce. This cross-sectional study aimed to evaluate YF neutralizing antibody seroprevalence and titers in previously vaccinated adults with CKD, on dialysis (D-CKD) or not (ND-CKD), compared to healthy persons. The micro Plaque Reduction Neutralization-Horseradish Peroxidase (μPRN-HP) test was used. Antibody titers were expressed as the reciprocal of the highest dilution that neutralized the challenge virus by 50 % (μPRN50). Seropositivity cut-off was set at ≥ 1:100. We included 153 participants: 46 ND-CKD, 50 D-CKD and 57 healthy adults. Median ages were 58.3, 55 and 52.2 years, respectively. Median time since YF vaccination was 22.3, 18.5 and 48.3 months respectively. There were no statistically significant differences in YF seroprevalence and neutralizing antibodies titers among groups: 100 % of ND-CKD; 96 % of D-CKD and 100 % of healthy participants were seropositive. Geometric mean titers (GMT) were 818.5, 683.0 and 665.5, respectively (p = 0.289).

A randomized, blind, parallel controlled phase I clinical trial to evaluate the safety and preliminary immunogenicity of 23-valent pneumococcal polysaccharide vaccine in healthy people aged 2 years and older

BACKGROUND

Despite some progress in pneumococcal immunization, the global burden of pneumococcal infection remains high, and pneumococcal disease remains a public health concern. Studies in China and abroad have found that 23-valent pneumococcal polysaccharide vaccine (PPV23) vaccination can effectively prevent invasive pneumococcal disease. This phase Ⅰ clinical study assessed the safety and immunogenicity of a PPV23 vaccine candidate.

METHODS

All subjects were randomly assigned to receive one dose intramuscular injection of experimental vaccine or control vaccine at a ratio of 1:1. The incidence of any adverse events was observed within 30 min, 0-7 days and 8-28 days post vaccination and the incidence of abnormal blood biochemical and blood routine indicators were tested on the 4th day post vaccination, the incidence of serious adverse events (SAEs) at 6 months post vaccination was recorded. Blood samples were collected prior to vaccination and on the 28th day post vaccination, and serum antibodies were detected by enzyme linked immunosorbent assay (ELISA).

RESULTS

The most common adverse reaction was pain at the injection site, followed by erythema. There was no significant difference of the incidence of systemic adverse reactions between the two vaccine groups. The adverse reactions observed in the trial were all common vaccination-related reactions, and no serious adverse reactions were observed. Compared to pre-vaccination, the (geometric mean concentrations) GMCs of IgG (immunoglobulin G) specific antibody against each serotype were all increased in the experimental group and the control group, there were statistical differences in seroconversion rates of serotypes 4 and 20 between the two vaccine groups.

CONCLUSION

This clinical study showed good safety of the PPV23 vaccine candidate produced by Ab&b Biotechnology Co., Ltd.JS had good safety after vaccination in people aged 2 years and older. At the same time, good immunogenicity was also demonstrated.

Exploring associations between the Big Five personality traits and cognitive ability with COVID-19 vaccination hesitancy and uptake among mothers and offspring in a UK prospective cohort study

BACKGROUND

Vaccines reduce the severity of symptoms, and risk of hospitalisation and death from infectious diseases. Yet, vaccination hesitancy persists. Research identifying psychological risk factors for vaccination hesitancy is limited and reports conflicting results. This study sought to address these inconsistencies and explore the role of personality and cognitive ability in COVID-19 vaccination hesitancy and uptake in a prospective cohort study.

METHODS

Data came from young adults (Generation-1; G1) and their mothers (Generation-0; G0) in the Avon Longitudinal Study of Parents and Children (ALSPAC). Multinomial logistic regressions, adjusting for several sociodemographic confounders, were used to explore whether personality and cognitive ability were associated with COVID-19 vaccination hesitancy and uptake. 4,960 G1 and 4,853 G0 mothers were included in the study population.

FINDINGS

Among G1, 38.4% exhibited vaccination hesitancy, yet 91.9% of the cohort received the vaccine. In adjusted models, higher levels of openness, agreeableness, conscientiousness, and cognitive ability were associated with an increased probability of wanting the vaccine. Similarly, higher levels of agreeableness, openness and cognitive ability were associated with an increased probability of vaccination uptake. However, the evidence of associations with vaccine uptake were generally weaker than with vaccination hesitancy. 56.7% of the offspring who did not want the vaccine either received the vaccine or intended to, whilst 43.3% still had no intention.Among G0 mothers, 25.6% were vaccination hesitant, yet 99.0% of the cohort received the vaccine. 3.1% said they did not want the vaccine; approximately 80% of these either received the vaccine or intended to. We found inconclusive evidence for an association between cognitive ability and vaccination hesitancy among G0 mothers.

INTERPRETATION

This study identified psychological factors associated with vaccination hesitancy and uptake. If these associations are causal, these findings may help design more effective vaccination hesitancy interventions.

Testing the impact of differing behavioural science informed text message content in COVID-19 vaccination invitations on vaccine uptake: A randomised clinical trial

Behavioural science constructs can be incorporated into messaging strategies to enhance the effectiveness of public health campaigns by increasing the occurrence of desired behaviours. This study investigated the impact of behavioural science-informed text message strategies on COVID-19 vaccination rates in 18-39-year-olds in an area of low uptake in London during the first vaccination offer round in the United Kingdom. This three-armed randomised trial recruited unvaccinated residents of an urban Central London suburb being offered their first vaccination between May and June 2021. Participants were randomised to receive the control (current practice) text message or one of two different behavioural science-informed COVID-19 vaccine invitation strategies. Both intervention strategies contained the phrase "your vaccine is ready and waiting for you", aiming to evoke a sense of ownership, with one strategy also including a pre-alert message. The main outcome measures were vaccination rates at 3 and 8 weeks after message delivery. A total of 88,820 residents were randomly assigned to one of the three trial arms. Each arm had a vaccine uptake rate of 27.2 %, 27.4 % and 27.3 % respectively. The mean age of participants was 28.2 years (SD ± 5.7), the mean index of multiple deprivation was 4.3 (SD ± 2.0) and 50.4 % were women. Vaccine uptake varied by demographics, however there was no significant difference between trial arms (p = 0.872). Delivery was successful for 53.6 % of text messages. Our choice of behavioural science informed messaging strategies did not improve vaccination rates above the rate seen for the current practice message. This likely reflects the wide exposure to public health campaigns during the pandemic, as such text messages nudges were unlikely to alter existing informed decision-making processes. Text message delivery was relatively low, indicating a need for accurate mobile phone number records and multi-modal approaches to reach eligible patients for vaccination. The protocol was registered at clinicaltrials.gov (NCT04895683) on 20/05/2021.

Influenza vaccination accuracy among adults: Self-report compared with electronic health record data

OBJECTIVE

To assess the validity of electronic health record (EHR)-based influenza vaccination data among adults in a multistate network.

METHODS

Following the 2018-2019 and 2019-2020 influenza seasons, surveys were conducted among a random sample of adults who did or did not appear influenza-vaccinated (per EHR data) during the influenza season. Participants were asked to report their influenza vaccination status; self-report was treated as the criterion standard. Results were combined across survey years.

RESULTS

Survey response rate was 44.7% (777 of 1740) for the 2018-2019 influenza season and 40.5% (505 of 1246) for the 2019-2020 influenza season. The sensitivity of EHR-based influenza vaccination data was 75.0% (95% confidence interval [CI] 68.1, 81.1), specificity 98.4% (95% CI 92.9, 99.9), and negative predictive value 73.9% (95% CI 68.0, 79.3).

CONCLUSIONS

In a multistate research network across two recent influenza seasons, there was moderate concordance between EHR-based vaccination data and self-report.

Effect of age at initiation of the human papillomavirus vaccine on the association between race/ethnicity and completion of the vaccine series

BACKGROUND

Up-to-date (UTD) of the human papillomavirus (HPV) vaccine series has been low despite 2016 recommendations for 2 doses among initiators <15 years of age and 3 doses for 15+ year olds. This study examined how age at initiation affected the association between race/ethnicity and UTD among adolescent HPV vaccine initiators. We also examined how administration of other adolescent vaccines affected UTD.

METHODS

A secondary analysis of The National Immunization Survey - Teen data between 2016 and 2020 was conducted. Characteristics associated with initiation of the vaccine series was examined and used to evaluate UTD among initiators. All data were weighted. Associations between characteristics and HPV vaccine initiation were examined using Rao Scott chi-square tests and univariable logistic regression. Multivariable binary logistic regression models stratified by race/ethnicity calculated the strength of association between independent variables and odds of initiation and UTD among initiators.

RESULTS

The final sample size was 99,719 with 67,855 (68.1 %) initiating HPV vaccination. Among HPV vaccine initiators, Hispanic and black adolescents had lower odds of UTD. However, 9-10-year-old initiators had increased odds (aOR: 5.71; 95 %CI: 3.78-8.63) of UTD compared to 12-year-old initiators. Increased odds of UTD among initiators younger than 12 years were found across racial/ethnic groups. Flu vaccination was associated with decreased odds of UTD among white (aOR: 0.76; 95 %CI:0.65-0.88) and black adolescents (aOR: 0.67; 95 %CI: 0.46-0.96).

CONCLUSION

Strong recommendations to ensure patients are UTD on the HPV vaccine series are essential to improving UTD among all adolescents and follow-up should occur when administering other vaccines to reduce missed opportunities.

Mucosal immunization with dual influenza/COVID-19 single-replication virus vector protects hamsters from SARS-CoV-2 challenge

The COVID-19 pandemic has highlighted the need for mucosal vaccines as breakthrough infections, short-lived immune responses and emergence of new variants have challenged the efficacy provided by the first generation of vaccines against SARS-CoV-2 viruses. M2SR SARS-CoV-2, an M2-deleted single-replication influenza virus vector modified to encode the SARS-CoV-2 receptor binding domain, was evaluated following intranasal delivery in a hamster challenge model for protection against Wuhan SARS-CoV-2. An adjuvanted inactivated SARS-CoV-2 whole virus vaccine administered intramuscularly was also evaluated. The intranasal M2SR SARS-CoV-2 was more effective than the intramuscular adjuvanted inactivated whole virus vaccine in providing protection against SARS-CoV-2 challenge. M2SR SARS-CoV-2 elicited neutralizing serum antibodies against Wuhan and Omicron SARS-CoV-2 viruses in addition to cross-reactive mucosal antibodies. Furthermore, M2SR SARS-CoV-2 generated serum HAI and mucosal antibody responses against influenza similar to an H3N2 M2SR influenza vaccine. The intranasal dual influenza/COVID M2SR SARS-CoV-2 vaccine has the potential to provide protection against both influenza and COVID.

Racial/ethnic differences in the associations between trust in the U.S. healthcare system and willingness to test for and vaccinate against COVID-19

BACKGROUND

Trust in the healthcare system may impact adherence to recommended healthcare practices, including willingness to test for and vaccinate against COVID-19. This study examined racial/ethnic differences in the associations between trust in the U.S. healthcare system and willingness to test for and vaccinate against COVID-19 during the first year of the pandemic.

METHODS

This cross-sectional study used data from the REACH-US study, a nationally representative online survey conducted among a diverse sample of U.S. adults from January 26, 2021-March 3, 2021 (N = 5,121). Multivariable logistic regression estimated the associations between trust in the U.S. healthcare system (measured as "Always", "Most of the time", "Sometimes/Almost Never", and "Never") and willingness to test for COVID-19, and willingness to receive the COVID-19 vaccine. Racial/ethnic differences in these associations were examined using interaction terms and multigroup analyses.

RESULTS

Always trusting the U.S. healthcare system was highest among Hispanic/Latino Spanish Language Preference (24.9%) and Asian (16.7%) adults and lowest among Multiracial (8.7%) and Black/African American (10.7%) adults. Always trusting the U.S. healthcare system, compared to never, was associated with greater willingness to test for COVID-19 (AOR: 3.20, 95% CI: 2.38-4.30) and greater willingness to receive the COVID-19 vaccine (AOR: 2.68, 95% CI: 1.97-3.65).

CONCLUSIONS

Trust in the U.S. healthcare system was associated with greater willingness to test for COVID-19 and receive the COVID-19 vaccine, however, trust in the U.S. healthcare system was lower among most marginalized racial/ethnic groups. Efforts to establish a more equitable healthcare system that increases trust may encourage COVID-19 preventive behaviors.

High COVID-19 vaccine uptake following initial hesitancy among people in Australia who inject drugs

BACKGROUND

Previous studies have reported high COVID-19 vaccine hesitancy among people who inject drugs. We aimed to examine COVID-19 vaccine coverage, motivations and barriers to vaccination, and factors associated with uptake among this population in Australia, 1.5 years after vaccine rollout commenced.

METHODS

In June-July 2022, 868 people (66.0 % male, mean age 45.6 years) who regularly inject drugs and reside in an Australian capital city reported the number of COVID-19 vaccine doses they had received and their primary motivation (if vaccinated) or barrier (if unvaccinated) to receive the vaccine. We compared vaccine uptake to Australian population estimates and used logistic regression to identify factors associated with ≥ 2 dose and ≥ 3 dose uptake.

RESULTS

Overall, 84.1 % (n = 730) had received at least one COVID-19 vaccine dose, 79.6 % (n = 691) had received ≥ 2 doses, and 46.1 % (n = 400) had received ≥ 3 doses. Participants were less likely to be vaccinated than the Australian general population (prevalence ratio: 0.82, 95 % confidence interval [CI]: 0.76-0.88). Key motivations to receive the vaccine were to protect oneself or others from COVID-19, while barriers pertained to vaccine or government distrust. Opioid agonist treatment (adjusted odds ratio [aOR]: 2.49, 95 % CI: 1.44-4.42), current seasonal influenza vaccine uptake (aOR: 6.76, 95 % CI: 3.18-16.75), and stable housing (aOR: 1.58, 95 % CI: 1.02-2.80) were associated with receipt of at least two vaccine doses. Participants aged ≥ 40 years (versus < 40 years; aOR: 1.66, 95 % CI: 1.10-2.53) or who reported a chronic health condition (aOR: 1.71, 95 % CI: 1.18-2.47) had higher odds of receiving at least three vaccine doses.

CONCLUSION

We observed higher COVID-19 vaccine uptake than expected given previous studies of vaccine acceptability among people who inject drugs. However, it was lower than the general population. People who inject drugs and reside in unstable housing are a subpopulation that require support to increase vaccine uptake.

Facilitators and barriers to vaccination uptake in pregnancy: A qualitative systematic review

INTRODUCTION

Vaccination during pregnancy protects both the mother and the foetus from vaccine-preventable diseases. However, uptake of the recommended vaccines (influenza, pertussis, COVID-19) by pregnant women remains low in Europe and the USA. Understanding the reasons for this is crucial to inform strategies to increase vaccination rates in pregnant women. This qualitative systematic review aimed to identify the barriers and facilitators to vaccination against influenza, pertussis/whooping cough and COVID-19 during pregnancy and identify possible strategies to increase vaccination rates.

METHODS

We conducted a comprehensive search of electronic databases, including Medline, PsycINFO, CINAHL, Web of Science, WHO database, Embase and grey literature to identify qualitative studies that explored barriers and facilitators to vaccine uptake among pregnant women (PROSPERO CRD42023399488). The search was limited to studies published between 2012 and 2022 conducted in high-income countries with established vaccination programmes during pregnancy. Studies were thematically analysed and underwent quality assessment using the Joanna Briggs Institute validated critical appraisal tool for qualitative research.

RESULTS

Out of 2681 articles screened, 28 studies (n = 1573 participants) were eligible for inclusion. Five overarching themes emerged relating to personal, provider and systemic factors. Barriers to vaccine uptake included concerns about vaccine safety and efficacy, lack of knowledge about vaccines' benefits and necessity, fear of adverse effects on the foetus or mother and low perception of disease severity. Facilitators included recommendations from trusted healthcare providers, easy access to vaccination, clear communication on the benefits and safety of vaccination, and positive social influences from family and friends. Strategies for increasing vaccination uptake included strong and proactive vaccine recommendations by trusted healthcare professionals, provision of vaccines during routine antenatal care, and clear and consistent communication about vaccines addressing pregnant women's concerns.

CONCLUSION

This review highlights the need for interventions that address the identified barriers to vaccine uptake among pregnant women. Recommendation from a healthcare provider can play a significant role in promoting vaccine uptake, as can clear risk/benefit communication and convenient access to vaccination. Addressing concerns about vaccine safety and providing accurate information about vaccines is also important.

SARS-CoV-2 booster vaccine dose significantly extends humoral immune response half-life beyond the primary series

SARS-CoV-2 lipid nanoparticle mRNA vaccines continue to be administered as the predominant prophylactic measure to reduce COVID-19 disease pathogenesis. Quantifying the kinetics of the secondary immune response from subsequent doses beyond the primary series and understanding how dose-dependent immune waning kinetics vary as a function of age, sex, and various comorbidities remains an important question. We study anti-spike IgG waning kinetics in 152 individuals who received an mRNA-based primary series (first two doses) and a subset of 137 individuals who then received an mRNA-based booster dose. We find the booster dose elicits a 71-84% increase in the median Anti-S half life over that of the primary series. We find the Anti-S half life for both primary series and booster doses decreases with age. However, we stress that although chronological age continues to be a good proxy for vaccine-induced humoral waning, immunosenescence is likely not the mechanism, rather, more likely the mechanism is related to the presence of noncommunicable diseases, which also accumulate with age, that affect immune regulation. We are able to independently reproduce recent observations that those with pre-existing asthma exhibit a stronger primary series humoral response to vaccination than compared to those that do not, and further, we find this result is sustained for the booster dose. Finally, via a single-variate Kruskal-Wallis test we find no difference between male and female humoral decay kinetics, however, a multivariate approach utilizing  Least Absolute Shrinkage and Selection Operator (LASSO) regression for feature selection reveals a statistically significant (p < 1 × 10 - 3 ), albeit small, bias in favour of longer-lasting humoral immunity amongst males.

Regional variations in vaccination against COVID-19 in Germany

Vaccination willingness against COVID-19 is generally perceived as low. Moreover, there is large heterogeneity across and within countries. As a whole, Germany has average vaccination rates compared to other industrialized countries. However, vaccination rates in the 16 different German federal states differ by more than 20 percentage points. We describe variation in vaccination rates on the level of the 400 German counties using data on all vaccinations carried out until December 2022. Around 52-72% of that variation can be explained by regional differences in demographic characteristics, housing, education and political party preferences. We find indications that the remaining part may be due to differences in soft factors such as risk aversion, trust in the German government, trust in science, and beliefs in conspiracy theories regarding the origins of the Corona virus. We conclude that improving the trust in science and the fight against conspiracy theories may possibly be effective tools to improve vaccination rates and effectively fight pandemics.

COVID-19 Vaccination Coverage, and Rates of SARS-CoV-2 Infection and COVID-19-Associated Hospitalization Among Residents in Nursing Homes - National Healthcare Safety Network, United States, October 2023-February 2024

Nursing home residents are at increased risk for developing severe COVID-19. Nursing homes report weekly facility-level data on SARS-CoV-2 infections, COVID-19-associated hospitalizations, and COVID-19 vaccination coverage among residents to CDC's National Healthcare Safety Network. This analysis describes rates of incident SARS-CoV-2 infection, rates of incident COVID-19-associated hospitalization, and COVID-19 vaccination coverage during October 16, 2023-February 11, 2024. Weekly rates of SARS-CoV-2 infection ranged from 61.4 to 133.8 per 10,000 nursing home residents. The weekly percentage of facilities reporting one or more incident SARS-CoV-2 infections ranged from 14.9% to 26.1%. Weekly rates of COVID-19-associated hospitalization ranged from 3.8 to 7.1 per 10,000 residents, and the weekly percentage of facilities reporting one or more COVID-19-associated hospitalizations ranged from 2.6% to 4.7%. By February 11, 2024, 40.5% of nursing home residents had received a dose of the updated 2023-2024 COVID-19 vaccine that was first recommended in September 2023. Although the peak rate of SARS-CoV-2 infection among nursing home residents was lower during the 2023-24 respiratory virus season than during the three previous respiratory virus seasons, nursing home residents continued to be disproportionately affected by SARS-CoV-2 infection and related severe outcomes. Vaccination coverage remains suboptimal in this population. Ongoing surveillance for SARS-CoV-2 infections and COVID-19-associated hospitalizations in this population is necessary to develop and evaluate evidence-based interventions for protecting nursing home residents.

Pneumococcal vaccination and primary care presentations for acute respiratory tract infection and antibiotic prescribing in older adults

BACKGROUND

While the 23-valent pneumococcal polysaccharide vaccine (PPV23) has demonstrated its role in preventing severe pneumococcal disease, its impact on more non-specific conditions like acute respiratory tract infection (ARI) and lower respiratory tract infections (LRTI) remains unclear. We aimed to investigate the role of PPV23 in prevention of presentations for ARI and LRTI and related antibiotic prescriptions among older adults in primary care.

METHODS

Using a nationwide general practice dataset, we followed a cohort of regularly attending patients aged ≥65 years from 1 January 2014 until 31 December 2018 for presentations for ARI, LRTI, and related antibiotic prescriptions. Associations between PPV23 receipt and each outcome were assessed using a multiple failures survival model to estimate hazard ratios (HR) adjusted for age, sex, socioeconomic status, and various health measures.

RESULTS

A cohort of 75,264 patients aged ≥65 years (mean 75.4, 56% female) in 2014 was followed. The incidence of presentations for ARI, ARI-related antibiotic prescription, LRTI, and LRTI-related antibiotic prescription was 157.6, 76.0, 49.6, and 24.3 per 1000 person-years, respectively. Recent PPV23 vaccine receipt was associated with a small reduction in ARI presentations (adjusted HR vaccinated vs. unvaccinated 0.96; 95%CI 0.94-0.98; p = 0.002); however, there was no reduction in ARI-related antibiotic prescription, LRTI presentation, nor LRTI-related antibiotic prescription (adjusted HR were 0.99[95%CI 0.96-1.03], 1.04[95%CI 0.99-1.09], 1.07[95%CI 1.00-1.14]).

CONCLUSION

PPV23 vaccination in older adults may result in a small reduction in the incidence of total ARI presentations in primary care. However, the effect is small and residual confounding cannot be excluded.

Immunogenicity of COVID-19 booster vaccination in IEI patients and their one year clinical follow-up after start of the COVID-19 vaccination program

Purpose

Previous studies have demonstrated that the majority of patients with an inborn error of immunity (IEI) develop a spike (S)-specific IgG antibody and T-cell response after two doses of the mRNA-1273 COVID-19 vaccine, but little is known about the response to a booster vaccination. We studied the immune responses 8 weeks after booster vaccination with mRNA-based COVID-19 vaccines in 171 IEI patients. Moreover, we evaluated the clinical outcomes in these patients one year after the start of the Dutch COVID-19 vaccination campaign.

Methods

This study was embedded in a large prospective multicenter study investigating the immunogenicity of COVID-19 mRNA-based vaccines in IEI (VACOPID study). Blood samples were taken from 244 participants 8 weeks after booster vaccination. These participants included 171 IEI patients (X-linked agammaglobulinemia (XLA;N=11), combined immunodeficiency (CID;N=4), common variable immunodeficiency (CVID;N=45), isolated or undefined antibody deficiencies (N=108) and phagocyte defects (N=3)) and 73 controls. SARS-CoV-2-specific IgG titers, neutralizing antibodies, and T-cell responses were evaluated. One year after the start of the COVID-19 vaccination program, 334 study participants (239 IEI patients and 95 controls) completed a questionnaire to supplement their clinical data focusing on SARS-CoV-2 infections.

Results

After booster vaccination, S-specific IgG titers increased in all COVID-19 naive IEI cohorts and controls, when compared to titers at 6 months after the priming regimen. The fold-increases did not differ between controls and IEI cohorts. SARS-CoV-2-specific T-cell responses also increased equally in all cohorts after booster vaccination compared to 6 months after the priming regimen. Most SARS-CoV-2 infections during the study period occurred in the period when the Omicron variant had become dominant. The clinical course of these infections was mild, although IEI patients experienced more frequent fever and dyspnea compared to controls and their symptoms persisted longer.

Conclusion

Our study demonstrates that mRNA-based booster vaccination induces robust recall of memory B-cell and T-cell responses in most IEI patients. One-year clinical follow-up demonstrated that SARS-CoV-2 infections in IEI patients were mild. Given our results, we support booster campaigns with newer variant-specific COVID-19 booster vaccines to IEI patients with milder phenotypes.

Adaptive immune responses to two-dose COVID-19 vaccine series in healthy Canadian adults ≥ 50 years: a prospective, observational cohort study

To evaluate immune responses to COVID-19 vaccines in adults aged 50 years and older, spike protein (S)-specific antibody concentration, avidity, and function (via angiotensin-converting enzyme 2 (ACE2) inhibition surrogate neutralization and antibody dependent cellular phagocytosis (ADCP)), as well as S-specific T cells were quantified via activation induced marker (AIM) assay in response to two-dose series. Eighty-four adults were vaccinated with either: mRNA/mRNA (mRNA-1273 and/or BNT162b2); ChAdOx1-S/mRNA; or ChAdOx1-S/ChAdOx1-S. Anti-S IgG concentrations, ADCP scores and ACE2 inhibiting antibody concentrations were highest at one-month post-second dose and declined by four-months post-second dose for all groups. mRNA/mRNA and ChAdOx1-S/mRNA schedules had significantly higher antibody responses than ChAdOx1-S/ChAdOx1-S. CD8+ T-cell responses one-month post-second dose were associated with increased ACE2 surrogate neutralization. Antibody avidity (total relative avidity index) did not change between one-month and four-months post-second dose and did not significantly differ between groups by four-months post-second dose. In determining COVID-19 correlates of protection, a measure that considers both antibody concentration and avidity should be considered.

Antibodies Induced by Smallpox Vaccination after at Least 45 Years Cross-React with and In Vitro Neutralize Mpox Virus: A Role for Polyclonal B Cell Activation?

AIMS

To evaluate whether antibodies specific for the vaccinia virus (VV) are still detectable after at least 45 years from immunization. To confirm that VV-specific antibodies are endowed with the capacity to neutralize Mpox virus (MPXV) in vitro. To test a possible role of polyclonal non-specific activation in the maintenance of immunologic memory.

METHODS

Sera were collected from the following groups: smallpox-vaccinated individuals with or without latent tuberculosis infection (LTBI), unvaccinated donors, and convalescent individuals after MPXV infection. Supernatant of VV- or MPXV-infected Vero cells were inactivated and used as antigens in ELISA or in Western blot (WB) analyses. An MPXV plaque reduction neutralization test (PRNT) was optimized and performed on study samples. VV- and PPD-specific memory T cells were measured by flow cytometry.

RESULTS

None of the smallpox unvaccinated donors tested positive in ELISA or WB analysis and their sera were unable to neutralize MPXV in vitro. Sera from all the individuals convalescing from an MPXV infection tested positive for anti-VV or MPXV IgG with high titers and showed MPXV in vitro neutralization capacity. Sera from most of the vaccinated individuals showed IgG anti-VV and anti-MPXV at high titers. WB analyses showed that positive sera from vaccinated or convalescent individuals recognized both VV and MPXV antigens. Higher VV-specific IgG titer and specific T cells were observed in LTBI individuals.

CONCLUSIONS

ELISA and WB performed using supernatant of VV- or MPXV-infected cells are suitable to identify individuals vaccinated against smallpox at more than 45 years from immunization and individuals convalescing from a recent MPXV infection. ELISA and WB results show a good correlation with PRNT. Data confirm that a smallpox vaccination induces a long-lasting memory in terms of specific IgG and that antibodies raised against VV may neutralize MPXV in vitro. Finally, higher titers of VV-specific antibodies and higher frequency of VV-specific memory T cells in LTBI individuals suggest a role of polyclonal non-specific activation in the maintenance of immunologic memory.

COVID-19 vaccine acceptance in the general population and under-resourced communities from high-income countries: realist review

OBJECTIVE

To compare vaccination willingness before rollout and 1 year post-rollout uptake among the general population and under-resourced communities in high-income countries.

DESIGN

A realist review.

DATA SOURCES

Embase, PubMed, Dimensions ai and Google Scholar.

SETTING

High-income countries.

DEFINITIONS

We defined vaccination willingness as the proportion of participants willing or intending to receive vaccines prior to availability. We defined vaccine uptake as the real proportion of the population with complete vaccination as reported by each country until November 2021.

RESULTS

We included data from 62 studies and 18 high-income countries. For studies conducted among general populations, the proportion of vaccination willingness was 67% (95% CI 62% to 72%). In real-world settings, the overall proportion of vaccine uptake among those countries was 73% (95% CI 69% to 76%). 17 studies reported pre-rollout willingness for under-resourced communities. The summary proportion of vaccination willingness from studies reporting results among people from under-resourced communities was 52% (95% CI 0.46% to 0.57%). Real-world evidence about vaccine uptake after rollout among under-resourced communities was limited.

CONCLUSION

Our review emphasises the importance of realist reviews for assessing vaccine acceptance. Limited real-world evidence about vaccine uptake among under-resourced communities in high-income countries is a call to context-specific actions and reporting.

COVID-19 vaccine hesitancy among adults in Liberia, April-May 2021

BACKGROUND

Vaccination is one of the most cost-effective public health interventions used to prevent diseases in susceptible populations. Despite the established efficacy of vaccines, there are many reasons people are hesitant about vaccination, and these reasons could be complex. This rapid survey estimated the prevalence of COVID-19 vaccine hesitancy and potentially contributing factors in Montserrado and Nimba counties in Liberia.

METHODS

A cross-sectional study was conducted among adults living in Liberia. The relationship between vaccine non-acceptance and sociodemographic characteristics was examined using chi-square statistics. The variables with a p-value less than 0.2 at the bivariate analysis were modelled in a binary logistic regression at a 5% level of significance. The adjusted odds ratio and 95% confidence interval are reported.

RESULTS

There were 877 participants in the study. Majority were 25-34 years of age (30.4%, 272/877), females (54.05%, 474/877), and Christians (85.2%, 747/877). Most of the participants were aware of the COVID-19 vaccine (75%, 656/877), single (41.4%, 363/877), self-employed (37.51%, 329/877), and live-in rural communities (56.1%, 492/877). Vaccine hesitancy was (29.1%, 255/877; 95% CI:26.2-32.2). Vaccine hesitancy was greater among adults living in urban areas (41%) compared to persons living in rural communities (59%) (aOR; 1.5, 95% CI: 1.1-2.1) and respondents aged 45-54 years (aOR:0.5; 95% CI: 0.2-0.9; p = 0.043) were 50% less likely to be hesitant to COVID-19 vaccination compared to those more than 55 years. The most common source of information was the media (53%, 492/877) and the main reason for being hesitant was a need for more information about the vaccine and its safety (84%, 215/255).

CONCLUSIONS

The majority of study participants were aware of the COVID-19 vaccines and their most common source of information was the media (television, radio). Vaccine hesitancy was moderate. This could pose a challenge to efforts to control the spread of the COVID-19 pandemic. Therefore, the health authorities should provide more health education on the importance of vaccines and their safety to the populace.

Factors associated with malaria vaccine uptake in Nsanje district, Malawi

BACKGROUND

Malaria remains a significant global health burden affecting millions of people, children under 5 years and pregnant women being most vulnerable. In 2019, the World Health Organization (WHO) endorsed the introduction of RTS,S/AS01 malaria vaccine as Phase IV implementation evaluation in three countries: Malawi, Kenya and Ghana. Acceptability and factors influencing vaccination coverage in implementing areas is relatively unknown. In Malawi, only 60% of children were fully immunized with malaria vaccine in Nsanje district in 2021, which is below 80% WHO target. This study aimed at exploring factors influencing uptake of malaria vaccine and identify approaches to increase vaccination.

METHODS

In a cross-sectional study conducted in April-May, 2023, 410 mothers/caregivers with children aged 24-36 months were selected by stratified random sampling and interviewed using a structured questionnaire. Vaccination data was collected from health passports, for those without health passports, data was collected using recall history. Regression analyses were used to test association between independent variables and full uptake of malaria vaccine.

RESULTS

Uptake of malaria vaccine was 90.5% for dose 1, but reduced to 87.6%, 69.5% and 41.2% for dose 2, 3, and 4 respectively. Children of caregivers with secondary or upper education and those who attended antenatal clinic four times or more had increased odds of full uptake of malaria vaccine [OR: 2.43, 95%CI 1.08-6.51 and OR: 1.89, 95%CI 1.18-3.02], respectively. Children who ever suffered side-effects following immunization and those who travelled long distances to reach the vaccination centre had reduced odds of full uptake of malaria vaccine [OR: 0.35, 95%CI 0.06-0.25 and OR: 0.30, 95%CI 0.03-0.39] respectively. Only 17% (n = 65) of mothers/caregivers knew the correct schedule for vaccination and 38.5% (n = 158) knew the correct number of doses a child was to receive.

CONCLUSION

Only RTS,S dose 1 and 2 uptake met WHO coverage targets. Mothers/caregivers had low level of information regarding malaria vaccine, especially on numbers of doses to be received and dosing schedule. The primary modifiable factor influencing vaccine uptake was mother/caregiver knowledge about the vaccine. Thus, to increase the uptake Nsanje District Health Directorate should strengthen communities' education about malaria vaccine. Programmes to strengthen mother/caregiver knowledge should be included in scale-up of the vaccine in Malawi and across sub-Saharan Africa.