Effectiveness of COVID-19 mRNA Vaccines Against COVID-19-Associated Hospitalization - Five Veterans Affairs Medical Centers, United States, February 1-August 6, 2021

Watchful, skeptics, and system distrusters: Characteristics associated with different types of COVID-19 vaccine hesitancy among U.S. working-age adults

COVID-19 vaccine hesitancy is complex, with adults identifying various reasons for not getting vaccinated. Using data from the 2022 National Wellbeing Survey on 7612 U.S. adults aged 18-64, we identified how age, race/ethnicity, sex, marital status, education, income, employment status, partisanship, and metropolitan status are associated with COVID-19 vaccination status and three non-mutually exclusive types of vaccine hesitancy: 1) watchful, concerned about vaccine side effects and efficacy; 2) skeptics, distrust the vaccine, and 3) system distrusters, distrust government. A third of respondents overall (N = 2643) had not received at least one dose at the time of the survey. Among respondents who were not vaccinated, 67 % are classified as watchful, 53 % are skeptics, and 32 % are system distrusters. Results from logistic regression show that concerns about side effects and safety (watchfulness) appear to be major drivers for not getting vaccinated among females and among non-Hispanic Black and unmarried adults, whereas skepticism and distrust appear to be more important barriers among ages 25-44. All three types of hesitancy appear to be important contributors to lower vaccination uptake among low-income, low-education, and unemployed adults, and among individuals who voted for Donald Trump in the 2020 election (with skepticism and distrust being most endorsed by this group). Findings suggest that universal messaging and intervention strategies are unlikely to be effective in reducing vaccine hesitancy. Different messages, messengers, and tactics must be used with different groups.

Prior COVID-19 Diagnosis, Severe Outcomes, and Long COVID among U.S. Adults, 2022

Given the increase in COVID-19 emergency department visits and hospitalizations during the winter of 2023-2024, identifying groups that have a high prevalence of COVID-19 cases, severity, and long-term symptoms can help increase efforts toward reducing disparities and prevent severe COVID-19 outcomes. Using data from the 2022 National Health Interview Survey (n = 27,651), we assessed the prevalence of COVID-19 outcomes (prior diagnosis, moderate/severe COVID-19, and long COVID) by sociodemographic characteristics and factors associated with each COVID-19 outcome. Approximately one third of adults reported a prior COVID-19 diagnosis (30.7%), while one half (51.6%) who had COVID-19 reported moderate or severe symptoms, and one fifth (19.7%) who had COVID-19 symptoms reported long COVID. The following were associated with higher odds of moderate/severe COVID-19 and long COVID: havinga high-risk condition (aOR = 1.20, OR = 1.52); having anxiety or depression (OR = 1.46, OR = 1.49); having a disability (OR = 1.41, OR = 1.60); and having a food insecurity (OR = 1.37, OR = 1.50) compared to a lack of these conditions. Having two or more COVID-19 vaccinations was associated with lower odds of a COVID-19 diagnosis (OR = 0.75), moderate/severe COVID-19 (OR = 0.86), and long COVID (OR = 0.82). Improving vaccination coverage and reducing disparities in COVID-19 outcomes could advance health equities and protect against future resurgence of disease.

Cardiac delivery of modified mRNA using lipid nanoparticles: Cellular targets and biodistribution after intramyocardial administration

Despite research efforts being made towards preserving (or even regenerating) heart tissue after an ischemic event, there is a lack of resources in current clinical treatment modalities for patients with acute myocardial infarction that specifically address cardiac tissue impairment. Modified messenger RNA (modRNA) presents compelling properties that could allow new therapeutic strategies to tackle the underlying molecular pathways that ultimately lead to development of chronic heart failure. However, clinical application of modRNA for the heart is challenged by the lack of effective and safe delivery systems. Lipid nanoparticles (LNPs) represent a well characterized class of RNA delivery systems, which were recently approved for clinical usage in mRNA-based COVID-19 vaccines. In this study, we evaluated the potential of LNPs for cardiac delivery of modRNA. We tested how variations in C12-200 modRNA-LNP composition affect transfection levels and biodistribution after intramyocardial administration in both healthy and myocardial-infarcted mice, and determined the targeted cardiac cell types. Our data revealed that LNP-mediated modRNA delivery outperforms the current state of the art (modRNA in citrate buffer) upon intramyocardial administration in mice, with only minor differences among the formulations tested. Furthermore, we determined both in vitro and in vivo that the cardiac cells targeted by modRNA-LNPs include fibroblasts, endothelial cells and epicardial cells, suggesting that these cell types could represent targets for therapeutic interference with these LNP formulations. These outcomes may serve as a starting point for LNP development specifically for therapeutic mRNA cardiac delivery applications.

Effectiveness of BNT162b2 COVID-19 primary series vaccination in children aged 5-17 years in the United States: a cohort study

BACKGROUND

COVID-19 vaccines are authorized for use in children in the United States; real-world assessment of vaccine effectiveness in children is needed. This study's objective was to estimate the effectiveness of receiving a complete primary series of monovalent BNT162b2 (Pfizer-BioNTech) COVID-19 vaccine in US children.

METHODS

This cohort study identified children aged 5-17 years vaccinated with BNT162b2 matched with unvaccinated children. Participants and BNT162b2 vaccinations were identified in Optum and CVS Health insurance administrative claims databases linked with Immunization Information System (IIS) COVID-19 vaccination records from 16 US jurisdictions between December 11, 2020, and May 31, 2022 (end date varied by database and IIS). Vaccinated children were followed from their first BNT162b2 dose and matched to unvaccinated children on calendar date, US county of residence, and demographic and clinical factors. Censoring occurred if vaccinated children failed to receive a timely dose 2 or if unvaccinated children received any dose. Two COVID-19 outcome definitions were evaluated: COVID-19 diagnosis in any medical setting and COVID-19 diagnosis in hospitals/emergency departments (EDs). Propensity score-weighted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated with Cox proportional hazards models, and vaccine effectiveness (VE) was estimated as 1 minus HR. VE was estimated overall, within age subgroups, and within variant-specific eras. Sensitivity, negative control, and quantitative bias analyses evaluated various potential biases.

RESULTS

There were 453,655 eligible vaccinated children one-to-one matched to unvaccinated comparators (mean age 12 years; 50% female). COVID-19 hospitalizations/ED visits were rare in children, regardless of vaccination status (Optum, 41.2 per 10,000 person-years; CVS Health, 44.1 per 10,000 person-years). Overall, vaccination was associated with reduced incidence of any medically diagnosed COVID-19 (meta-analyzed VE = 38% [95% CI, 36-40%]) and hospital/ED-diagnosed COVID-19 (meta-analyzed VE = 61% [95% CI, 56-65%]). VE estimates were lowest among children 5-11 years and during the Omicron-variant era.

CONCLUSIONS

Receipt of a complete BNT162b2 vaccine primary series was associated with overall reduced medically diagnosed COVID-19 and hospital/ED-diagnosed COVID-19 in children; observed VE estimates differed by age group and variant era.

REGISTRATION

The study protocol was publicly posted on the BEST Initiative website ( https://bestinitiative.org/wp-content/uploads/2022/03/C19-VX-Effectiveness-Protocol_2022_508.pdf ).

Predicting Vaccine Effectiveness for Hospitalization and Symptomatic Disease for Novel SARS-CoV-2 Variants Using Neutralizing Antibody Titers

The emergence of new virus variants, including the Omicron variant (B.1.1.529) of SARS-CoV-2, can lead to reduced vaccine effectiveness (VE) and the need for new vaccines or vaccine doses if the extent of immune evasion is severe. Neutralizing antibody titers have been shown to be a correlate of protection for SARS-CoV-2 and other pathogens, and could be used to quickly estimate vaccine effectiveness for new variants. However, no model currently exists to provide precise VE estimates for a new variant against severe disease for SARS-CoV-2 using robust datasets from several populations. We developed predictive models for VE against COVID-19 symptomatic disease and hospitalization across a 54-fold range of mean neutralizing antibody titers. For two mRNA vaccines (mRNA-1273, BNT162b2), models fit without Omicron data predicted that infection with the BA.1 Omicron variant increased the risk of hospitalization 2.8-4.4-fold and increased the risk of symptomatic disease 1.7-4.2-fold compared to the Delta variant. Out-of-sample validation showed that model predictions were accurate; all predictions were within 10% of observed VE estimates and fell within the model prediction intervals. Predictive models using neutralizing antibody titers can provide rapid VE estimates, which can inform vaccine booster timing, vaccine design, and vaccine selection for new virus variants.

Prototype and BA.5 protein nanoparticle vaccines protect against Omicron BA.5 variant in Syrian hamsters

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with greater transmissibility or immune evasion properties has jeopardized the existing vaccine and antibody-based countermeasures. Here, we evaluated the efficacy of boosting pre-immune hamsters with protein nanoparticle vaccines (Novavax, Inc.) containing recombinant Prototype (Wuhan-1) or BA.5 S proteins against a challenge with the Omicron BA.5 variant of SARS-CoV-2. Serum antibody binding and neutralization titers were quantified before challenge, and viral loads were measured 3 days after challenge. Boosting with Prototype or BA.5 vaccine induced similar antibody binding responses against ancestral Wuhan-1 or BA.5 S proteins, and neutralizing activity of Omicron BA.1 and BA.5 variants. One and three months after vaccine boosting, hamsters were challenged with the Omicron BA.5 variant. Prototype and BA.5 vaccine-boosted hamsters had reduced viral infection in the nasal washes, nasal turbinates, and lungs compared to unvaccinated animals. Although no significant differences in virus load were detected between the Prototype and BA.5 vaccine-boosted animals, fewer breakthrough infections were detected in the BA.5-vaccinated hamsters. Thus, immunity induced by Prototype or BA.5 S protein nanoparticle vaccine boosting can protect against the Omicron BA.5 variant in the Syrian hamster model.

IMPORTANCE

As SARS-CoV-2 continues to evolve, there may be a need to update the vaccines to match the newly emerging variants. Here, we compared the protective efficacy of the updated BA.5 and the original Wuhan-1 COVID-19 vaccine against a challenge with the BA.5 Omicron variant of SARS-CoV-2 in hamsters. Both vaccines induced similar levels of neutralizing antibodies against multiple variants of SARS-CoV-2. One and three months after the final immunization, hamsters were challenged with BA.5. No differences in protection against the BA.5 variant virus were observed between the two vaccines, although fewer breakthrough infections were detected in the BA.5-vaccinated hamsters. Together, our data show that both protein nanoparticle vaccines are effective against the BA.5 variant of SARS-CoV-2 but given the increased number of breakthrough infections and continued evolution, it is important to update the COVID-19 vaccine for long-term protection.

Vaccines reduced hospital length of stay and fraction of inspired oxygen of COVID-19 patients: A retrospective cohort study

Few studies have focused on the evaluation of vaccine effectiveness (VE) in mainland China. This study was to characterize the VE including the frequent symptoms, laboratory indices, along with endotracheal intubation, hospital length of stay (LoS), and survival status. This retrospective cohort study included patients with COVID-19 admitted to our hospital. Statistical comparisons of continuous variables were carried out with an independent Student's t-test or Mann-Whitney U test. For categorical variables, the Chi-square test and Fisher exact test were used. Multivariable regression analysis was performed to adjust the confounding factors such as age, gender, body mass index (BMI), residential area, smoking status, the Charlson comorbidity index (CCI) score, followed by investigating the effects of vaccination on critical ill prevention, reduced mortality and endotracheal intubation, LoS and inspired oxygen. This study included 549 hospitalized patients with COVID-19, including 222 (40.43 %) vaccinated participants and 327 (59.57 %) unvaccinated counterparts. There was no obvious difference between the two groups in typical clinical symptoms of COVID-19, clinical laboratory results and mortality. Multivariable analysis showed that COVID-19 vaccine obviously reduced LoS by 1.2 days (lnLoS = -0.14, 95 %CI[-0.24,-0.04]; P = 0.005) and decreased fraction of inspired oxygen by 40 % (OR: 0.60; 95 %CI[0.40,0.90]; P = 0.013) after adjusting age, gender, BMI, residential area, smoking status and CCI score. In contrast, vaccination induced reduction in the critically ill, mortality, and endotracheal intubation compared with the unvaccinated counterparts, but with no statistical differences. Vaccinated patients hospitalized with COVID-19 have a reduced LoS and fraction of inspired oxygen compared to unvaccinated cases in China.

Immunogenicity and efficacy of XBB.1.5 rS vaccine against EG.5.1 variant of SARS-CoV-2 in Syrian hamsters

The continued emergence of SARS-CoV-2 variants necessitates updating COVID-19 vaccines to match circulating strains. The immunogenicity and efficacy of these vaccines must be tested in pre-clinical animal models. In Syrian hamsters, we measured the humoral and cellular immune response after immunization with the nanoparticle recombinant Spike (S) protein-based COVID-19 vaccine (Novavax, Inc.). We also compared the efficacy of the updated monovalent XBB.1.5 variant vaccine to previous COVID-19 vaccines for the induction of XBB.1.5 and EG.5.1 neutralizing antibodies and protection against a challenge with the EG.5.1 variant of SARS-CoV-2. Immunization induced high levels of spike-specific serum IgG and IgA antibodies, S-specific IgG and IgA antibody secreting cells, and antigen specific CD4 + T-cells. The XBB.1.5 and XBB.1.16 vaccines, but not the Prototype vaccine, induced high levels of neutralizing antibodies against XBB.1.5 and EG.5.1 variants of SARS-CoV-2. Upon challenge with the Omicron EG.5.1 variant, the XBB.1.5 and XBB.1.16 vaccines reduced the virus load in the lungs, nasal turbinates, trachea and nasal washes. The bivalent vaccine continued to offer protection in the trachea and lungs, but protection was reduced in the upper airways. In contrast, the monovalent Prototype vaccine no longer offered good protection, and breakthrough infections were observed in all animals and tissues. Thus, the protein-based XBB.1.5 vaccine is immunogenic and can protect against the Omicron EG.5.1 variant in the Syrian hamster model.

VA Big Data Science: A Model for Improved National Pandemic Response Present and Future

Background

The US Department of Veterans Affairs (VA) enterprise approach to research (VA Research) has built a data-sharing framework available to all research teams within VA. Combined with robust analytic systems and tools available for investigators, VA Research has produced actionable results during the COVID-19 pandemic. Big data science techniques applied to VA's health care data demonstrate that medical research can be performed quickly and judiciously during nationwide health care emergencies.

Observations

We envision a common framework of data collection, management, and surveillance implemented in partnership with other health care agencies that would capture even broader, actionable, and timely observational data on populations, while providing opportunities for enhanced collaborative research across agencies. This model should be continued and expanded through the current COVID-19 and future pandemics.

Conclusions

Extending the achievements of VA Research in the COVID-19 pandemic to date, we advocate national goals of open science by working toward a synergistic national framework of anonymized, synchronized, shared health data that would provide researchers with potent tools to combat future public health crises.

Evaluation of the Effects of Coronavirus Vaccination Status on Inpatient Demographics and Clinical and Laboratory Data

Background The coronavirus disease 2019 (COVID-19) pandemic has been largely controlled by vaccines. However, a notable increase in COVID-19 infections has been observed among vaccinated individuals. The protection conferred by vaccination remains a topic of ongoing discussion and research. Our study aims to assess the impact of vaccination status on the demographics, clinical presentations, and laboratory characteristics of patients who were admitted to the hospital and subsequently hospitalized for further evaluation and treatment. Methods We examined hospitalized COVID-19 patients in terms of demographics, immunization status, clinical and laboratory findings, and outcomes over a seven-month period during which the delta variant was prevalent. Patients were categorized into three groups based on their vaccination status: unvaccinated (n=1,321, 53.3%), partially vaccinated (n=214, 8.6%), and fully vaccinated (n=944, 38.1%). Data from these patients were compared across groups. Results The study included 2,479 polymerase chain reaction (PCR)-confirmed hospitalized COVID-19 patients. The median ages (range) for the unvaccinated, partially vaccinated, and fully vaccinated patients who required hospitalization due to COVID-19 infection were 51 (18-98), 61 (21-91), and 71 (23-99), respectively (p<0.001). White blood cell count, neutrophils, monocytes, platelet count, and inflammatory markers such as erythrocyte sedimentation rate, C-reactive protein, procalcitonin, and IL-6, as well as fibrinogen and troponin T levels, were observed to be higher in the fully vaccinated patients compared to the unvaccinated and partially vaccinated patients. Clinical follow-ups showed that the intensive care unit (ICU) admission rates, length of hospital stay, and mortality rates were also higher in the fully vaccinated group compared to the other groups. Conclusion Our findings indicate that full vaccination significantly reduces hospitalization rates in younger individuals with average risk. However, patients with high-risk factors, such as advanced age and multiple comorbidities, exhibited higher hospitalization rates, increased need for intensive care, longer hospital stays, elevated inflammatory markers, and higher mortality even when fully vaccinated. It is crucial for elderly patients to receive thorough evaluations during emergency visits and to be provided with early treatment to reduce potential morbidity and mortality.

mRNA vaccines against respiratory viruses

PURPOSE OF REVIEW

The successes of the coronavirus disease 2019 (COVID-19) mRNA vaccines have accelerated the development of mRNA vaccines against other respiratory pathogens. The aim of this review is to highlight COVID-19 mRNA vaccine advances and provide an update on the progress of mRNA vaccine development against other respiratory pathogens.

RECENT FINDINGS

The COVID-19 mRNA vaccines demonstrated effectiveness in preventing severe COVID-19 and death. H7N9 and H10N8 avian influenza mRNA vaccines have demonstrated safety and immunogenicity in phase 1 clinical trials. Numerous seasonal influenza mRNA vaccines are in phase 1-3 clinical trials. Respiratory syncytial virus (RSV) mRNA vaccines have progressed to phase 2-3 clinical trials in adults and a phase 1 clinical trial in children. A combined human metapneumovirus and parainfluenza-3 mRNA vaccines was found to be well tolerated and immunogenic in a phase 1 trial among adults and trials are being conducted among children. Clinical trials of mRNA vaccines combining antigens from multiple respiratory viruses are underway.

SUMMARY

The development of mRNA vaccines against respiratory viruses has progressed rapidly in recent years. Promising vaccine candidates are moving through the clinical development pathway to test their efficacy in preventing disease against respiratory viral pathogens.

mRNA vaccination boosts S-specific T cell memory and promotes expansion of CD45RAint TEMRA-like CD8+ T cells in COVID-19 recovered individuals

SARS-CoV-2 infection and mRNA vaccination both elicit spike (S)-specific T cell responses. To analyze how T cell memory from prior infection influences T cell responses to vaccination, we evaluated functional T cell responses in naive and previously infected vaccine recipients. Pre-vaccine S-specific responses are predictive of subsequent CD8+ T cell vaccine-response magnitudes. Comparing baseline with post-vaccination TCRβ repertoires, we observed large clonotypic expansions correlated with the frequency of spike-specific T cells. Epitope mapping the largest CD8+ T cell responses confirms that an HLA-A∗03:01 epitope was highly immunodominant. Peptide-MHC tetramer staining together with mass cytometry and single-cell sequencing permit detailed phenotyping and clonotypic tracking of these S-specific CD8+ T cells. Our results demonstrate that infection-induced S-specific CD8+ T cell memory plays a significant role in shaping the magnitude and clonal composition of the circulating T cell repertoire after vaccination, with mRNA vaccination promoting CD8+ memory T cells to a TEMRA-like phenotype.

Real-time forecasting of COVID-19 spread according to protective behavior and vaccination: autoregressive integrated moving average models

BACKGROUND

Mathematical and statistical models are used to predict trends in epidemic spread and determine the effectiveness of control measures. Automatic regressive integrated moving average (ARIMA) models are used for time-series forecasting, but only few models of the 2019 coronavirus disease (COVID-19) pandemic have incorporated protective behaviors or vaccination, known to be effective for pandemic control.

METHODS

To improve the accuracy of prediction, we applied newly developed ARIMA models with predictors (mask wearing, avoiding going out, and vaccination) to forecast weekly COVID-19 case growth rates in Canada, France, Italy, and Israel between January 2021 and March 2022. The open-source data was sourced from the YouGov survey and Our World in Data. Prediction performance was evaluated using the root mean square error (RMSE) and the corrected Akaike information criterion (AICc).

RESULTS

A model with mask wearing and vaccination variables performed best for the pandemic period in which the Alpha and Delta viral variants were predominant (before November 2021). A model using only past case growth rates as autoregressive predictors performed best for the Omicron period (after December 2021). The models suggested that protective behaviors and vaccination are associated with the reduction of COVID-19 case growth rates, with booster vaccine coverage playing a particularly vital role during the Omicron period. For example, each unit increase in mask wearing and avoiding going out significantly reduced the case growth rate during the Alpha/Delta period in Canada (-0.81 and -0.54, respectively; both p < 0.05). In the Omicron period, each unit increase in the number of booster doses resulted in a significant reduction of the case growth rate in Canada (-0.03), Israel (-0.12), Italy (-0.02), and France (-0.03); all p < 0.05.

CONCLUSIONS

The key findings of this study are incorporating behavior and vaccination as predictors led to accurate predictions and highlighted their significant role in controlling the pandemic. These models are easily interpretable and can be embedded in a "real-time" schedule with weekly data updates. They can support timely decision making about policies to control dynamically changing epidemics.

COVID-19 hospitalized patients and oral changes: a case-control study

OBJECTIVES

To investigate the association between hospitalization for COVID-19 and oral changes, and to evaluate whether oral changes can indicate a higher risk of disease progression to death.

MATERIALS AND METHODS

This case-control study analyzed patients hospitalized (university hospital), including those in intensive care unit and clinical wards. The study group comprised 69 COVID-19 positive patients (PCR-test), while the control group included 43 COVID-19 negative patients. A dentist performed oral evaluations, and salivary samples were collected for calcium, phosphatase, and pH analysis. Sociodemographic data, hospitalization information, and hematological test results were collected from electronic-medical records. The presence of oral changes was assessed using chi-square tests, and the predicted risk of death was analyzed using binary logistic regression.

RESULTS

COVID-19 positive patients had a significantly higher prevalence of oral changes compared to COVID-19 negative patients. The presence of any oral changes in COVID-19 positive patients indicated a 13-fold higher risk of mortality. "Bleeding ulcers," "pressure ulcers," and "angular cheilitis" were significantly associated with hospitalization for COVID-19.

CONCLUSION

There may be an association between hospitalization for COVID-19 and the development of oral changes, including bleeding ulcers, pressure ulcers. and angular cheilitis. These oral changes may serve as potential indicator for disease progression an increased risk of death.

CLINICAL RELEVANCE

COVID-19 hospitalized patients have a higher prevalence of oral changes, which indicate an increased risk of mortality. Oral medicine staff should be included in multidisciplinary teams to detect and treat these oral changes promptly.

Early Outcomes of SARS-CoV-2 Infection in a Multisite Prospective Cohort of Inpatient Veterans

Background

Over 870 000 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections have occurred among Veterans Health Administration users, and 24 000 have resulted in death. We examined early outcomes of SARS-CoV-2 infection in hospitalized veterans.

Methods

In an ongoing, prospective cohort study, we enrolled veterans age ≥18 tested for SARS-CoV-2 and hospitalized at 15 Department of Veterans Affairs medical centers between February 2021 and June 2022. We estimated adjusted odds ratios (aORs), adjusted incidence rate ratios (aIRRs), and adjusted hazard ratios (aHRs) for maximum illness severity within 30 days of study entry (defined using the 4-category VA Severity Index for coronavirus disease 2019 [COVID-19]), as well as length of hospitalization and rehospitalization within 60 days, in relationship with demographic characteristics, Charlson comorbidity index (CCI), COVID-19 vaccination, and calendar period of enrollment.

Results

The 542 participants included 329 (61%) who completed a primary vaccine series (with or without booster; "vaccinated"), 292 (54%) enrolled as SARS-CoV-2-positive, and 503 (93%) men, with a mean age of 64.4 years. High CCI scores (≥5) occurred in 61 (44%) vaccinated and 29 (19%) unvaccinated SARS-CoV-2-positive participants. Severe illness or death occurred in 29 (21%; 6% died) vaccinated and 31 (20%; 2% died) unvaccinated SARS-CoV-2-positive participants. SARS-CoV-2-positive inpatients per unit increase in CCI had greater multivariable-adjusted odds of severe illness (aOR, 1.21; 95% CI, 1.01-1.45), more hospitalization days (aIRR, 1.06; 95% CI, 1.03-1.10), and rehospitalization (aHR, 1.07; 95% CI, 1.01-1.12).

Conclusions

In a cohort of hospitalized US veterans with SARS-CoV-2 infection, those with a higher CCI had more severe COVID-19 illness, more hospital days, and rehospitalization, after adjusting for vaccination status, age, sex, and calendar period.

Effectiveness of the Pfizer-BioNTech Vaccine against COVID-19-Associated Hospitalizations among Lebanese Adults ≥75 Years Old-Lebanon, April-May 2021

In Lebanon, the nationwide vaccination against COVID-19 was launched in February 2021 using the Pfizer-BioNTech vaccine and prioritizing elderly people, persons with comorbidities, and healthcare workers. Our study aims to estimate the post-introduction vaccine effectiveness (VE) of the Pfizer-BioNTech vaccine in preventing COVID-19 hospitalizations among elderly people ≥75 years old in Lebanon. A case-control study design was used. Case patients were Lebanese, ≥75 years old, and hospitalized with positive PCR results during April-May 2021, and randomly selected from the database of the Epidemiological Surveillance Unit at the Ministry of Public Health (MOPH). Each case patient was matched by age and locality to two controls. The controls were hospitalized, non-COVID-19 patients, randomly selected from the MOPH hospital admission database. VE was calculated for fully (2 doses ≥14 days) and partially vaccinated (≥14 days of the first or within 14 days of the second dose) participants using multivariate logistic regression. A total of 345 case patients and 814 controls were recruited. Half were females, with a mean age of 83 years. A total of 14 case patients (5%) and 143 controls (22%) were fully vaccinated. A bivariate analysis showed a significant association with gender, month of confirmation/hospital admission, general health, chronic medical conditions, main income source, and living arrangement. After adjusting for a month of hospital admission and gender, the multivariate analysis yielded a VE of 82% (95% CI = 69-90%) against COVID-19-associated hospitalizations for those fully vaccinated and 53% (95% CI = 23-71%) for those partially vaccinated. Our study shows that the Pfizer-BioNTech vaccine is effective in reducing the risk for COVID-19-associated hospitalizations of Lebanese elderly people (≥75 years old). Additional studies are warranted to explore VE in reducing hospitalizations for younger age groups, as well as reducing COVID-19 infections.

Exposure of progressive immune dysfunction by SARS-CoV-2 mRNA vaccination in patients with chronic lymphocytic leukemia: A prospective cohort study

BACKGROUND

Patients with chronic lymphocytic leukemia (CLL) have reduced seroconversion rates and lower binding antibody (Ab) and neutralizing antibody (NAb) titers than healthy individuals following Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) mRNA vaccination. Here, we dissected vaccine-mediated humoral and cellular responses to understand the mechanisms underlying CLL-induced immune dysfunction.

METHODS AND FINDINGS

We performed a prospective observational study in SARS-CoV-2 infection-naïve CLL patients (n = 95) and healthy controls (n = 30) who were vaccinated between December 2020 and June 2021. Sixty-one CLL patients and 27 healthy controls received 2 doses of the Pfizer-BioNTech BNT162b2 vaccine, while 34 CLL patients and 3 healthy controls received 2 doses of the Moderna mRNA-1273 vaccine. The median time to analysis was 38 days (IQR, 27 to 83) for CLL patients and 36 days (IQR, 28 to 57) for healthy controls. Testing plasma samples for SARS-CoV-2 anti-spike and receptor-binding domain Abs by enzyme-linked immunosorbent assay (ELISA), we found that all healthy controls seroconverted to both antigens, while CLL patients had lower response rates (68% and 54%) as well as lower median titers (23-fold and 30-fold; both p < 0.001). Similarly, NAb responses against the then prevalent D614G and Delta SARS-CoV-2 variants were detected in 97% and 93% of controls, respectively, but in only 42% and 38% of CLL patients, who also exhibited >23-fold and >17-fold lower median NAb titers (both p < 0.001). Interestingly, 26% of CLL patients failed to develop NAbs but had high-titer binding Abs that preferentially reacted with the S2 subunit of the SARS-CoV-2 spike. Since these patients were also seropositive for endemic human coronaviruses (HCoVs), these responses likely reflect cross-reactive HCoV Abs rather than vaccine-induced de novo responses. CLL disease status, advanced Rai stage (III-IV), elevated serum beta-2 microglobulin levels (β2m >2.4 mg/L), prior therapy, anti-CD20 immunotherapy (<12 months), and intravenous immunoglobulin (IVIg) prophylaxis were all predictive of an inability to mount SARS-CoV-2 NAbs (all p ≤ 0.03). T cell response rates determined for a subset of participants were 2.8-fold lower for CLL patients compared to healthy controls (0.05, 95% CI 0.01 to 0.27, p < 0.001), with reduced intracellular IFNγ staining (p = 0.03) and effector polyfunctionality (p < 0.001) observed in CD4+ but not in CD8+ T cells. Surprisingly, in treatment-naïve CLL patients, BNT162b2 vaccination was identified as an independent negative risk factor for NAb generation (5.8, 95% CI 1.6 to 27, p = 0.006). CLL patients who received mRNA-1273 had 12-fold higher (p < 0.001) NAb titers and 1.7-fold higher (6.5, 95% CI 1.3 to 32, p = 0.02) response rates than BNT162b2 vaccinees despite similar disease characteristics. The absence of detectable NAbs in CLL patients was associated with reduced naïve CD4+ T cells (p = 0.03) and increased CD8+ effector memory T cells (p = 0.006). Limitations of the study were that not all participants were subjected to the same immune analyses and that pre-vaccination samples were not available.

CONCLUSIONS

CLL pathogenesis is characterized by a progressive loss of adaptive immune functions, including in most treatment-naïve patients, with preexisting memory being preserved longer than the capacity to mount responses to new antigens. In addition, higher NAb titers and response rates identify mRNA-1273 as a superior vaccine for CLL patients.

Severe acute respiratory coronavirus virus 2 (SARS-CoV-2) outbreaks in nursing homes involving residents who had completed a primary coronavirus disease 2019 (COVID-19) vaccine series-13 US jurisdictions, July-November 2021

Among nursing home outbreaks of coronavirus disease 2019 (COVID-19) with ≥3 breakthrough infections when the predominant severe acute respiratory coronavirus virus 2 (SARS-CoV-2) variant circulating was the SARS-CoV-2 δ (delta) variant, fully vaccinated residents were 28% less likely to be infected than were unvaccinated residents. Once infected, they had approximately half the risk for all-cause hospitalization and all-cause death compared with unvaccinated infected residents.

Humoral Immune Response after COVID-19 mRNA Vaccination in Patients with Liver Cirrhosis: A Prospective Real-Life Single Center Study

Coronavirus-disease-2019 (COVID-19) mRNA vaccination effectively reduces mortality and morbidity in cirrhotic patients, but the immunogenicity and safety of vaccination have been partially characterized. The study aimed to evaluate humoral response, predictive factors, and safety of mRNA-COVID-19 vaccination in cirrhotic patients compared to healthy subjects. A prospective, single-center, observational study enrolled consecutive cirrhotic patients who underwent mRNA-COVID-19 vaccination from April to May 2021. Anti-spike-protein (anti-S) and nucleocapsid-protein (anti-N) antibodies were evaluated before the first (T0) and the second (T1) doses and 15 days after completing the vaccination. An age and sex-matched healthy reference group was included. The incidence of adverse events (AEs) was assessed. In total, 162 cirrhotic patients were enrolled, 13 were excluded due to previous SARS-CoV-2 infection; therefore, 149 patients and 149 Health Care Workers (HCWs) were included in the analysis. The seroconversion rate was similar in cirrhotic patients and HCWs at T1 (92.5% vs. 95.3%, p = 0.44) and T2 (100% in both groups). At T2, anti-S-titres were significantly higher in cirrhotic patients compared to HCWs (2776.6 vs. 1756 BAU/mL, p < 0.001]. Male sex (β = -0.32 [-0.64, -0.04], p = 0.027) and past-HCV-infection (β = -0.31 [-0.59, -0.04], p = 0.029) were independent predictors of lower anti-S-titres on multiple-gamma-regression-analysis. No severe AEs occurred. The COVID-19-mRNA vaccination induces a high immunization rate and anti-S-titres in cirrhotic patients. Male sex and past-HCV infection are associated with lower anti-S-titres. The COVID-19-mRNA vaccination is safe.

The impact of the COVID-19 pandemic on individuals with Fontan circulation: Focus on gaps in care

Background

Gaps in subspecialty cardiology care could potentially delay identification and care for multi-organ complications common in patients with Fontan circulation. This study analyzed the frequency of gaps in care for individuals with Fontan circulation during the COVID-19 pandemic and associated demographic and clinical factors.

Methods

This retrospective study evaluated individuals with Fontan circulation followed at our center since 2010. A gap in care was defined as an absence of any formal cardiology provider-patient contact (clinic visit or telehealth) for >15 months.

Results

Over a third of 308 patients with Fontan circulation experienced at least one gap in care between 2010 and 2022, and 77 experienced a gap in care during the COVID-19 pandemic. Of this latter group, 27 (35%) had never experienced a prior gap in cardiology care until the pandemic. Those who experienced gaps in care during the pandemic were on average older (18.0 [IQR 9.6-25.6] vs. 14.2 [7.2-21.2] years, p = 0.01), more likely to be of Black/African American race (23.4% vs 7.4%, p = 0.001), and less likely to have a diagnosis of protein-losing enteropathy or plastic bronchitis (0% vs. 8.6%, p = 0.005). Those without a gap in care during the pandemic were more likely to have utilized telehealth visits (13% vs 3%, p = 0.02).

Conclusion

Gaps in care are common and appear to have been exacerbated by the COVID-19 pandemic in those with a Fontan circulation. Such gaps are particularly common among African American and adult patients, and may potentially be mitigated by expanding telehealth access.

Patient-Reported Outcomes for Fully Vaccinated COVID-19 Patients Over 6 Weeks: The Experiences of Clinical Breakthrough Cases

BACKGROUND

While coronavirus disease 2019 (COVID-19) vaccines have high rates of efficacy, fully vaccinated individuals can become infected with COVID-19. Among this population, symptoms tend to be less severe and shorter lasting. Less is known about how vaccinated individuals who contract COVID-19 experience the disease through patient-reported outcomes (PROs) and how this changes over time.

OBJECTIVE

The aim of this study was to describe the physical, mental, and social health PROs for fully vaccinated individuals who contracted COVID-19 over a 6-week period.

DESIGN

Prospective design using the Patient-Reported Outcomes Measurement Information System short-form (PROMIS-10) collected through a mobile application-based platform.

PARTICIPANT

1114 fully vaccinated patients who tested positive for COVID-19 at a large US health system and engaged with the study on or after 1 March 2021 and reported onset of illness prior to 1 November 2021.

MAIN MEASURES

Global physical and mental health PROMIS-10 T-scores for the 6-week period, component PROMIS-10 questions for the 6-week period, and component PROMIS-10 questions restricted to a subset of participants for the first month to measure individual recovery were analyzed.

KEY RESULTS

Mean global physical and mental health T-scores increased over time and remained within one standard deviation of the population mean. At baseline, at least 40% of participants reported good health for all component questions except Fatigue (25%), and the proportion reporting good health increased over time for all questions, with the largest improvements in Fatigue (25.5 to 67.5%), Pain (59.1 to 82.8%), and Emotional Problems (42.3 to 62.5%). Over the first month, the greatest positive changes in individual recovery were observed for Fatigue (65.0%), Pain (53.0%), and Emotional Problems (41.1%); at least 30% of respondents reported no change in at least one category, and the greatest decreases were for Usual Social Activities (23.9%), Social Satisfaction (23.2%), and Mental Health (21.8%).

CONCLUSIONS

This study provides an important step towards better understanding the impact of 'breakthrough' COVID-19 infections on clinically engaged, fully vaccinated patients' physical and mental health to improve support for their treatment and recovery.

Modelling pandemic risks for policy analysis and forecasting

What were the economic effects of vaccination campaign, agents' adaptation to containment measures, and fiscal and monetary measures during the COVID-19 pandemic? To quantify these effects, we augment the ECB's macro-econometric model with an endogenous epidemiological block, providing one of the first institutional policy models with epidemiological elements. The model tracks closely actual pandemic developments by relying on detailed epidemiological data and by nesting a wide range of features, including vaccination campaigns, emergence of new variants and learning effects. Importantly, it includes an endogenous policy reaction function for containment measures, allowing counterfactual simulations. Our simulation results show that: (i) agents' adaptation to containment measures over time was key in reducing negative macroeconomic consequences of lockdowns, (ii) the vaccination campaign slowed down infection rates and hospitalizations, enabling a relaxation of containment measures and avoiding a sharp double dip in economic activity and (iii) complementary fiscal and monetary policy interventions provided support to the economy.

Frailty Reduces Vaccine Effectiveness Against SARS-CoV-2 Infection: A Test-Negative Case Control Study Using National VA Data

OBJECTIVES

To assess the variation of vaccine effectiveness against SARS-CoV-2 infection during the Delta wave according to frailty status among U.S. veterans.

DESIGN

Test-negative case-control study of SARS-CoV-2 mRNA vaccine effectiveness.

SETTING

Veterans Health Administration (VHA) medical centers.

PARTICIPANTS

Veterans 19 years and older who had at least one COVID-19/Flu like symptoms and received a SARS-CoV-2 PCR or antigen test at VHA medical centers between July 25 to September 30, 2021.

INTERVENTION

mRNA vaccination.

MEASUREMENTS

New SARS-CoV-2 infection. Vaccine effectiveness was defined as 1-odds of vaccination in cases/odds of vaccination in controls, where cases were patients who had a COVID-19 test and tested positive for SARS-CoV-2, and controls were those who tested negative. Frailty was measured using the VA frailty index, categorized as robust (0-<0.1), pre-frail (≥0.1-<0.21) and frail (≥0.21).

RESULTS

A total of 58,604 patients (age:58.9±17.0, median:61, IQR:45-72; 87.5%men; 68.1%white; 1.3%African American, 8.3%Hispanic) were included in the study. Of these, 27,733 (47.3%) were robust, 16,276 (27.8%) were prefrail, and 14,595 (24.9%) were frail. mRNA vaccine effectiveness against the Delta variant symptomatic infection was lower in patients with frailty, 62.8 %(95%CI:59.8-65.7), versus prefrail 73.9%(95%CI:72.0-75.7), and robust, 77.0 %(95%CI:75.7-78.3).

CONCLUSIONS

This test-negative case control study showed that mRNA vaccine effectiveness against infection declined in veterans with frailty. Frailty status is a factor to consider when designing, developing, and evaluating COVID-19 vaccines.

SARS-CoV-2 Infection, Hospitalization, and Death in Vaccinated and Infected Individuals by Age Groups in Indiana, 2021‒2022

Objectives. To assess the effectiveness of vaccine-induced immunity against new infections, all-cause emergency department (ED) and hospital visits, and mortality in Indiana. Methods. Combining statewide testing and immunization data with patient medical records, we matched individuals who received at least 1 dose of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines with individuals with previous SARS-CoV-2 infection on index date, age, gender, race/ethnicity, zip code, and clinical diagnoses. We compared the cumulative incidence of infection, all-cause ED visits, hospitalizations, and mortality. Results. We matched 267 847 pairs of individuals. Six months after the index date, the incidence of SARS-CoV-2 infection was significantly higher in vaccine recipients (6.7%) than the previously infected (2.9%). All-cause mortality in the vaccinated, however, was 37% lower than that of the previously infected. The rates of all-cause ED visits and hospitalizations were 24% and 37% lower in the vaccinated than in the previously infected. Conclusions. The significantly lower rates of all-cause ED visits, hospitalizations, and mortality in the vaccinated highlight the real-world benefits of vaccination. The data raise questions about the wisdom of reliance on natural immunity when safe and effective vaccines are available. (Am J Public Health. 2023;113(1):96-104. https://doi.org/10.2105/AJPH.2022.307112).

Waning effectiveness of SARS-CoV-2 mRNA vaccines in older adults: a rapid review

The U.S. Centers for Disease Control and Prevention (CDC) and other health agencies have recently recommended a booster dose of COVID-19 vaccines for specific vulnerable groups including adults 65 years and older. There is limited evidence whether vaccine effectiveness (VE) in older adults decreases over time, especially against severe COVID-19. We performed a rapid review of published studies available through 4 November 2021 that provide effectiveness data on messenger RNA (mRNA) vaccines approved/licensed in the United States and identified eight eligible studies which evaluated VE in older adults. There is evidence of a decline in VE against both severe acute respiratory syndrome coronavirus 2 infection and severe COVID-19 in older adults among studies which analyzed data up to July-October 2021. Our findings suggest that VE diminishes in older adults, which supports the current recommendation for a booster dose in this population.

Assessment of COVID-19 vaccination among healthcare workers in Iraq; adverse effects and hesitancy

Several messenger ribonucleic acid (mRNA) and inactivated COVID-19 vaccines are available to the global population as of 2022. The acceptance of the COVID-19 vaccine will play a key role in combating the worldwide pandemic. Public confidence in this vaccine is largely based on its safety and effectiveness. This study was designed to provide independent evidence of the adverse effects associated with COVID-19 vaccines among healthcare workers in Iraq and to identify the attitudes of healthcare workers who rejected the vaccination. We conducted a cross-sectional study to collect data on the adverse effects of the Pfizer, AstraZeneca, and Sinopharm vaccines. Data were collected between October 2021 and February 2022. A total of 2,202 participants were enrolled in the study: (89.97%) received injections of the COVID-19 vaccines and (10.03%) were hesitant to receive the vaccination. Participants received either the Pfizer vaccine (62.9%), AstraZeneca vaccine (23.5%) or Sinopharm vaccine (13.6%). Most adverse effects were significantly less prevalent in the second dose than in the first dose. Notably, the adverse effects associated with the Pfizer vaccine were significantly more prevalent in females than in males. Following the first dose, the participants experienced more adverse effects with the AstraZeneca vaccine. Following the second dose, more adverse effects were associated with the Pfizer vaccine. Interestingly, the prevalence of COVID-19 infection in participants who received two doses of the Pfizer vaccine was significantly reduced compared to those who received two doses of either the AstraZeneca or Sinopharm vaccines. According to vaccine-hesitated participants, insufficient knowledge (29.9%), expeditious development (27.6%) and lack of trust in the vaccines (27.1%) were the three major reasons for refusing the vaccines. The results of our study indicated that these adverse effects do not present a significant problem and should not prevent successful control of the COVID-19 pandemic.

Evaluating methodological approaches to assess the severity of infection with SARS-CoV-2 variants: scoping review and applications on Belgian COVID-19 data

Background

Differences in the genetic material of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants may result in altered virulence characteristics. Assessing the disease severity caused by newly emerging variants is essential to estimate their impact on public health. However, causally inferring the intrinsic severity of infection with variants using observational data is a challenging process on which guidance is still limited. We describe potential limitations and biases that researchers are confronted with and evaluate different methodological approaches to study the severity of infection with SARS-CoV-2 variants.

Methods

We reviewed the literature to identify limitations and potential biases in methods used to study the severity of infection with a particular variant. The impact of different methodological choices is illustrated by using real-world data of Belgian hospitalized COVID-19 patients.

Results

We observed different ways of defining coronavirus disease 2019 (COVID-19) disease severity (e.g., admission to the hospital or intensive care unit versus the occurrence of severe complications or death) and exposure to a variant (e.g., linkage of the sequencing or genotyping result with the patient data through a unique identifier versus categorization of patients based on time periods). Different potential selection biases (e.g., overcontrol bias, endogenous selection bias, sample truncation bias) and factors fluctuating over time (e.g., medical expertise and therapeutic strategies, vaccination coverage and natural immunity, pressure on the healthcare system, affected population groups) according to the successive waves of COVID-19, dominated by different variants, were identified. Using data of Belgian hospitalized COVID-19 patients, we were able to document (i) the robustness of the analyses when using different variant exposure ascertainment methods, (ii) indications of the presence of selection bias and (iii) how important confounding variables are fluctuating over time.

Conclusions

When estimating the unbiased marginal effect of SARS-CoV-2 variants on the severity of infection, different strategies can be used and different assumptions can be made, potentially leading to different conclusions. We propose four best practices to identify and reduce potential bias introduced by the study design, the data analysis approach, and the features of the underlying surveillance strategies and data infrastructure.

Incidence of Severe COVID-19 Illness Following Vaccination and Booster With BNT162b2, mRNA-1273, and Ad26.COV2.S Vaccines

Importance

Evidence describing the incidence of severe COVID-19 illness following vaccination and booster with BNT162b2, mRNA-1273, and Ad26.COV2.S vaccines is needed, particularly for high-risk populations.

Objective

To describe the incidence of severe COVID-19 illness among a cohort that received vaccination plus a booster vaccine dose.

Design, Setting, and Participants

Retrospective cohort study of adults receiving care at Veterans Health Administration facilities across the US who received a vaccination series plus 1 booster against SARS-CoV-2, conducted from July 1, 2021, to May 30, 2022. Patients were eligible if they had received a primary care visit in the prior 2 years and had documented receipt of all US Food and Drug Administration-authorized doses of the initial mRNA vaccine or viral vector vaccination series after December 11, 2020, and a subsequent documented booster dose between July 1, 2021, and April 29, 2022. The analytic cohort consisted of 1 610 719 participants.

Exposures

Receipt of any combination of mRNA-1273 (Moderna), BNT162b2 (Pfizer-BioNTech), and Ad26.COV2.S (Janssen/Johnson & Johnson) primary vaccination series and a booster dose.

Main Outcomes and Measures

Outcomes were breakthrough COVID-19 (symptomatic infection), hospitalization with COVID-19 pneumonia and/or death, and hospitalization with severe COVID-19 pneumonia and/or death. A subgroup analysis of nonoverlapping populations included those aged 65 years or older, those with high-risk comorbid conditions, and those with immunocompromising conditions.

Results

Of 1 610 719 participants, 1 100 280 (68.4%) were aged 65 years or older and 132 243 (8.2%) were female; 1 133 785 (70.4%) had high-risk comorbid conditions, 155 995 (9.6%) had immunocompromising conditions, and 1 467 879 (91.1%) received the same type of mRNA vaccine (initial series and booster). Over 24 weeks, 125.0 (95% CI, 123.3-126.8) per 10 000 persons had breakthrough COVID-19, 8.9 (95% CI, 8.5-9.4) per 10 000 persons were hospitalized with COVID-19 pneumonia or died, and 3.4 (95% CI, 3.1-3.7) per 10 000 persons were hospitalized with severe pneumonia or died. For high-risk populations, incidence of hospitalization with COVID-19 pneumonia or death was as follows: aged 65 years or older, 1.9 (95% CI, 1.4-2.6) per 10 000 persons; high-risk comorbid conditions, 6.7 (95% CI, 6.2-7.2) per 10 000 persons; and immunocompromising conditions, 39.6 (95% CI, 36.6-42.9) per 10 000 persons. Subgroup analyses of patients hospitalized with COVID-19 pneumonia or death by time after booster demonstrated similar incidence estimates among those aged 65 years or older and with high-risk comorbid conditions but not among those with immunocompromising conditions.

Conclusions and Relevance

In a US cohort of patients receiving care at Veterans Health Administration facilities during a period of Delta and Omicron variant predominance, there was a low incidence of hospitalization with COVID-19 pneumonia or death following vaccination and booster with any of BNT162b2, mRNA-1273, or Ad26.COV2.S vaccines.

Sarcoidosis and COVID-19: At the Cross-Road between Immunopathology and Clinical Manifestation

Coronavirus disease 2019 (COVID-19) has been associated with dysregulation of the immune system featuring inappropriate immune responses, exacerbation of inflammatory responses, and multiple organ dysfunction syndrome in patients with severe disease. Sarcoidosis, also known as Besnier-Boeck-Schaumann disease, is an idiopathic granulomatous multisystem disease characterized by dense epithelioid non-necrotizing lesions with varying degrees of lymphocytic inflammation. These two diseases have similar clinical manifestations and may influence each other at multiple levels, eventually affecting their clinical courses and prognosis. Notably, sarcoidosis patients are at high risk of severe COVID-19 pneumonia because of the underlying lung disease and chronic immunosuppressive treatment. In this narrative review, we will discuss interactions between sarcoidosis and COVID-19 in terms of clinical manifestations, treatment, and pathogenesis, including the role of the dysregulated renin-angiotensin system, altered immune responses involving increased cytokine levels and immune system hyperactivation, and cellular death pathways.

COVID-19-Associated Hospitalizations Among Vaccinated and Unvaccinated Adults 18 Years or Older in 13 US States, January 2021 to April 2022

Importance

Understanding risk factors for hospitalization in vaccinated persons and the association of COVID-19 vaccines with hospitalization rates is critical for public health efforts to control COVID-19.

Objective

To determine characteristics of COVID-19-associated hospitalizations among vaccinated persons and comparative hospitalization rates in unvaccinated and vaccinated persons.

Design, Setting, and Participants

From January 1, 2021, to April 30, 2022, patients 18 years or older with laboratory-confirmed SARS-CoV-2 infection were identified from more than 250 hospitals in the population-based COVID-19-Associated Hospitalization Surveillance Network. State immunization information system data were linked to cases, and the vaccination coverage data of the defined catchment population were used to compare hospitalization rates in unvaccinated and vaccinated individuals. Vaccinated and unvaccinated patient characteristics were compared in a representative sample with detailed medical record review; unweighted case counts and weighted percentages were calculated.

Exposures

Laboratory-confirmed COVID-19-associated hospitalization, defined as a positive SARS-CoV-2 test result within 14 days before or during hospitalization.

Main Outcomes and Measures

COVID-19-associated hospitalization rates among vaccinated vs unvaccinated persons and factors associated with COVID-19-associated hospitalization in vaccinated persons were assessed.

Results

Using representative data from 192 509 hospitalizations (see Table 1 for demographic information), monthly COVID-19-associated hospitalization rates ranged from 3.5 times to 17.7 times higher in unvaccinated persons than vaccinated persons regardless of booster dose status. From January to April 2022, when the Omicron variant was predominant, hospitalization rates were 10.5 times higher in unvaccinated persons and 2.5 times higher in vaccinated persons with no booster dose, respectively, compared with those who had received a booster dose. Among sampled cases, vaccinated hospitalized patients with COVID-19 were older than those who were unvaccinated (median [IQR] age, 70 [58-80] years vs 58 [46-70] years, respectively; P < .001) and more likely to have 3 or more underlying medical conditions (1926 [77.8%] vs 4124 [51.6%], respectively; P < .001).

Conclusions and Relevance

In this cross-sectional study of US adults hospitalized with COVID-19, unvaccinated adults were more likely to be hospitalized compared with vaccinated adults; hospitalization rates were lowest in those who had received a booster dose. Hospitalized vaccinated persons were older and more likely to have 3 or more underlying medical conditions and be long-term care facility residents compared with hospitalized unvaccinated persons. The study results suggest that clinicians and public health practitioners should continue to promote vaccination with all recommended doses for eligible persons.

Effectiveness of Pfizer/BioNTech and Sinopharm COVID-19 vaccines in reducing hospital admissions in prince Hamza hospital, Jordan

Background

There is a need to establish the effectiveness of the coronavirus disease 2019 (COVID-19) vaccines in reducing COVID-19-related hopitalization of patients in Jordan. As the vaccination program accelerates, it is important to determine whether the vaccines' effectiveness (VE) has successfully reduced the number of acute cases admitted to hospital.

Methods

To determine the efficacy of Pfizer-BioNTech and Sinopharm COVID-19 vaccines among Jordanian patients admitted to Prince Hamza hospital, a single center case-control study was performed. The study analyzed the hospitalization rates of vaccinated (n = 536) and unvaccinated (n = 585) individuals across the 2-month period from February 6 to April 6, 2022. The cases were patients who tested positive for SARS-CoV-2 ("case-patients"), whilst the control group were hospital patients who did not test positive for SARS-CoV-2 ("control-patients").

Results

This study found that among 1,121 total participants (561 cases and 560 control), the overall vaccine effectiveness (VE) among the participants was 84% (95% Cl 79-88%). VE was higher in females (88%, 95% Cl 84-93%) than in males (77%, 95% Cl 67-84%) (p < 0.001), and it was highest in those between the ages of 18 and 28-years-old (95%, 95% CI 86-98%). For patients with pre-existing conditions, including chronic heart disease, chronic lung disease, and diabetes, VE was higher compared to patients with no comorbidities, though the difference was not statistically significant. Finally, in comparing all vaccinated participants, VE was higher for those who received the Pfizer vaccine (VE = 92%, 95% CI 88-94%) (OR 0.08, 95% CI 0.06-0.12) than for those who received the Sinopharm vaccine (VE = 67%, 95% CI 52-78%) (OR 0.33, 95% CI 0.22-0.48); (p = 0.011).

Conclusion

Overall, Pfizer and Sinopharm vaccines were found to be effective in limiting hospitalizations for acute cases of coronavirus among Jordanian adult's patient's cohort between February 6 and April 6, 2022, especially among patients with comorbidities.

SARS-CoV-2 infection, vaccination, and antibody response trajectories in adults: a cohort study in Catalonia

BACKGROUND

Heterogeneity of the population in relation to infection, COVID-19 vaccination, and host characteristics is likely reflected in the underlying SARS-CoV-2 antibody responses.

METHODS

We measured IgM, IgA, and IgG levels against SARS-CoV-2 spike and nucleocapsid antigens in 1076 adults of a cohort study in Catalonia between June and November 2020 and a second time between May and July 2021. Questionnaire data and electronic health records on vaccination and COVID-19 testing were available in both periods. Data on several lifestyle, health-related, and sociodemographic characteristics were also available.

RESULTS

Antibody seroreversion occurred in 35.8% of the 64 participants non-vaccinated and infected almost a year ago and was related to asymptomatic infection, age above 60 years, and smoking. Moreover, the analysis on kinetics revealed that among all responses, IgG RBD, IgA RBD, and IgG S2 decreased less within 1 year after infection. Among vaccinated, 2.1% did not present antibodies at the time of testing and approximately 1% had breakthrough infections post-vaccination. In the post-vaccination era, IgM responses and those against nucleoprotein were much less prevalent. In previously infected individuals, vaccination boosted the immune response and there was a slight but statistically significant increase in responses after a 2nd compared to the 1st dose. Infected vaccinated participants had superior antibody levels across time compared to naïve-vaccinated people. mRNA vaccines and, particularly the Spikevax, induced higher antibodies after 1st and 2nd doses compared to Vaxzevria or Janssen COVID-19 vaccines. In multivariable regression analyses, antibody responses after vaccination were predicted by the type of vaccine, infection age, sex, smoking, and mental and cardiovascular diseases.

CONCLUSIONS

Our data support that infected people would benefit from vaccination. Results also indicate that hybrid immunity results in superior antibody responses and infection-naïve people would need a booster dose earlier than previously infected people. Mental diseases are associated with less efficient responses to vaccination.

Estimating COVID-19 Vaccination and Booster Effectiveness Using Electronic Health Records From an Academic Medical Center in Michigan

Introduction

Observational studies of COVID-19 vaccines' effectiveness can provide crucial information regarding the strength and durability of protection against SARS-CoV-2 infection and whether the protective response varies across different patient subpopulations and in the context of different SARS-CoV-2 variants.

Methods

We used a test-negative study design to assess vaccine effectiveness against SARS-CoV-2 infection and severe COVID-19 resulting in hospitalization, intensive care unit admission, or death using electronic health records data of 170,741 adults who had been tested for COVID-19 at the University of Michigan Medical Center between January 1 and December 31, 2021. We estimated vaccine effectiveness by comparing the odds of vaccination between cases and controls during each 2021 calendar quarter and stratified all outcomes by vaccine type, patient demographic and clinical characteristics, and booster status.

Results

Unvaccinated individuals had more than double the rate of infections (12.1% vs 4.7%) and >3 times the rate of severe COVID-19 outcomes (1.4% vs 0.4%) than vaccinated individuals. COVID-19 vaccines were 62.1% (95% CI=60.3, 63.8) effective against a new infection, with protection waning in the last 2 quarters of 2021. The vaccine effectiveness against severe disease overall was 73.7% (95% CI=69.6, 77.3) and remained high throughout 2021. Data from the last quarter of 2021 indicated that adding a booster dose augmented effectiveness against infection up to 87.3% (95% CI=85.0, 89.2) and against severe outcomes up to 94.0% (95% CI=89.5, 96.6). Pfizer-BioNTech and Moderna vaccines showed comparable performance when controlling for vaccination timing. Vaccine effectiveness was greater in more socioeconomically affluent areas and among healthcare workers; otherwise, we did not detect any significant modification of vaccine effectiveness by covariates, including gender, race, and SES.

Conclusions

COVID-19 vaccines were highly protective against infection and severe COVID-19 resulting in hospitalization, intensive care unit admission, or death. Administration of a booster dose significantly increased vaccine effectiveness against both outcomes. Ongoing surveillance is required to assess the durability of these findings.

Efficacy of COVID-19 vaccines

As of 2022, the global population has access to several mRNA and traditional inactivated vaccines. However, their effectiveness in preventing infection, hospitalization, and COVID-associated mortality in Jordan has yet to be evaluated. The purpose of this observational study was to evaluate the relative effectiveness of three approved vaccines against COVID-19 in a sample of the Jordanian population. The study was conducted between July 2021 and 2022 in a sample of adult patients presenting to hospitals across Jordan and receiving one of the three vaccines - Pfizer (BNT162b2), Astra Zeneca (ChAdOx1-S), or Sinopharm (BBIBP-CorV). Data were collected to measure the rates of infection without hospitalization, infection with hospitalization, and death. The sample included patients with one of the following chronic conditions: cardiovascular disease, respiratory disease, or diabetes. Primary data were obtained from patients' health records. The sample included 6132 adults from Jordan, with a mean age 52 ± 17 years. The rates of death in patients receiving two doses of any vaccine ranged between 0.175 and 2.77%, compared with 0.69-13.53% in patients receiving only one dose. The rates of hospitalization were 6-7.97% with two doses, compared to 7.98-25.13% with one dose. The rates of infection without hospitalization were significantly higher in the two-dose group (6-25.1%) compared with those who had received only one dose of any COVID-19 vaccine (0.69-10.61%). In conclusion, receiving two doses of a COVID-19 vaccine was associated with lower odds of mortality and hospitalization and higher odds of infection. More research is needed to evaluate the safety and efficacy of vaccines against SARS-CoV-2.

High-resolution analysis of individual spike peptide-specific CD4+ T-cell responses in vaccine recipients and COVID-19 patients

Objectives

Potential differences in the breadth, distribution and magnitude of CD4⁺ T‐cell responses directed against the SARS‐CoV‐2 spike glycoprotein between vaccinees, COVID‐19 patients and subjects who experienced both ways of immunisation have not been comprehensively compared on a peptide level.

Methods

Following virus‐specific in vitro cultivation, we determined the T‐cell responses directed against 253 individual overlapping 15‐mer peptides covering the entire SARS‐CoV‐2 spike glycoprotein using IFN‐γ ELISpot and intracellular cytokine staining. In vitro HLA binding was determined for selected peptides.

Results

We mapped 955 single peptide‐specific CD4⁺ T‐cell responses in a cohort of COVID‐19 patients (n = 8), uninfected vaccinees (n = 16) and individuals who experienced both infection and vaccination (n = 11). Patients and vaccinees (two‐time and three‐time vaccinees alike) had a comparable number of CD4⁺ T‐cell responses (median 26 vs. 29, P = 0.7289). Most of these specificities were conserved in B.1.1.529 and the BA.4 and BA.5 sublineages. The highest magnitude of these in vitro IFN‐γ CD4⁺ T‐cell responses was observed in COVID‐19 patients (median 0.35%), and three‐time vaccinees showed a higher magnitude than two‐time vaccinees (median 0.091% vs. 0.175%, P < 0.0001). Twelve peptide specificities were each detected in at least 40% of subjects. In vitro HLA binding showed promiscuous presentation by DRB1 molecules for several peptides.

Conclusion

Both SARS‐CoV‐2 infection and vaccination prime broadly directed T‐cell responses directed against the SARS‐CoV‐2 spike glycoprotein. This comprehensive high‐resolution analysis of spike peptide specificities will be a useful resource for further investigation of spike‐specific T‐cell responses.

Effectiveness of mRNA COVID-19 vaccines against Omicron and Delta variants in a matched test-negative case-control study among US veterans

OBJECTIVE

To estimate the effectiveness of messenger RNA (mRNA) booster doses during the period of Delta and Omicron variant dominance.

DESIGN

We conducted a matched test-negative case-control study to estimate the vaccine effectiveness (VE) of three and two doses of mRNA vaccines against infection (regardless of symptoms) and against COVID-19-related hospitalisation and death.

SETTING

Veterans Health Administration.

PARTICIPANTS

We used electronic health record data from 114 640 veterans who had a SARS-CoV-2 test during November 2021-January 2022. Patients were largely 65 years or older (52%), male (88%) and non-Hispanic white (59%).

MAIN OUTCOME MEASURES

First positive result for a SARS-CoV-2 PCR or antigen test.

RESULTS

Against infection, booster doses had higher estimated VE (64%, 95% CI 63 to 65) than two-dose vaccination (12%, 95% CI 10 to 15) during the Omicron period. For the Delta period, the VE against infection was 90% (95% CI 88 to 92) among boosted vaccinees, higher than the VE among two-dose vaccinees (54%, 95% CI 50 to 57). Against hospitalisation, booster dose VE was 89% (95% CI 88 to 91) during Omicron and 94% (95% CI 90 to 96) during Delta; two-dose VE was 63% (95% CI 58 to 67) during Omicron and 75% (95% CI 69 to 80) during Delta. Against death, the VE with a booster dose was 94% (95% CI 90 to 96) during Omicron and 96% (95% CI 87 to 99) during Delta.

CONCLUSIONS

Among an older, mostly male, population with comorbidities, we found that an mRNA vaccine booster was highly effective against infection, hospitalisation and death. Although the effectiveness of booster vaccination against infection was moderately higher against Delta than against the Omicron SARS-CoV-2 variant, effectiveness against severe disease and death was similarly high against both variants.

Immunologic response, Efficacy, and Safety of Vaccines against COVID-19 Infection in Healthy and immunosuppressed Children and Adolescents Aged 2 - 21 years old: A Systematic Review and Meta-analysis

Children and adolescents form a large proportion of societies and play an important role in the transmission of COVID-19. On the other hand, their education, mental and physical wellness, and safety are compromised which makes vaccination a crucial step to return to normal life. In the current systematic review, the COVID-19 vaccination was evaluated in a total of 50,148 children and adolescents in 22 published studies and 5,279 participants in two ongoing clinical trials. The study was registered in the PROSPERO with the ID# CRD42022303615. Data were collected about multiple vaccines including BNT162b2 (Pfizer), mRNA-1273 (Moderna), JNJ-78436735 (Johnson and Johnson), CoronaVac (Sinovac), BBIBP-CorV (Sinopharm), adenovirus type-5-vectored vaccine, ZyCov-D, and BBV152 (COVAXIN). The immune response and efficacy of such vaccines were 96% - 100% in healthy children and adolescents and were also acceptable in those with underlying diseases and suppressed immune systems. The current systematic review revealed favorable safety profiles of employed vaccines in children and adolescents; however, adverse reactions such as myocarditis and myopericarditis were reported which were transient and resolved entirely. Consequently, vaccinating children and adolescents aged 2 - 21 years old is beneficial to abort the COVID-19 pandemic. Moreover, the risk-benefit assessments revealed favorable results for vaccinating children and adolescents, especially those with underlying diseases and immunosuppressed conditions, alongside adults to prevent transmission, severe infection, negative outcomes, and new variants formation. Also, according to the meta-analysis, the efficacy and immune response of vaccines after the first and second doses were 91% and 92%, respectively. Meanwhile, overall immune response for all vaccines was 95% and 91% for Pfizer vaccine.

COVID-19 Vaccine Booster Strategies for Omicron SARS-CoV-2 Variant: Effectiveness and Future Prospects

In the light of the lack of authorized COVID-19 vaccines adapted to the Omicron variant lineage, the administration of the first and second booster dose is recommended. It remains important to monitor the efficacy of such an approach in order to inform future preventive strategies. The present paper summarizes the research progress on the effectiveness of the first and second booster doses of COVID-19. It also discusses the potential approach in vaccination strategies that could be undertaken to maintain high levels of protection during the waves of SARS-CoV-2 infections. Although this approach can be based, with some shortcomings, on the first-generation vaccines, other vaccination strategies should be explored, including developing multiple antigen-based (multivariant-adapted) booster doses with enhanced durability of immune protection, e.g., through optimization of the half-life of generated antibodies.

Clinical characteristics and outcome of hospitalized elderly patients with COVID- 19 after vaccine failure

We described clinical characteristics and outcome of 160 patients over 65 years (01 September to 31 August 2021) who had a first positive SARS-CoV-2 PCR- test more than 14 days after full vaccination and were hospitalized with COVID-19. Median age of included patients was 84 years, 61.2% were over 80 years; 50.6% were male and most (82.5%) has at least one comorbidity. Up to 84% received specific treatment against COVID-19, including 76.9% low-flow oxygen therapy. We found that overall mortality was 25.6% and 30.6% in those older than 80 years. A higher mortality was significantly associated with older age and treatment with tocilizumab. Our data showed that although COVID-19 vaccines continue protecting elderly patients against hospitalization and death and might improve the prognosis after hospitalization in patients with breakthrough infections, mortality in this population -especially in those older than 80 years- remains very high.

COVID-19 vaccine effectiveness against hospitalization due to SARS-CoV-2: A test-negative design study based on Severe Acute Respiratory Infection (SARI) sentinel surveillance in Spain

Background

With the emergence of SARS‐CoV‐2, influenza surveillance systems in Spain were transformed into a new syndromic sentinel surveillance system. The Acute Respiratory Infection Surveillance System (SiVIRA in Spanish) is based on a sentinel network for acute respiratory infection (ARI) surveillance in primary care and a network of sentinel hospitals for severe ARI (SARI) surveillance in hospitals.

Methods

Using a test‐negative design and data from SARI admissions notified to SiVIRA between January 1 and October 3, 2021, we estimated COVID‐19 vaccine effectiveness (VE) against hospitalization, by age group, vaccine type, time since vaccination, and SARS‐CoV‐2 variant.

Results

VE was 89% (95% CI: 83–93) against COVID‐19 hospitalization overall in persons aged 20 years and older. VE was higher for mRNA vaccines, and lower for those aged 80 years and older, with a decrease in protection beyond 3 months of completing vaccination, and a further decrease after 5 months. We found no differences between periods with circulation of Alpha or Delta SARS‐CoV‐2 variants, although variant‐specific VE was slightly higher against Alpha.

Conclusions

The SiVIRA sentinel hospital surveillance network in Spain was able to describe clinical and epidemiological characteristics of SARI hospitalizations and provide estimates of COVID‐19 VE in the population under surveillance. Our estimates add to evidence of high effectiveness of mRNA vaccines against severe COVID‐19 and waning of protection with time since vaccination in those aged 80 or older. No substantial differences were observed between SARS‐CoV‐2 variants (Alpha vs. Delta).

Factorial Validity, Reliability, Measurement Invariance and the Graded Response Model for the COVID-19 Anxiety Scale in a Sample of Ecuadorians

The aims of the research are to evaluate the factorial validity, internal consistency, measurement invariance, discrimination, and difficulty of the Covid-19 Anxiety Scale (CAS) applied to a sample of Ecuadorian adults (N = 451). The study is based on an instrumental design with Classical Test Theory (CTT) and Item Response Theory (IRT) technics. The results confirmed the validity of the CAS single-factor structure, with measurement invariance across gender and high internal consistency. Additionally, all CAS items displayed adequate discrimination indexes and proper ordering of the difficulty thresholds. In a conclusion, the CAS is a valid measurement scale for Ecuadorian adults.

Immunogenicity of BNT162b2 COVID-19 vaccine in New Zealand adults

Background

There is very little known about SARS-CoV-2 vaccine immune responses in New Zealand populations at greatest risk for serious COVID-19 disease.

Methods

This prospective cohort study assessed immunogenicity in BNT162b2 mRNA vaccine recipients in New Zealand without previous COVID-19, with enrichment for Māori, Pacific peoples, older adults ≥ 65 years of age, and those with co-morbidities. Serum samples were analysed at baseline and 28 days after second dose for presence of quantitative anti-S IgG by chemiluminescent microparticle immunoassay and for neutralizing capacity against Wuhan, Beta, Delta, and Omicron BA.1 strains using a surrogate viral neutralisation assay.

Results

285 adults with median age of 52 years were included. 55% were female, 30% were Māori, 28% were Pacific peoples, and 26% were ≥ 65 years of age. Obesity, cardiac and pulmonary disease and diabetes were more common than in the general population. All participants received 2 doses of BNT162b2 vaccine. At 28 days after second vaccination, 99.6% seroconverted to the vaccine, and anti-S IgG and neutralising antibody levels were high across gender and ethnic groups. IgG and neutralising responses declined with age. Lower responses were associated with age ≥ 75 and diabetes, but not BMI. The ability to neutralise the Omicron BA.1 variant in vitro was severely diminished but maintained against other variants of concern.

Conclusions

Vaccine antibody responses to BNT162b2 were generally robust and consistent with international data in this COVID-19 naïve cohort with representation of key populations at risk for COVID-19 morbidity. Subsequent data on response to boosters, durability of responses and cellular immune responses should be assessed with attention to elderly adults and diabetics.

Distorted Human Decision-Making as a Critical Aspect of Pandemic Planning and Preparedness

The United States continues to experience lower than expected vaccination rates against COVID-19 due to a variety of barriers such as lack of trust, lack of planning, cultural perspectives and issues, suboptimal communication, and political/economic conflicts of interest. In this paper issues of human behavior and decision-making are highlighted as integral to understanding the generally poor US response to the SARS-CoV-2 pandemic. In particular, the US pandemic response was significantly distorted through a combination of cultural and human behavior issues related to conflicting leadership, cultural individualism, the prevalent idea of the democratization of expertise, and a false epistemological lens for decision-making. Including experts from multiple disciplines reveals how to address the human behavioral side of pandemic planning and operations to increase vaccine coverage rates. Including content experts from psychology and the social sciences allows the explicit recognition and preparation for distorted human behavior in planning for future pandemic response.

Towards the future exploration of mucosal mRNA vaccines against emerging viral diseases; lessons from existing next-generation mucosal vaccine strategies

The mRNA vaccine platform has offered the greatest potential in fighting the COVID-19 pandemic owing to rapid development, effectiveness, and scalability to meet the global demand. There are many other mRNA vaccines currently being developed against different emerging viral diseases. As with the current COVID-19 vaccines, these mRNA-based vaccine candidates are being developed for parenteral administration via injections. However, most of the emerging viruses colonize the mucosal surfaces prior to systemic infection making it very crucial to target mucosal immunity. Although parenterally administered vaccines would induce a robust systemic immunity, they often provoke a weak mucosal immunity which may not be effective in preventing mucosal infection. In contrast, mucosal administration potentially offers the dual benefit of inducing potent mucosal and systemic immunity which would be more effective in offering protection against mucosal viral infection. There are however many challenges posed by the mucosal environment which impede successful mucosal vaccination. The development of an effective delivery system remains a major challenge to the successful exploitation of mucosal mRNA vaccination. Nonetheless, a number of delivery vehicles have been experimentally harnessed with different degrees of success in the mucosal delivery of mRNA vaccines. In this review, we provide a comprehensive overview of mRNA vaccines and summarise their application in the fight against emerging viral diseases with particular emphasis on COVID-19 mRNA platforms. Furthermore, we discuss the prospects and challenges of mucosal administration of mRNA-based vaccines, and we explore the existing experimental studies on mucosal mRNA vaccine delivery.

Comparative effectiveness and durability of COVID-19 vaccination against death and severe disease in an ongoing nationwide mass vaccination campaign

As national coronavirus disease 2019 (COVID-19) mass vaccination campaigns are rolled out, monitoring real-world Vaccine Effectiveness (VE) and its durability is essential. We aimed to estimate COVID-19 VE against severe disease and death in the Greek population, for all vaccines currently in use. Nationwide active surveillance and vaccination registry data during January-December 2021 were used to estimate VE via quasi-Poisson regression, adjusted for age and calendar time. Interaction terms were included to assess VE by age group, against the "delta" severe acute respiratory syndrome coronavirus 2 variant and waning of VE over time. Two doses of BNT162b2, mRNA-1273, or ChAdOx1 nCov-19 vaccines offered very high (>90%) VE against both intubation and death across all age groups, similar against both "delta" and previous variants, with one-dose Ad26.COV2.S slightly lower. VE waned over time but remained >80% at 6 months, and three doses increased VE again to near 100%. Vaccination prevented an estimated 19 691 COVID-19 deaths (95% confidence interval: 18 890-20 788) over the study period. All approved vaccines offer strong and also durable protection against COVID-19 severe disease and death. Every effort should be made to vaccinate the population with at least two doses, to reduce the mortality and morbidity impact of the pandemic.

Hospitalizations from covid-19: a health planning tool

OBJECTIVE

Estimate the future number of hospitalizations from Covid-19 based on the number of diagnosed positive cases.

METHOD

Using the covid-19 Panel data recorded in Spain at the Red Nacional de Vigilancia Epidemiológica, Renave (Epidemiological Surveillance Network), a regression model with multiplicative structure is adjusted to explain and predict the number of hospitalizations from the lagged series of positive cases diagnosed from May 11, 2020 to September 20, 2021. The effect of the time elapsed since the vaccination program starting on the number of hospitalizations is reviewed.

RESULTS

Nine days is the number of lags in the positive cases series with greatest explanatory power on the number of hospitalizations. The variability of the number of hospitalizations explained by the model is high (adjusted R2: 96.6%). Before the vaccination program starting, the expected number of hospitalizations on day t was 20.2% of the positive cases on day t-9 raised to 0.906. After the vaccination program started, this percentage was reduced by 0.3% a day. Using the same model, we find that in the first pandemic wave the number of positive cases was more than six times that reported on official records.

CONCLUSIONS

Starting from the covid-19 cases detected up to a given date, the proposed model allows estimating the number of hospitalizations nine days in advance. Thus, it is a useful tool for forecasting the hospital pressure that health systems shall bear as a consequence of the disease.

Immunogenicity and safety of homologous and heterologous ChAdOx1-S and mRNA-1273 vaccinations in healthy adults in Taiwan

Background

: In Taiwan, the vaccination program started in March 2021, with ChAdOx1-S being the first available WHO-approved COVID-19 vaccine, followed by Moderna vaccine. This study aimed to investigate the immunogenicity and safety of homologous and heterologous prime-boost regimens with ChAdOx1-S and mRNA-1273.

Methods

: From March to November 2021, homologous or heterologous regimens with ChAdOx1-S and mRNA-1273 vaccination (ChAdOx1-S/ChAdOx1-S, mRNA-1273/mRNA-1273, ChAdOx1-S/mRNA-1273) were given to 945 healthy participants. Serum samples were collected at designated time points. The anti-RBD/S1 antibody titers and neutralizing ability were measured by three different immunoassays: Elecsys® Anti-SARS-CoV-2 S (Roche Diagnostics, Mannheim, Germany), AdviseDx SARS-CoV-2 IgG II (Abbott Diagnostics Division, Sligo, Ireland), and cPass™ SARS-CoV-2 Neutralization Antibody Detection Kit (GenScript, New Jersey, USA).

Results

: We found that heterologous vaccination with ChAdOx1-S/mRNA-1273 had an acceptable safety profile and induced higher total anti-RBD/S1 antibody production (p < 0.0001), yet lower anti-RBD/S1 IgG titer (p < 0.0001) and neutralizing ability (p = 0.0101) than mRNA-1273/mRNA-1273 group. Both regimens showed higher antibody titers and superior neutralizing abilities than ChAdOx1-S/ChAdOx1-S. An age-dependent antibody response to ChAdOx1-S/mRNA-1273 was shown after both the priming and the booster doses. Younger age was associated with higher antibody production and neutralizing ability.

Conclusions

: Heterologous ChAdOx1-S/mRNA-1273 vaccination regimen is generally safe and induces a robust humoral immune response that is non-inferior to that of mRNA-1273/mRNA-1273.