The relative effectiveness of three and four doses of COVID-19 vaccine in Victoria, Australia: A data linkage study

BACKGROUND

The Coronavirus Disease 2019 (COVID-19) pandemic led to extensive vaccination campaigns worldwide, including in Australia. Immunity waning and the emergence of new viral variants pose challenges to the effectiveness of vaccines. Our study aimed to assess the relative effectiveness (rVE) of 3 and 4 compared with 2 doses of COVID-19 vaccine. The study focuses on the Victorian population, a majority of whom had no prior exposure to the virus before vaccination.

METHODS

We used routinely collected data for the state of Victoria, Australia, to assess rVE during an Omicron-dominant period, 1 June 2022 to 1 March 2023. Immunisation, notifications, hospitalisations and mortality data for residents aged 65 years and older were linked for analysis. Cox proportional hazard regression was used to estimate the rVE against COVID-19 hospitalisation or death, accounting for key confounders with vaccination as a time-varying covariate.

RESULTS

In 1,070,113 people 65 years or older who had received their second dose, a third and fourth dose of a COVID-19 vaccine significantly reduced the hazard of hospitalisation or death compared to two doses. rVE was highest within two weeks from administration at 40 % (95 % CI: 0 % to 64 %) and 66 % (95 % CI: 60 % to 71 %) for a third and fourth dose, respectively. Additional protection conferred by third and fourth doses waned over time from administration.

CONCLUSIONS

Our findings underscore the need for additional vaccine doses and updated vaccine strategies. These findings have implications for public health advice and COVID-19 vaccine strategies. Further research and monitoring of vaccine effectiveness in real-world settings are warranted to inform ongoing pandemic response efforts.

Risk of severe COVID-19 in unvaccinated patients during the period from wild-type to Omicron variant: real-world evidence from Japan

BACKGROUND

Many studies have reported that the Omicron variant is less pathogenic than the Delta variant and the wild-type. Epidemiological evidence regarding the risk of severe COVID-19 from the wild-type to the Omicron variant has been lacking.

METHODS

Study participants were COVID-19 patients aged 18 and older without previous COVID-19 infection who were notified to the Nara Prefecture Chuwa Public Health Center from January 2020 to March 2023, during the periods from the wild-type to the Omicron variant. The outcome variable was severe COVID-19 (i.e., ICU admission or COVID-19-related death). The explanatory variable was SARS-CoV-2 variant type or the number of COVID-19 vaccinations. Covariates included gender, age, risk factors for aggravation, and the number of general hospital beds per population. The generalized estimating equations of negative binomial regression models were used to estimate the adjusted incidence proportion (AIP) with 95% confidence interval (CI) for severe COVID-19.

RESULTS

Among 77,044 patients included in the analysis, 14,556 (18.9%) were unvaccinated and 520 (0.7%) developed severe COVID-19. Among unvaccinated patients, the risk of severe COVID-19 increased in the Alpha/Delta variants and decreased in the Omicron variant compared to the wild-type (AIP [95% CI] was 1.55 [1.06-2.27] in Alpha/Delta and 0.25 [0.15-0.40] in Omicron), but differed by age. Especially in patients aged ≥80, there was no significant difference in the risk of severe COVID-19 between the wild-type and the Omicron variant (AIP [95% CI] = 0.59 [0.27-1.29]). Regarding the preventive effect of vaccines, among all study participants, the number of vaccinations was significantly associated with the prevention of severe COVID-19, regardless of variant type. After stratified analyses by age, patients aged ≥80 remained a significant association for all variant types. On the other hand, the number of vaccinations had no association in Omicron BA.5 of patients aged 18-64.

CONCLUSIONS

Patients aged ≥80 had less reduction in risk of severe COVID-19 during the Omicron variant period, and a greater preventive effect of vaccines against severe COVID-19, compared to younger people. Our findings suggest that booster vaccination is effective and necessary for older people, especially aged ≥80.

Cold Agglutinin Disease and COVID-19: A Scoping Review of Treatments and Outcomes

Background

Reports suggest that patients with both acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and cold agglutinin disease (CAD) may experience poorer survival when treated with rituximab. We conducted a scoping review to evaluate severe outcomes, including intensive care unit (ICU) admission and mortality, in coronavirus disease 2019 (COVID-19) patients with CAD on various treatments, including rituximab.

Methods

This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR). Four literature databases were searched on December 19, 2023, for studies reporting lab-confirmed SARS-CoV-2 and CAD, excluding rheumatological conditions.

Results

Of the 741 screened articles, 19 were included. Studies, predominantly case reports (17/19) or case series (2/19), were mainly from the USA (8/19) and India (3/19), with others across Europe and Asia. Among 23 patients (61% female, median age 61 years), 21/23 had a new CAD diagnosis; only two had pre-existing CAD. Overall, 74% recovered, 21% died, and outcomes for one were unreported. Nine (39%) were ICU-admitted. Of rituximab-treated patients (n = 4), 25% were ICU-admitted, none died. Non-rituximab treatments (n = 19) saw 42% ICU admissions and 26% mortality.

Conclusions

This review found no increased risk of severe outcomes in CAD and COVID-19 patients treated with rituximab.

COVID-19 outbreaks in residential care homes in Hong Kong and effectiveness of vaccine against severe outcomes

Background

COVID-19 outbreaks in residential care homes for the elderly (RCHEs) and for persons with disability (RCHDs) have caused significant morbidity and mortality during 5th epidemic in Hong Kong. This article reviewed COVID-19 outbreaks situation and estimated the effectiveness of receiving at least two-dose of COVID-19 vaccine in preventing severe outcomes.

Methods

To estimate attack rates and vaccination coverage, documentation on COVID-19 infection and their vaccination records of residential care homes (RCH) residents reported between December 31, 2021 and May 31, 2022 were reviewed, and infected cases were follow-up for 4 weeks for severe outcomes or death. Correlation between vaccination coverage against attack rate by types of homes was examined. Infected RCH residents with available information were included in the analysis of vaccine effectiveness against severe outcomes and death.

Results

COVID-19 vaccination coverage was low in RCHDs (median 0.46, IQR: 0.24-0.76) and very low in RCHEs (median 0.08, IQR: 0.00-0.19). Higher attack rates were recorded among RCHE residents (median 0.84, IQR: 0.64-0.93) and higher case fatality rate (CFR: 28.1%) than in RCHDs (median 0.58, IQR: 0.31-0.84; CFR: 3.9%). The attack rate decreased when vaccination coverage increased for both RCHEs (ρ = -0.131, p < 0.001) and RCHDs (ρ = -0.333, p < 0.001). Comparing with infected residents who were unvaccinated/vaccinated with one-dose, receiving at least two-dose was estimated to be effective in reducing severe outcomes in 31% and 36% of infected RCHE and RCHD residents respectively; with greater reduction in mortality among RCHD than RCHE residents (54% and 38%, respectively). Vaccine effectiveness of two-dose of BNT162b2 against severe outcomes and death are higher than that of CoronaVac.

Conclusions

Increasing COVID-19 vaccination could have significant impact on reducing the risk of COVID-19 outbreaks in RCHs. At least two-dose of COVID-19 vaccine is still effective in reducing severe outcomes and death among infected residents in RCHs during Omicron epidemic.

Risk of Covid-19 Severe Outcomes and Mortality in Migrants and Ethnic Minorities Compared to the General Population in the European WHO Region: a Systematic Review

The Covid-19 pandemic has had a major impact on migrants and ethnic minorities (MEMs). Socio-economic factors and legal, administrative and language barriers are among the reasons for this increased susceptibility. The aim of the study is to investigate the impact of Covid-19 on MEMs compared to the general population in terms of serious outcomes. We conducted a systematic review collecting studies on the impact of Covid-19 on MEMs compared to the general population in the WHO European Region regarding hospitalisation, intensive care unit (ICU) admission and mortality, published between 01/01/2020 and 19/03/2021. Nine researchers were involved in selection, study quality assessment and data extraction. Of the 82 studies included, 15 of the 16 regarding hospitalisation for Covid-19 reported an increased risk for MEMs compared to the white and/or native population and 22 out of the 28 studies focusing on the ICU admission rates found an increased risk for MEMs. Among the 65 studies on mortality, 43 report a higher risk for MEMs. An increased risk of adverse outcomes was reported for MEMs. Social determinants of health are among the main factors involved in the genesis of health inequalities: a disadvantaged socio-economic status, a framework of structural racism and asymmetric access to healthcare are linked to increased susceptibility to the consequences of Covid-19. These findings underline the need for policymakers to consider the socio-economic barriers when designing prevention plans.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12134-023-01007-x.

Association between vaccination status and severe health consequences among community-dwelling COVID-19 patients during Omicron BA.1/BA.2 and BA.5-predominant periods in Japan

BACKGROUND

Many previous studies have reported that COVID-19 vaccine effectiveness decreased over time and declined with newly emerging variants. However, there are few such studies in Japan. Using data from a community-based retrospective study, we aimed to assess the association between vaccination status and severe COVID-19 outcomes caused by the Omicron variant, considering the length of time since the last vaccination dose.

METHODS

We included all persons aged ≥12 diagnosed with COVID-19 by a doctor and notified to the Chuwa Public Health Center of Nara Prefectural Government during the Omicron BA.1/BA.2 and BA.5-predominant periods in Japan (January 1 to September 25, 2022). The outcome variable was severe health consequences (SHC) (i.e., COVID-19-related hospitalization or death). The explanatory variable was vaccination status of the individuals (i.e., the number of vaccinations and length of time since last dose). Covariates included gender, age, risk factors for aggravation, and the number of hospital beds per population. Using the generalized estimating equations of the multivariable Poisson regression models, we estimated the cumulative incidence ratio (CIR) and 95% confidence interval (CI) for SHC, with stratified analyses by period (BA.1/BA.2 or BA.5) and age (65 and older or 12-64 years).

RESULTS

Of the 69,827 participants, 2,224 (3.2%) had SHC, 12,154 (17.4%) were unvaccinated, and 29,032 (41.6%) received ≥3 vaccine doses. Regardless of period or age, there was a significant dose-response relationship in which adjusted CIR for SHC decreased with an increased number of vaccinations and a longer time since the last vaccination. On the one hand, in the BA.5 period, those with ≥175 days after the third dose had no significant difference in people aged 65 and older (CIR 0.77; 95% CI, 0.53-1.12), but significantly lower CIR for SHC in people aged 12-64 (CIR 0.47; 95% CI, 0.26-0.84), compared with those with ≥14 days after the second dose.

CONCLUSION

A higher number of vaccinations were associated with lower risk of SHC against both BA.1/BA.2 and BA.5 sublineages. Our findings suggest that increasing the number of doses of COVID-19 vaccine can prevent severe COVID-19 outcomes, and that a biannual vaccination is recommended for older people.

Optimising the impact of COVID-19 vaccination on mortality and hospitalisations using an individual additive risk measuring approach based on a risk adjustment scheme

In this population-based cohort study, billing data from German statutory health insurance (BARMER, 10% of population) are used to develop a prioritisation model for COVID-19 vaccinations based on cumulative underlying conditions. Using a morbidity-based classification system, prevalence and risks for COVID-19-related hospitalisations, ventilations and deaths are estimated. Trisomies, behavioural and developmental disorders (relative risk: 2.09), dementia and organic psychoorganic syndromes (POS) (2.23) and (metastasised) malignant neoplasms (1.99) were identified as the most important conditions for escalations of COVID-19 infection. Moreover, optimal vaccination priority schedules for participants are established on the basis of individual cumulative escalation risk and are compared to the prioritisation scheme chosen by the German Government. We estimate how many people would have already received a vaccination prior to escalation. Vaccination schedules based on individual cumulative risk are shown to be 85% faster than random schedules in preventing deaths, and as much as 57% faster than the German approach, which was based primarily on age and specific diseases. In terms of hospitalisation avoidance, the individual cumulative risk approach was 51% and 28% faster. On this basis, it is concluded that using individual cumulative risk-based vaccination schedules, healthcare systems can be relieved and escalations more optimally avoided.

Cardiovascular comorbidities as predictors for severe COVID-19 infection or death

Aims 

Pre-existing cardiovascular diseases (CVDs) have been proposed to identify patients at higher risk of adverse coronavirus disease 2019 (COVID-19) outcomes, but existing evidence is conflicting. Thus, it is unclear whether pre-existing CVDs are independently important predictors for severe COVID-19.

Methods and results 

In a nationwide Danish cohort of hospital-screened COVID-19 patients aged ≥40, we investigated if pre-existing CVDs predict the 30-day risk of (i) composite outcome of severe COVID-19 and (ii) all-cause mortality. We estimated 30-day risks using a Cox regression model including age, sex, each CVD comorbidity, chronic obstructive pulmonary disease-asthma, diabetes, and chronic kidney disease. To illustrate CVD comorbidities’ importance, we evaluated the predicted risks of death and severe infection, for each sex, along ages 40–85. In total, 4090 COVID-19 hospital-screened patients were observed as of 26 August 2020; 22.1% had ≥1 CVD, 23.7% had severe infection within 30 days and 12.6% died. Predicted risks of both outcomes at age 75 among men with single CVD comorbidities did not differ in clinically meaningful amounts compared with men with no comorbidities risks for the composite outcome of severe infection; women with heart failure (28.2%; 95% CI 21.1–37.0%) or atrial fibrillation (30.0%; 95% CI: 24.2–36.9%) showed modest increases compared with women with no comorbidities (24.0%; 95% CI: 21.4–26.9%).

Conclusions 

The results showing only modest effects of CVDs on increased risks of poor COVID-19 outcomes are important in allowing public health authorities and clinicians to provide more tailored guidance to cardiovascular patients, who have heretofore been grouped together as high risk due to their disease status.

Epidemiology of severe buprenorphine exposures reported to the U.S. Poison Centers

OBJECTIVE

This study aims to evaluate the trends and risk factors of severe buprenorphine outcomes (SBO) reported to the U.S. Poison Centers (PCs).

METHODS

We queried the National Poison Data System for exposures to buprenorphine from 2011 to 2016. SBO cases were defined as exposures that resulted in either a death or major clinical outcomes. Trends were tested using Poisson regression. Characteristics of the exposures were descriptively assessed. Logistic regression was used to evaluate the risk factors of SBO.

RESULTS

SBO cases (967) reported to the PCs increased by 66.6% during this period (114-190, p < 0.001). While adults between 20 and 39 years were more frequent in the SBO group (50.4%) compared to the non-SBO group (38.7%), cases under 6 years (29.6% vs 13.8%) were more common among the non-SBO group. Intentional abuse (20.1% vs 24.9%) and suspected suicides (13.7% vs 37.5%) were significantly higher among the SBO group. Multisubstance exposures were more frequent among the SBO cases (36.4% vs 71.4%). SBO risk increased with age, with cases above 60 years (AOR: 1.66, 95% CI: 1.14-2.42) demonstrating significantly increased odds. Suspected suicide (AOR: 1.87, 95% CI: 1.53-2.28) and abuse (AOR: 1.40, 95% CI: 1.13-1.73) cases were more likely to result in a SBO. Multisubstance exposures significantly increased the risk of a SBO.

CONCLUSIONS

This study reflected an increase in the cases of SBO paralleling the rise in the buprenorphine prescriptions. Age, reasons for exposure and multi-substance exposures significantly increased the risk of SBO.

TURN Score Predicts 24-Hour Cerebral Edema After IV Thrombolysis

BACKGROUND AND PURPOSE

Cerebral edema is associated with poor outcome after IV thrombolysis. We recently described the TURN score (Thrombolysis risk Using mRS and NIHSS), a predictor of severe outcome after IV thrombolysis. Our purpose was to evaluate its ability to predict 24-h cerebral edema.

METHODS

We retrospectively analyzed data from 303 patients who received IV rt-PA during the NINDS rt-PA trial. Measures of brain swelling included edema, mass effect and midline shift assessed at baseline, at 24 h and new onset at 24 h. Outcome was assessed using intracerebral hemorrhage (ICH), symptomatic intracerebral hemorrhage (sICH), 90-day severe outcome, and 90-day mortality. Statistical associations were assessed by logistic regression reporting odds ratios (OR) and by areas under the receiver operating characteristic curves (AUROC).

RESULTS

Baseline brain swelling did not predict poor outcome; however, 24-h brain swelling predicted ICH (OR 5.69, P < 0.001), sICH (OR 9.50, P = 0.01), 90-day severe outcome (OR 7.10, P < 0.001), and 90-day mortality (OR 5.65, P = 0.01). Similar results were seen for new brain swelling at 24 h. TURN predicted 24-hour brain swelling (OR 2.5, P < 0.001; AUROC 0.69, 95 % CI 0.63-0.75) and new brain swelling at 24 h (OR 2.1, P < 0.001; AUROC 0.67, 95 % CI 0.61-0.73).

CONCLUSIONS

Cerebral edema at 24 h is associated with poor outcome and 90-day mortality. TURN predicts ischemic stroke patients who will develop 24-h cerebral edema after IV thrombolysis.

Relative incidence and individual-level severity of seasonal influenza A H3N2 compared with 2009 pandemic H1N1

Background

Two subtypes of influenza A currently circulate in humans: seasonal H3N2 (sH3N2, emerged in 1968) and pandemic H1N1 (pH1N1, emerged in 2009). While the epidemiological characteristics of the initial wave of pH1N1 have been studied in detail, less is known about its infection dynamics during subsequent waves or its severity relative to sH3N2. Even prior to 2009, few data was available to estimate the risk of severe outcomes following infection with one circulating influenza strain relative to another.

Methods

We analyzed antibodies in quadruples of sera from individuals in Hong Kong collected between July 2009 and December 2011, a period that included three distinct influenza virus epidemics. We estimated infection incidence using these assay data and then estimated rates of severe outcomes per infection using population-wide clinical data.

Results

Cumulative incidence of infection was high among children in the first epidemic of pH1N1. There was a change towards the older age group in the age distribution of infections for pH1N1 from the first to the second epidemic, with the age distribution of the second epidemic of pH1N1 more similar to that of sH3N2. We found no serological evidence that individuals were infected in both waves of pH1N1. The risks of excess mortality conditional on infection were higher for sH3N2 than for pH1N1, with age-standardized risk ratios of 2.6 [95% CI: 1.8, 3.7] for all causes and 1.5 [95% CI: 1.0, 2.1] for respiratory causes throughout the study period.

Conclusions

Overall increase in clinical incidence of pH1N1 and higher rates of severity in older adults in post pandemic waves were in line with an age-shift in infection towards the older age groups. The absence of repeated infection is good evidence that waning immunity did not cause the second wave. Despite circulating in humans since 1968, sH3N2 is substantially more severe per infection than the pH1N1 strain. Infection-based estimates of individual-level severity have a role in assessing emerging strains; updating seasonal vaccine components; and optimizing of vaccination programs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2432-7) contains supplementary material, which is available to authorized users.

Risk rtPA: An iOS mobile application based on TURN for predicting 90-day outcome after IV thrombolysis

OBJECTIVE

We recently developed Thrombolysis risk Using mRS and NIHSS (TURN), a simple score using only prestroke mRS scores and admission NIHSS scores to predict 90-day outcome after IV thrombolysis in ischemic stroke patients. Our purpose was to develop and test a mobile application for utilization of TURN at the bedside.

METHODS

We developed Risk rtPA, an iOS mobile application based on TURN for prediction of 90-day excellent and severe outcome after IV thrombolysis. Excellent outcome was defined as 90-day mRS≤1. Severe outcome was defined as 90-day mRS≥5. Predictors for excellent and severe outcome were calculated using the inverse logit of -TURN and TURN respectively. We retrospectively validated our mobile application using data from 303 patients who received IV rt-PA during the NINDS rt-PA trial. Sensitivity and specificity analyses were performed using receiver operating characteristic (ROC) curves.

RESULTS

Prediction of excellent and severe outcome using Risk rtPA followed an S-shaped curve as expected. We confirmed this finding using data from the NINDS trial. Cutoffs selected after ROC analysis predicted severe outcome with sensitivity of 94.4% and specificity of 52.2%, and excellent outcome with specificity of 83.9% and sensitivity of 61.2%.

CONCLUSION

The Risk rtPA mobile application predicted 90-day excellent and severe outcome in most clinically relevant cases. This mobile application brings the TURN score to the bedside for prediction of 90-day outcome in ischemic stroke patients being evaluated for IV thrombolysis.