Objective To summarise the available evidence on the risk of myocarditis and/or pericarditis following mRNA COVID-19 vaccination, compared with the risk among unvaccinated individuals in the absence of COVID-19 infection. Design Systematic review and meta-analysis. Data sources Electronic databases (Medline, Embase, Web of Science and WHO Global Literature on Coronavirus Disease), preprint repositories (medRxiv and bioRxiv), reference lists and grey literature were searched from 1 December 2020 until 31 October 2022. Study selection Epidemiological studies of individuals of any age who received at least one dose of an mRNA COVID-19 vaccine, reported a risk of myo/pericarditis and compared the risk of myo/pericarditis to individuals who did not receive any dose of an mRNA COVID-19 vaccine. Data extraction and synthesis Two reviewers independently conducted screening and data extraction. The rate of myo/pericarditis among vaccinated and unvaccinated groups was recorded, and the rate ratios were calculated. Additionally, the total number of individuals, case ascertainment criteria, percentage of males and history of SARS-CoV-2 infection were extracted for each study. Meta-analysis was done using a random-effects model. Results Seven studies met the inclusion criteria, of which six were included in the quantitative synthesis. Our meta-analysis indicates that within 30-day follow-up period, vaccinated individuals were twice as likely to develop myo/pericarditis in the absence of SARS-CoV-2 infection compared to unvaccinated individuals, with a rate ratio of 2.05 (95% CI 1.49–2.82). Conclusion Although the absolute number of observed myo/pericarditis cases remains quite low, a higher risk was detected in those who received mRNA COVID-19 vaccinations compared with unvaccinated individuals in the absence of SARS-CoV-2 infection. Given the effectiveness of mRNA COVID-19 vaccines in preventing severe illnesses, hospitalisations and deaths, future research should focus on accurately determining the rates of myo/pericarditis linked to mRNA COVID-19 vaccines, understanding the biological mechanisms behind these rare cardiac events and identifying those most at risk.

Vaccines effectively protect against COVID-19, but vaccine hesitancy and refusal hinder vaccination rates. This systematic review aimed to (1) review and describe current interventions for addressing COVID-19 vaccine hesitancy/refusal and (2) assess whether these interventions are effective for increasing vaccine uptake. The protocol was registered prospectively on PROSPERO and comprehensive search included Medline, Embase, CINAHL, PsycInfo, and Web of Science databases. Only studies that evaluated the effectiveness of non-financial interventions to address COVID-19 vaccine hesitancy were included, while those focusing intentions or financial incentive were excluded. Risk of bias for all included studies was evaluated using Cochrane risk of bias tools. In total, six articles were included in the review (total participants n = 200,720). A narrative synthesis was performed due to the absence of common quantitative metrics. Except for one randomized controlled trial, all studies reported that interventions were effective, increasing COVID-19 vaccination rates. However, non-randomized studies were subject to confounding biases. Evidence on the effectiveness of COVID-19 vaccine hesitancy interventions remains limited and further evidence is needed for the development of clear guidance on effective interventions to increase vaccine uptake.

There have been reports of cases of myocarditis and pericarditis as rare complications following mRNA COVID-19 vaccinations among young adults. While most reported cases are mild, this potential vaccine safety signal should be closely monitored. Using data from the CDC and the Vaccine Adverse Event Reporting System (VAERS), we calculated the combined reporting rate of myocarditis and pericarditis stratified by age group, sex, vaccine dose, and manufacturer, and compared these rates to the crude background incidence rates. Compared to the general population prior to the administration of the first COVID-19 vaccines in December 2020, we identified a higher-than-expected reporting rate of myocarditis and pericarditis following mRNA vaccination; the risk was higher after a second vaccine dose, higher in males than in females, and decreased with age. The highest risk was seen in males 12–17 years of age with approximately 6 cases per 100,000 second doses. Our findings suggest an increased risk of myocarditis and pericarditis in young males following a second dose of an mRNA COVID-19 vaccine. Since these findings are based on safety signals derived from passive surveillance data, confirmatory epidemiological studies should be undertaken.

Objectives To describe the post-marketing safety profile of respiratory syncytial virus prefusion F (RSVpreF) vaccine among pregnant individuals. Design This study analysed adverse event (AE) reports submitted to the U.S. Food and Drug Administration’s Vaccine Adverse Event Reporting System (VAERS) database following RSVpreF immunisation from 1 September 2023 to 23 February 2024. Setting VAERS, as a national spontaneous vaccine safety surveillance system, provides insights into the safety profile of the RSVpreF vaccine in a real-world setting. Participants Surveillance data included all AE reports submitted to VAERS in pregnant individuals following vaccination. Exposure Receipt of RSVpreF vaccine among pregnant individuals in the USA. Primary and secondary outcome measures Descriptive statistics were used to assess all AE reports with RSVpreF, including frequency, gestational age at vaccination, time to AE onset, reported outcomes and proportion of serious reports. Data mining techniques were employed to identify disproportionate reporting of RSVpreF-event pairs. Reports of preterm births were clinically reviewed. Results VAERS received 77 reports pertaining to RSVpreF vaccination in pregnant individuals, with 42 (54.55%) classified as serious. The most frequently reported non-pregnancy-specific AEs were headache, injection site erythema and injection site pain. For pregnancy-specific AEs, preterm birth was the most frequently reported (12.8%), followed by AE terms such as preterm premature rupture of membranes and caesarean section (each at 3.3%), and cervical dilatation, haemorrhage during pregnancy and uterine contractions during pregnancy (each at 1.4%). Our disproportionality analysis indicated signals for various AEs, particularly preterm birth, indicating that reports of preterm birth in conjunction with RSVpreF vaccination were observed more frequently than statistically expected. Most of the reported preterm births were moderate to late, occurring between 32 and less than 37 weeks of gestation. The median time from immunisation to the onset of preterm birth was 3 days, with two-thirds of cases reported within a week of vaccination. Conclusions The AEs reported to VAERS among pregnant individuals vaccinated with RSVpreF largely aligned with the safety profile observed in prelicensure studies; however, this analysis also highlights the previously observed safety signal for preterm birth. Active surveillance studies focusing on maternal and perinatal outcomes are needed to further evaluate this signal and guide future clinical recommendations.

Objectives: To evaluate reports of diabetic ketoacidosis (DKA) associated with antipsychotic drug (APD) use submitted to the U.S. Food and Drug Administration’s Adverse Event Reporting System (FAERS). Methods: A retrospective pharmacovigilance analysis was conducted using FAERS data from January 2000 to December 2022. DKA cases were identified using the MedDRA preferred term “diabetic ketoacidosis” in reports listing antipsychotic drugs as suspect medications. Disproportionality analyses, including the proportional reporting ratio (PRR) and empirical Bayes geometric mean (EBGM), were used to assess reporting patterns. Multiple analyses were performed, including those restricted to primary suspect listed drugs only, expanded to incorporate secondary suspect drugs, and sensitivity analyses excluding reports submitted by legal professionals. Results: Among 19,961 DKA reports in FAERS, 2489 (12.5%) listed atypical antipsychotics as the primary suspect drug, whereas reports involving typical APDs were rare. The majority of reports were submitted by healthcare professionals (74.1%), and nearly half originated from the United States (45.4%). Hospitalization was a frequent outcome, reported in 74.3% of cases. Quetiapine and olanzapine were the most frequently reported atypical APDs, with disproportionality analyses demonstrating strong safety signals when compared to all other drugs in FAERS: olanzapine PRR 13.2 (95% CI: 12.4–14.2) and quetiapine PRR 11.8 (95% CI: 11.1–12.5). The findings remained consistent across multiple sensitivity analyses, including incorporating secondary suspect drugs, when the comparator group was restricted to only psychotropic drugs, and excluding reports submitted by lawyers. Conclusions: This pharmacovigilance analysis highlights a potential safety signal for DKA with atypical antipsychotic drugs, notably quetiapine and olanzapine. While these findings do not establish causality, they underscore the need for further investigation using clinical and epidemiological data.

Objectives To describe the post-marketing safety of RSVPreF among pregnant individuals. Design This case series study analyzed adverse event (AE) reports submitted to the U.S. Food and Drug Administration’s Vaccine Adverse Event Reporting System (VAERS) database following RSVPreF immunization from September 1, 2023, to February 23, 2024. Setting VAERS, as a national spontaneous vaccine safety surveillance system, provides insights into the safety profile of the RSVPreF vaccine in a real-world setting. Participants Surveillance data included all AE reports submitted to VAERS for pregnant individuals following vaccination. Exposure Receipt of RSVPreF vaccine among pregnant individuals in the U.S. Primary and secondary outcome measures Descriptive statistics assessed all AE reports with RSVPreF, including frequency, gestational age at vaccination, time to AE onset, and serious report proportions. The Bayesian Confidence Propagation Neural Network (BCPNN) was utilized, estimating the information component (IC) to identify disproportionate reporting of RSVPreF–event pairs. Results VAERS received 77 reports pertained to RSVPreF vaccination in pregnant individuals, with 42 (54.55%) classified as serious. The most reported non-pregnancy-specific AEs were headache, injection site erythema, and injection site pain. Preterm birth was the most frequently reported pregnancy-specific AE, followed by preterm premature rupture of membranes, cesarean section, cervical dilatation, and hemorrhage during pregnancy. The median time from immunization to reported preterm birth was 3 days, with two-thirds of cases within a week. Disproportionality analysis indicated a significant signal for various AEs, particularly highlighting preterm birth with an IC of 2.18 (95%CI, 1.54-2.63), suggesting that reports of preterm birth associated with RSVPreF vaccination occurred more frequently than statistically expected. Conclusions While reported AEs were generally consistent with the safety profile observed in prelicensure studies, this study highlights ongoing concern about preterm birth among pregnant individuals following RSVPreF vaccination. Comprehensive longitudinal follow-up, including prospective pregnancy registries and infant follow-up studies is urgently required.