Background
Sex and gender are believed to influence vaccine response. Yet, the relationship between sex and gender and COVID-19 vaccine efficacy is poorly understood and remains under-investigated.
Methods
We conducted a systematic review to determine whether and to what extent post-approval COVID-19 vaccine effectiveness (VE) studies report sex-disaggregated VE data.
We searched four publication and pre-publication databases and additional grey literature sources for relevant published/preprint studies released between 1 January 2020 and 1 October 2021 (i.e., pre-Omicron era). We included observational studies providing VE estimates for one or more licensed/approved COVID-19 vaccines and including both males and females. Two reviewers independently assessed study eligibility, extracted data, and assessed risk-of-bias through a modified version of Cochrane’s ROBINS-I tool. A qualitative data synthesis was performed.
Results
Here we show that, among 240 eligible publications, 68 (28.3%) do not report the sex distribution among participants. Only 21/240 (8.8%) studies provide sex-disaggregated VE estimates, and high between-study heterogeneity regarding design, target population, outcomes, and vaccine type/timing prevent the assessment of sex in determining COVID-19 VE across studies.
Conclusions
Our findings indicate that few COVID-19 vaccine research publications account for sex. Improved adherence to recommended reporting guidelines will ensure that the evidence generated can be used to better understand the relationship between sex and gender and VE.
Objective
Lassa fever (LF) is caused by a viral pathogen with pandemic potential. LF vaccines have the potential to prevent significant disease in individuals at risk of infection, but no such vaccine has been licensed or authorised for use thus far. We conducted a scoping review to identify and compare registered phase 1, 2 or 3 clinical trials of LF vaccine candidates, and appraise the current trajectory of LF vaccine development.
Method
We systematically searched 24 trial registries, PubMed, relevant conference abstracts and additional grey literature sources up to 27 October 2022. After extracting key details about each vaccine candidate and each eligible trial, we qualitatively synthesised the evidence.
Results
We found that four LF vaccine candidates (INO‐4500, MV‐LASV, rVSV∆G‐LASV‐GPC, and EBS‐LASV) have entered the clinical stage of assessment. Five phase 1 trials (all focused on healthy adults) and one phase 2 trial (involving a broader age group from 18 months to 70 years) evaluating one of these vaccines have been registered to date. Here, we describe the characteristics of each vaccine candidate and trial and compare them to WHO's target product profile for Lassa vaccines.
Conclusion
Though LF vaccine development is still in early stages, current progress towards a safe and effective vaccine is encouraging.
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