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Reported effectiveness of COVID-19 monovalent booster vaccines and hybrid immunity against mild and severe Omicron disease in adults: A systematic review and meta-regression analysis

2024; Elsevier BV; Volume: 17; Linguagem: Inglês

10.1016/j.jvacx.2024.100451

2590-1362

Joshua Nealon, Yonatan M. Mefsin, Martina McMenamin, Kylie E. C. Ainslie, Benjamin J. Cowling,

COVID-19 Clinical Research Studies

Waning of COVID-19 vaccine efficacy/effectiveness (VE) has been observed across settings and epidemiological contexts. We conducted a systematic review of COVID-19 VE studies and performed a meta-regression analysis to improve understanding of determinants of waning. Systematic review of PubMed, medRxiv and the WHO-International Vaccine Access Center database summarizing VE studies on 31 December 2022. Studies were those presenting primary adult VE data from hybrid immunity or third/fourth mRNA COVID-19 monovalent vaccine doses [due to limited data with other vaccines] against Omicron, compared with unvaccinated individuals or individuals eligible for corresponding booster doses but who did not receive them. We used meta-regression models, adjusting for confounders, with weeks since vaccination as a restricted cubic spline, to estimate VE over time since vaccination. We identified 55 eligible studies reporting 269 VE estimates. Most estimates (180/269; 67%) described effectiveness of third dose vaccination; with 48 (18%) and 41 (15%) describing hybrid immunity and fourth dose effectiveness, respectively, mostly (200; 74%) derived from test-negative design studies. Most estimates (176/269; 65%) reported VE compared with unvaccinated comparison groups. Estimated VE against mild outcomes declined following third dose vaccination from 62% (95% CI: 58% – 66%) after 4 weeks to 48% (41% – 55%) after 20 weeks. Fourth dose VE against mild COVID-19 declined from 48% (41% – 56%) after 4 weeks to 47% (19% – 65%) after 20 weeks. VE for severe outcomes was higher and declined in the three-dose group from 90% (87% – 92%) after 4 weeks to 70% (65 – 74%) after 20 weeks. Time-since vaccination is an important determinant of booster dose VE, a finding which may support seasonal COVID-19 booster doses. Integration of VE and immunological parameters – and longer-term data including from other vaccine types – are needed to better-understand determinants of clinical protection.