The impact of vaccination on preventing long COVID in the Omicron era: a systematic review and meta-analysis

Abstract

Millions worldwide are living with long COVID. Since therapeutic research is ongoing, long COVID prevention is a pragmatic public health strategy. While prior analyses have shown the benefit of primary vaccination, the effect of booster vaccination on preventing long COVID caused by an Omicron infection has not been fully investigated. This systematic review identified 31 observational studies, among which 11 were deemed suitable for pairwise meta-analyses. Herein, the pooled risk of long COVID was 22-29% (P<0.0001 and P<0.0001, respectively) lower for vaccinated (any vaccination) populations versus unvaccinated (10 studies); 19% (P<0.0001) lower for primary course vaccination versus no vaccination (3 studies); 26% (P<0.0001) lower for booster vaccination versus no vaccination (4 studies) and 23% (P=0.0044) lower for booster vaccination versus primary course vaccination (3 studies). These findings indicate that booster vaccination can provide additional protection against long COVID; thereby, highlighting the importance of seasonal vaccination against new SARS-CoV-2 variants.