Background A rapidly growing body was observed of literature evaluating the vaccine
effectiveness (VE) against Omicron in test-negative design studies. Methods We …

Importance Estimates of the rate of waning of vaccine effectiveness (VE) against COVID-19
are key to assess population levels of protection and future needs for booster doses to face …

Abstract The coronavirus disease 2019 (COVID‐19) pandemic can hardly end with the
emergence of different variants over time. In the past 2 years, several variants of severe …

Background Synthesising evidence on the long-term vaccine effectiveness of COVID-19
vaccines (BNT162b2 [Pfizer–BioNTech], mRNA-1273 [Moderna], ChAdOx1 nCoV-19 …

Background The two inactivated SARS-CoV-2 vaccines, CoronaVac and BBIBP-CorV, have
been widely used to control the COVID-19 pandemic. The influence of multiple factors on …

The Omicron (B. 1.1. 529) variant of the severe acute respiratory syndrome Coronavirus 2
(SARS-CoV-2) had an increased rate of spreading among the general population. Although …

The repetitive applications of vaccine boosters have been brought up in face of continuous
emergence of SARS-CoV-2 variants with neutralization escape mutations, but their …

Background More effective vaccine candidates against variants of concern as a booster
dose are needed in people primed with two-dose inactivated COVID-19 vaccines. Methods …

Since the emergence of the SARS-CoV-2 Omicron variant, multiple observational studies
have reported negative vaccine effectiveness (VE) against infection, symptomatic infection …

Background Vaccination reduces COVID-19-related hospitalization among older adults.
However, how SARS-CoV-2 infection and vaccine regimens affect vaccine-elicited immunity …