6,7. Real-world studies have since found reduced effectiveness of COVID-19 vaccines against infection or mild disease with the Omicron variant8,9,10. Receipt of a 3rd dose improves protection; however, this appears to wane rapidly from the second month after vaccination8. Evidence on protection...
This case-control study estimates the effectiveness of COVID-19 vaccines against symptomatic infections due to the Delta and Omicron variants and severe
The vaccines were amazingly effective in preventing COVID-19, saved a large number of lives, and changed the impact of the pandemic. Continued acquisition of mutations in the virus, from natural evolution in response to interaction with the immune response among the human population, led to the...
in line with previous studies involving other vaccines and age groups, the vaccination program alone is unlikely to suppress viral circulation. However, this vaccine was 59.2% effective against COVID-19-hospital
Monitoring the effectiveness of COVID-19 vaccines against SARS-CoV-2 infections remains important to inform public health responses. Estimation of vaccine effectiveness (VE) against serological evidence of SARS-CoV-2 infection might provide an alternative measure of the benefit of vaccination against inf...
Background A rapid increase in coronavirus disease 2019 (Covid-19) cases due to the omicron (B.1.1.529) variant of severe acute respiratory syndrome coronavirus 2 in highly vaccinated populations has aroused concerns about the effectiveness of current vaccines. Methods We used a test-negative case...
focusing efforts to maximize uptake of vaccinations and reductions in transmission, hospitalizations, and deaths. To turn the tide on the COVID-19 pandemic, it is necessary to follow the virus—and use vaccines to shut the virus down where it is causing the most harm. That means taking vaccin...
With so much focus on the results of COVID-19 vaccines, it leads people to ask: what's the difference between "effectiveness, "efficacy," and "efficiency"?
The SARS-CoV-2 Omicron variant has demonstrated enhanced transmissibility and escape of vaccine-derived immunity. Although first-generation vaccines remain effective against severe disease and death, robust evidence on vaccine effectiveness (VE) against
Data on effectiveness and protection duration of Covid-19 vaccines and previous infection against general SARS-CoV-2 infection in general populations are limited. Here we evaluate protection from Covid-19 vaccination (primary series) and previous infecti