Where 2020 saw the development and testing of vaccines against severe acute respiratory
syndrome coronavirus 2 (SARS-CoV-2) at an unprecedented pace, the first half of 2021 has …

Background Vaccines are critical cost-effective tools to control the coronavirus disease 2019
(COVID-19) pandemic. However, the emergence of variants of the severe acute respiratory …

Background Vaccine effectiveness studies have not differentiated the effect of the delta (B.
1.617. 2) variant and potential waning immunity in observed reductions in effectiveness …

The global supply of COVID-19 vaccines remains limited. An understanding of the immune
response that is predictive of protection could facilitate rapid licensure of new vaccines. Data …

Background At interim analysis in a phase 3, observer-blinded, placebo-controlled clinical
trial, the mRNA-1273 vaccine showed 94.1% efficacy in preventing coronavirus disease …

Background There are limited data on the effectiveness of the vaccines against symptomatic
coronavirus disease 2019 (Covid-19) currently authorized in the United States with respect …

Background: To date, coronavirus disease 2019 (COVID-19) becomes increasingly fierce
due to the emergence of variants. Rapid herd immunity through vaccination is needed to …

Objective To estimate the effectiveness of mRNA covid-19 vaccines against symptomatic
infection and severe outcomes (hospital admission or death). Design Test negative design …

Background The prioritization of US health care personnel for early receipt of messenger
RNA (mRNA) vaccines against severe acute respiratory syndrome coronavirus 2 (SARS …

Objectives The mRNA coronavirus disease 2019 (COVID-19) vaccines have shown high
effectiveness in the prevention of symptomatic COVID-19, hospitalization, severe disease …