By Pooja Toshniwal Paharia Sep 14 2022 Reviewed by Danielle Ellis, B.Sc. In a recent study published in the Annals of Internal Medicine, researchers in Singapore estimated the effectiveness of the second booster (fourth dose) vaccination with messenger ribonucleic acid (mRNA) vaccines against symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections with the SARS-CoV-2 Omicron...
