COVID-19 risk substantially reduced in seniors who receive 4th mRNA booster

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 variant and associated hospitalizations with among individuals aged ≥80 years.