I follow the latest developments on COVID-19 and our efforts to control the pandemic or deal with it as an endemic disease. As of April 17:
The second “booster dose” helps protect people over 60: After two initial doses of the Pfizer vaccine and a booster dose, a study of 182,122 adults aged 60 and over showed that a second booster dose provided 52% protection against asymptomatic infection and 76% against COVID-related deaths 14 to 30 days after the booster. given (N English J med, April 13, 2022). Protection against harm from COVID-19 increased as the number of days after vaccination increased. The highest protection occurred on days 14 to 30 after receiving the second booster dose.
Reminders reduce hospitalization: The two-dose primary series of COVID-19 mRNA vaccines appeared to offer less protection against hospitalization due to variant Omicron infections than Alpha and Delta infections (JAMA, 2022 Apr 12;327(14):1323). A booster dose, however, was associated with increased efficacy against Omicron hospitalizations at the same high levels achieved against the earlier variants with two doses. The study included data from 11,690 adults admitted to 21 U.S. hospitals from March 11, 2021 through January 14, 2022. Both vaccine doses increased prevention of hospitalization by 85% during Alpha and Delta infections, but only by 65% during Omicron infections. Adding a third booster dose increased prevention of hospitalization to 86%. Vaccines significantly reduced all types of COVID-19 severity (BMJ, March 9, 2022; 376: e069761).
Most reactions to the COVID-19 vaccine are mild: The CDC reports that during the first six months of the US COVID-19 vaccination program, most adverse events were mild and short-lived (Lancet Infectious Diseases, March 7, 2022). Nearly 300 million doses of mRNA vaccine were administered in the United States between December 14, 2020 and June 14, 2021 (JAMA, 2022 Apr 12;327(14):1323). Of the 340,522 reports of vaccine side effects, 92.1% were classified as not serious; 6.6% as serious but not fatal; and 1.3% were deaths. The most common serious reports were shortness of breath, fever, fatigue, and headache. The most common causes of death were heart disease. Less severe reactions were more frequent after the second dose, compared to the first dose.
Vaccination against COVID-19 reduces infectious viral load: Usually, the more virus there is in a person infected with COVID-19, the more severe the illness. Viral load was measured in 600 symptomatic infected patients (natural medicine, April 14, 2022). The Delta variant caused a higher viral load than either the original virus or the Omicron variant. Vaccination significantly reduced viral load for Delta and Omicron infections, but a third booster dose was required for Omicron infections. The very high infectivity of Omicron is caused by factors other than viral load alone.
Dr. Gabe Mirkin is a villager. Learn more about www.drmirkin.com