Drop in COVID Vaccine Effectiveness Suggests Need for Boosters

Dec. 10, 2021 -- The effectiveness of the 2 astir communal COVID-19 vaccines declined implicit clip successful an older radical of patients, suggesting that booster doses whitethorn beryllium needed to support recipients implicit the agelong term, according to a caller study.

Also seen successful that radical of U.S. veterans, who had a median property of 67: Those receiving “the Moderna vaccine consistently had higher antibody levels, compared with recipients of the Pfizer-BioNTech vaccine, crossed property groups and clip since vaccination,” said Kristina L. Bajema, MD, of the CDC’s COVID-19 Response Team, and associates.

Effectiveness of the Moderna vaccine was 89.6% astatine 14-119 days aft patients had received the 2nd dose, compared with 86.0% for the Pfizer vaccine. After 120 oregon much days, vaccine effectiveness had dropped to 86.1% for Moderna and 75.1% for Pfizer, the investigators reported successful the Morbidity and Mortality Weekly Report.

Levels of the applicable antibodies -- anti-spike immunoglobulin (IgG) and anti-receptor binding domain (RBD) IgG -- showed a akin pattern: Lower aft the 120-day people for some vaccines, but higher astatine some clip periods for Moderna than for Pfizer. These differences successful antibody levels are accordant with different studies, researchers said, and whitethorn beryllium the effect of the Moderna vaccine’s higher antigen contented and its longer interval betwixt doses.

All 1,896 veterans successful the survey were enrolled portion they were hospitalized with COVID-like unwellness astatine 5 Veterans Affairs aesculapian centers astir the state (Atlanta, Houston, Los Angeles, New York City, and Palo Alto, CA). The radical included patients who tested affirmative and those who were antagonistic for COVID-19 erstwhile archetypal hospitalized; 799 yet were afloat vaccinated. About 58% of the radical was property 65 oregon older.

Both vaccines were much effectual successful younger patients: 89.4% for those nether 65 years and 72.9% for those 65 and older successful the Pfizer group, compared to 94.5% and 78.6%, respectively, for Moderna. The aforesaid drop-off successful effectiveness aft 120 days was seen for some property groups, the researchers noted.

The property effect whitethorn beryllium origin for concern.

“Overall, for some vaccine products, antibody levels successful this cohort of older U.S. veterans with precocious prevalences of underlying aesculapian conditions were substantially little than levels seen among younger, steadfast volunteers oregon wellness attraction unit successful different studies,” they said, adding that booster doses whitethorn beryllium needed “to assistance support semipermanent extortion against terrible COVID-19.”