After a booster vaccination with the Biontech-Pfizer vaccine, the initially high protection against hospital admissions and Omikron ER visits is reduced after just a few months, according to new study data. That’s according to a Southern California study published in The Lancet Respiratory Medicine.
“Covid-19 booster injections with Pfizer/Biontech significantly improve protection against omicrons, although after three months this protection appears to diminish against ER visits and even hospitalization,” summarized the study’s lead author, epidemiologist Sara Y. Tartof, from the Kaiser Permanent Health Consortium.
For the study, researchers analyzed 11,123 hospital admissions and emergency room visits that did not result in hospitalization for an acute respiratory infection.
After three doses, the Biontech and Pfizer vaccine was 85% effective against omicron hospitalizations in less than three months. But it dropped to 55% after three months or so. In terms of emergency room admission, the effectiveness of three doses in less than three months versus Omicron was 77% but dropped to 53% after three months or more.
Similar results in Delta
For the delta variant, trends in decreasing efficacy against SARS-CoV-2 were generally similar, however, efficacy was estimated to be greater than for the omicron variant at each time point. The effect of the Biontech and Pfizer vaccine against Omicron was, on average, much greater after three doses than after two doses.
In Germany, the Permanent Commission on Vaccination currently recommends a second booster for people over 70 and people with certain previous illnesses. Health Minister Karl Lauterbach (SPD) recently campaigned in Brussels for a fourth vaccination for everyone over 60 years of age.
The EU medicines agency, EMA, stated in early April that a fourth dose is not currently needed for everyone. However, it may make sense for people over 80, given the higher risk of serious illness from Covid.