That’s according to a study from Southern California published in The Lancet Respiratory Medicine. “Covid-19 booster shots with Pfizer/Biontech significantly improve protection against omicrons, although after three months this protection appears to diminish against emergency department visits and even hospitalizations,” summarized the study’s lead author, Epidemiologist Sara Y. Tartof of the Health Consortium Kaiser Permanente, according to the release. Even then, however, a certain effectiveness remained.
For the study, the researchers analyzed 11,123 hospital admissions and emergency room visits that did not result in hospitalization for an acute respiratory infection. In the investigation period from December 2021 to February 2022, both the delta and the omicron variant were in circulation.
The results of the Pfizer-funded study: After three doses, the effectiveness of the Biontech/Pfizer vaccine against hospitalizations for omicron was 85 percent within the first three months. But it dropped to 55 percent after three months or more. In terms of emergency room visits, the effectiveness of three doses in less than three months versus Omicron was 77 percent, but fell to 53 percent after three months or more.
Efficacy significantly higher after three doses
For the delta variant, trends in decreasing efficacy against SARS-CoV-2 were generally similar, however, efficacy was estimated to be higher than for the omicron variant at each time point. On average, the effect of the Biontech/Pfizer vaccine against Omicron was significantly higher after three doses than after two doses.
In Austria, the National Vaccination Committee (NIG) recommends a fourth vaccination only for risk groups. This applies to people over 80 in general and to people over 65 with previous illnesses. They should be immunized again at the earliest four months, ideally six months after the third sting. However, everyone else should not be denied a vaccination either. At the beginning of April, the EU medicines agency EMA declared that a fourth dose for all citizens is currently not necessary. However, it could make sense for people over 80 years of age given the higher risk of severe Covid disease.
Source: Nachrichten
