The initially high level of protection against hospitalization and emergency room visits is reduced in Omikron only a few months after the Biontech/Pfizer booster vaccination. This is shown by new study data from Southern California, published in the journal Lancet Respiratory Medicine have been posted.
The study’s lead author was summarized by Sarah Y Tartoff, an epidemiologist at the Health Consortium Kaiser Permanente. Until then, however, some efficacy remained.
For the study, researchers analyzed 11,123 hospital admissions and emergency room visits that did not result in hospitalization due to acute respiratory infection. In the investigation period from December 2021 to February 2022, both the delta and the omicron variant were in circulation.
Protection only 55 percent after three months
Result of the Pfizer-funded study: After three doses, the effectiveness of the Biontech-Pfizer vaccine against hospitalization for omicron was 85 percent in less than three months. But it dropped to 55 percent after three months or more.
In terms of emergency room admissions, the efficacy of three doses in less than three months versus Omicron was 77 percent, but dropped to 53 percent after three or more months.
EMA: A fourth dose is not necessary for everyone at the moment
For the delta variant, trends in reduced 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.
At the beginning of April, the European Union Medicines Agency (EMA) announced that a fourth dose for all citizens is not currently necessary. However, it may make sense for people over 80 given the higher risk of severe Covid disease.
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