[ad_1]
The Centers for Disease Control and Prevention released data on Friday indicating that the level of protection against Covid hospitalizations offered by the Pfizer-BioNTech vaccine declined significantly over the four months following full inoculation.
The data was released hours before a Food and Drug Administration scientific advisory committee recommended allowing booster injections for Pfizer coronavirus vaccine recipients aged 65 or older or at high risk of. Severe Covid-19, at least six months after the second. Pull.
The new study found that from two weeks after recipients received their second dose – a time at which they are normally considered fully immunized – to four months later, the Pfizer vaccine was 91% effective in preventing hospitalization. Beyond 120 days, however, its effectiveness dropped to 77%.
The Moderna vaccine showed no comparable decrease in protection over the same period: it was 92% effective against hospitalizations four months after recipients were vaccinated, a level virtually identical to its 93% effectiveness before that date. .
The study found that an insufficient number of participants had received the Johnson & Johnson single-injection vaccine to compare its performance. Overall, however, the Johnson & Johnson injection was 71% effective in preventing hospitalizations.
The CDC study released Friday supported others who suggested the Pfizer vaccine may offer less protection against hospitalization over time. But the available data are far from unanimous.
Other studies have shown that Pfizer’s effectiveness against hospitalization has remained above 90%, despite the spread of the Delta variant and the length of time since people received their second injection. Pfizer said data from Israel suggests a decrease in effectiveness against serious illness, although it appears Israel and the United States define “severe illness” differently.
The CDC’s latest study was based on an analysis of about 3,700 adults hospitalized across the United States from March through August.
People with weakened immune systems, who usually don’t respond as well to vaccines, were excluded from the study. Nonetheless, the vaccinated patients tended to be older people – the Pfizer cohort had a median age of 68 – and it was not clear whether the effectiveness of the vaccine changed much in the younger age groups. Previous studies have shown lower levels of protection in the elderly.
The study authors said that the difference in performance of the Moderna and Pfizer vaccines could come from higher doses of mRNA in Moderna injections or the four-week gap between Moderna vaccine doses. (The Pfizer vaccines were given three weeks apart.) It is also possible, they said, that other unnoticed differences in the study participants receiving either injection may also have been influence the results.
[ad_2]
Source link