Ig Report Posted in Weekly report of morbidity and mortalityScientists at the US Centers for Disease Control and Prevention (CDC) present the first real evidence of the effectiveness of a bivalent booster shot presented by the CDC and the US Food and Drug Administration (FDA). authorized in September.
The researchers concluded that the bivalent enhancer, which contains genetic material from both the original SARS-CoV-2 virus and the Omicron BA.4/5 variants, is effective in protecting people from severe COVID-19. The relative efficacy among people ages 18 to 49 who received the bivalent booster — compared to those who received more than two injections of the original vaccine — ranged from 30% if their last original vaccine dose was two to three months ago, to 56% if The last original vaccine dose was more than eight months before the new dose. The effectiveness was slightly lower for the elderly, ranging from 28% to 48% among those 50 and older.
The fact that the vaccine’s efficacy has increased over time since the last original vaccine dose shows that the new booster compensates for diminished levels of virus-fighting antibodies, the researchers write.
The data came from the National Program for Increasing Community Access to Testing, which provides free COVID-19 tests at pharmacies across the country. Between September 14 and November 11, more than 360,000 tests for SARS-CoV-2 were conducted at nearly 1,000 sites, and people were asked to report their vaccination status and previous infection history. During that time, Omicron BA.4/5 variants dominated, but newer variants, including BQ.1 and BQ.1.1which is now represented nearly 50% of cases in the United States, is starting to increase. The researchers say that the data during the periods when only BA.4/5 dominated were not significantly different regarding the effectiveness of the Omicron booster when compared to the periods when the other variables appeared. However, the researchers acknowledge that the results may change as new variables take over.
Other researchers are looking at how the updated bivalent enhancer affects immunity—not only to the variants it targets, but also to earlier and possibly newer variants that evolved from BA.4/5. Some data They suggest that vaccine-induced immunity may provide higher levels of virus-neutralizing antibodies than infection with a virus, perhaps because the immune system sees and reacts to vaccines differently than it does to pathogens such as viruses. Each vaccine may also help the immune system become more efficient at recognizing and inactivating the virus.
The study authors say the current real-world findings point to the need to keep up with COVID-19 vaccines, including getting the latest booster from Omicron. The study authors write that the bivalent boosters “provide protection against symptomatic SARS-CoV-2 infection during circulating BA.4/BA.5 and its sublines and restore protection that was observed to wane after receiving the monovalent vaccine.”
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