Omicron boosters are weaker against emerging COVID variants – study
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A newly published study has indicated that updated mRNA-based COVID boosters from Pfizer (NYSE:PFE)/BioNTech (NASDAQ:BNTX) and Moderna (NASDAQ:MRNA) generated a weaker immune response to fast-emerging subvariants, BQ.1.1 and XBB.1.
According to the latest data from the Centers for Disease Control and Prevention (CDC), BQ.1.1 looks to become the dominant COVID strain in the U.S., making up an estimated ~32% of cases, while B.A. 5 accounted for ~14% of infections.
The CDC data for the week ending Saturday indicated that XBB.1 is also gaining ground, leading to ~6% of cases, compared to ~4% a week ago.
The lab-based study conducted by Scientists at the University of Texas Medical Branch and published in Nature Medicine on Tuesday found that updated booster shots led to neutralizing antibodies that were about four times lower for BQ.1.1 compared to BA.5.
The neutralizing antibodies are essential in the immune system, as they prevent the COVID virus from invading human cells.
However, the individuals with prior COVID infections had a strong protection against BQ.1.1 after an updated booster, showing antibody titers nearly four times higher than those without previous infection.
The bivalent boosters performed even weaker against XBB.1, leading to antibody titers more than eight times lower than those against BA.5.
The study was based on blood samples of 29 people with no history of COVID infection and who received the Omicron booster, 23 samples from people who received the booster but had a prior infection, and 25 individuals who received the unadjusted mRNA-based booster.
In November, Pfizer (PFE)/BioNTech (BNTX) announced that their updated boosters for BA.4/BA.5 outperformed the original boosters against emerging Omicron subvariants, including BQ.1.1.
Days earlier, Moderna (MRNA) said that its updated boosters led to a "robust neutralizing activity" against BQ.1.1 but with a nearly five-fold decline in antibody titers compared to BA.4/BA.5.