CDC says effectiveness of redesigned COVID boosters increases with time
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Announcing first published data on the effectiveness of updated COVID-19 boosters, the Centers for Disease Control and Prevention (CDC) said Tuesday that the benefits of newly authorized messenger-RNA-based shots increased with time.
The CDC scientists used data from more than 360K PCR tests conducted at nearly 10K retail pharmacies for those aged 18 years and above, out of whom 34% tested positive for COVID.
5% of those with positive test results had received a bivalent booster dose, and 7% who tested negative for COVID had received a bivalent booster dose.
Comparing those who received bivalent boosters and those who opted for two or more monovalent doses, the CDC scientists said bivalent shots improved protection âwith relative benefits increasing with time since receipt of the most recent monovalent vaccine dose.â
The study is subject to several limitations, including low uptake of redesigned shots and evolving nature of the virus, which might make the findings irrelevant for future variants.
In late August, the FDA authorized the bivalent COVID-19 vaccines developed by Pfizer (NYSE:PFE)/BioNTech (NASDAQ:BNTX) and Moderna (NASDAQ:MRNA) to counter the original virus strain as well as Omicron BA.4/BA.5 subvariants.
However, as no clinical efficacy data were available for updated shots, the agency authorized the new crop of vaccines using data for bivalent vaccines adjusted for Omicron BA.1 strain.