By the 4 month, the efficacy of Pfizer's Moderna booster has significantly reduced
Key Takeaways:
- By the fourth month after administration, the efficacy of the third dose of the Pfizer and Moderna mRNA vaccines has significantly decreased.
- In the first two months, vaccine efficacy against hospitalization was 91 percent, but by the fourth month, it had dropped to 78 percent after a third dose.
As per the latest study released Friday by the US Centers for Disease Control and Prevention (CDC), the efficacy of third doses of the Pfizer and Moderna mRNA vaccines wanes significantly by the fourth month after administration.
Though it's now widely accepted that vaccine efficacy declines after two doses, there's been little research on how long protection lasts after a booster.
The new research was based on over 241,204 visits to an emergency department or urgent care clinic and 93,408 more serious hospitalizations among adults with Covid-19-like illness between August 26, 2021, and January 22, 2022.
Vaccine efficacy was calculated by comparing the odds of a positive Covid test among immunized and unimmunized patients and using statistical methods to control for a calendar week, geographic area, age, level of local transmission, as well as patient characteristics such as comorbidities while adjusting for age, level of local transmission, and patient characteristics such as comorbidities.
Immunization efficacy against Covid-associated emergency department or urgent care visits was 87 percent two months after a third dose during the Omicron-predominant period but fell to 66 percent by the fourth month.
Vaccine efficacy against hospitalization was 91 percent in the first two months, but by the fourth month, it had dropped to 78 percent after a third dose.
The authors concluded, "The finding that protection imparted by mRNA vaccines waned in the months following receipt of a 3rd vaccine dose reinforces the importance of considering additional doses to maintain or improve protection."
President Joe Biden's top medical advisor Anthony Fauci stated at a White House Covid briefing on Wednesday that 4th doses are more likely to be required for subsets of individuals who mount weaker immune reactions, such as the elderly immunocompromised.
A new antibody has been approved.
On Friday, the Food and Drug Administration (FDA) approved bebtelovimab, a new lab-grown antibody treatment developed by pharmaceutical company Lilly.
The drug, which is provided as an intravenous injection that lasts at least 30 seconds, has been authorized to treat mild-to-moderate Covid in people aged 12 and up who are at high risk of developing severe disease.
The clearance was based on data from a clinical trial that showed the drug has much potential against Omicron. The FDA de-authorized Lilly's previous antibody treatment after it was ineffective against this variant.