Pfizer, Moderna Vaccines Aren’t the Same; Study Finds Antibody Differences
upstart writes:
Pfizer, Moderna vaccines aren't the same; study finds antibody differences:
The mRNA-based COVID-19 vaccines made by Pfizer/BioNTech and Moderna have proven highly effective at priming our immune systems to fight the pandemic coronavirus-preventing substantial amounts of infection, severe disease, and death throughout several waves of variants. But despite their similar design and efficacy, the two vaccines are not exactly the same-and our immune systems don't respond to them in the same way.
An early hint of this came from some real-world data that found startling differences in the effectiveness of the two vaccines, despite both shots performing nearly identically in Phase III clinical trials, with efficacies of 95 percent and 94 percent. Amid last year's delta wave, a Mayo Clinic study found that Pfizer's effectiveness against infection dipped to 42 percent while Moderna's fell to 76 percent.
Both vaccines generate strong levels of neutralizing antibodies, which can bind to the virus and prevent it from infecting cells. But according to the study, the vaccines generated different antibody profiles overall. Specifically, the antibody response to the Pfizer/BioNTech vaccine skewed to a class of antibodies called IgG and IgM, which are often found in the blood. The Moderna vaccine, meanwhile, generated relatively elevated levels of IgA antibodies, a class of antibodies generally found on mucosal surfaces, such as the respiratory tract-where SARS-CoV-2 infections begin. Additionally, the Moderna vaccine spurred relatively higher levels of antibodies that activate immune cells called natural killer cells. It also generated higher levels of antibodies that activate immune cells called neutrophils to ingest and kill (phagocytize) invading germs.
Journal Reference:
Fernando P. Polack, Stephen J. Thomas, Nicholas Kitchin, et al. Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine [open], New England Journal of Medicine (DOI: 10.1056/NEJMoa2034577)
Lindsey R. Baden, Hana M. El Sahly, Brandon Essink, et al. Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine [open], New England Journal of Medicine (DOI: 10.1056/NEJMoa2035389)
Just a moment..., (DOI: https://www.science.org/doi/10.1126/scitranslmed.abm2311)
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