With each passing week, it becomes clearer that those who are fully vaccinated against COVID-19 nonetheless carry a risk of being infected. Recent news reports have highlighted many such “breakthrough” infections as variants of the coronavirus disease spread.
But a new study of two COVID-19 vaccines suggests that the one from Moderna may offer far more robust protection against breakthrough illness compared with the vaccine from Pfizer/BioNTech.
Researchers at the Mayo Clinic Health System who studied cases in Florida during July found that the risk of breakthrough cases was about 60% lower for Moderna vaccine recipients when compared with Pfizer recipients.
That finding is important because Florida has been a hotspot for COVID-19 cases recently, thanks to the spread of the so-called delta variant, which is a highly contagious form of the coronavirus.
The Mayo Clinic researchers also found that in Minnesota, the Moderna vaccine was 76% effective at preventing infection during July, while the Pfizer vaccine was 42% effective at preventing infection.
Similar findings emerged in states such as Wisconsin, Arizona and Iowa, leading the researchers to conclude that the Moderna vaccine “conferred a two-fold risk reduction against breakthrough infection” compared with the Pfizer vaccine.
It is important to note that the Mayo Clinic findings are from a pre-print study, meaning it has yet to go through a peer-review process or be published in an academic journal.
In addition, the researchers stressed that both vaccines “strongly protect against infection and severe disease.” They also found that both vaccines were “highly effective” against hospitalization associated with COVID-19.
This latest news about vaccine effectiveness comes around the same time as a Reuters report that the European Union is looking into possible Moderna and Pfizer vaccine side effects related to the skin and the kidneys.
The EU’s European Medicines Agency, a regulatory authority that is similar to the U.S. federal government’s Food and Drug Administration, said it was examining “a small number of cases” in which there might be a relationship between the vaccine and conditions such as:
- Erythema multiforme (an allergic skin reaction)
- Glomerulonephritis (kidney inflammation)
- Nephrotic syndrome (a kidney disorder)
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