Breakthrough infection risk: Moderna vaccine better than Pfizer, says study

Amid rigorous debate on breakthrough COVID infections — those that occur despite full vaccination — a US study has said Moderna’s vaccine may be more effective than Pfizer’s in this regard.

A Mayo Clinic study has suggested that the risk of a breakthrough COVID infection with the virulent Delta variant may be lower for those who took two shots of the Moderna vaccine, than those who did the Pfizer vaccine. The study, which is awaiting a full review, was reported by CNBC.

While both vaccines “strongly protect” against severe COVID infection, the difference lies in how far they prevent it in the first place, said the report.

Citing the study, the report said that in Florida last month, the risk of a breakthrough infection was found to be about 60% lower for Moderna vaccine recipients than Pfizer vaccine recipients. In Minnesota, a similar trend was seen last month, it added. While the Moderna vaccine was 76% effective at preventing infection, Pfizer’s was only 42% effective, said CNBC.

“Comparing rates of infection between matched individuals fully vaccinated with mRNA-1273 (Moderna vaccine) versus BNT162b2 (Pfizer vaccine) across Mayo Clinic Health System sites in multiple states (Minnesota, Wisconsin, Arizona, Florida and Iowa), mRNA-1273 conferred a two-fold risk reduction against breakthrough infection compared to BNT162b2,” the study authors wrote in their abstract, according to the report.

‘Wakeup call’ for US government

The ‘pre-print’ study — one that is not peer reviewed and published in an academic journal yet — was released on Sunday. American new website Axios reported on Wednesday that the Joe Biden administration is paying keen attention to the findings, and may use it as a ‘wakeup call’.

Also read: US city down to 6 ICU beds as Delta spreads tentacles

The Axios report quoted Pfizer as saying it and its partner BioNTech “expect to be able to develop and produce a tailor-made vaccine against that (Delta) variant in approximately 100 days after a decision to do so, subject to regulatory approval.”

The pharma major went on to emphasise that its vaccine is highly effective, and that it is set to develop booster shots, too, said CNBC.

Third doses authorised

Meanwhile, late Thursday, the US Food and Drug Administration (FDA) said immunocompromised Americans will be able to get a third shot of an mRNA COVID vaccine — either Pfizer’s or Moderna’s.

The programme is meant for people who did not have an ideal immune response to the first two doses, said ABC News. This includes many cancer patients, transplant recipients, people with HIV and those on immunosuppressants.