Study: Pfizer & Moderna Covid-19 Vaccines May Be Far Less Effective Against South Africa Variant


By Alexandra Kelley 

Despite the increasing global circulation of COVID-19 vaccines, the variants of the virus that emerged in late 2020 may disrupt the world’s mission to achieve herd immunity, according to a new study approved for publishing in the journal Nature.

Researchers specifically look at the South African COVID-19 mutation, scientifically dubbed B.1.351, analyzing whether or not these pathogens are more resistant to immune responses prompted by the available vaccines.

Samples of biological fluids, namely convalescent plasma and vaccinee sera, were collected and studied for the volume of COVID-19-neutralizing antibodies contained among volunteers who recovered from a documented COVID-19 infection. This highlights concern for potential reinfection.

When analyzing volunteer vaccinee sera — or fluid from individuals who had been fully vaccinated — the results were similarly grim; neutralizing activity was “significantly lower” against B.1.351, regardless of which vaccine patients received.

Moderna’s vaccine candidate was found to be 12.4 times less effective against the South African variant, and Pfizer’s was found to have a reduced effectiveness by about 10.3 times.

A silver lining could be that both vaccine candidates held up well against the U.K. variant of COVID-19.

“The overall findings are worrisome, particularly in light of recent reports that both Novavax and Johnson & Johnson vaccines showed a substantial drop in efficacy in South Africa,” the authors concluded.

First originating in its namesake South Africa, B.1.351 has quickly spread across the globe. The U.S. Centers for Disease Control and Prevention (CDC) reports 81 confirmed cases across 20 separate jurisdictions in the U.S. The first known case was detected in the U.S. in January 2021, with official CDC statements calling for more research on the variant.

Both the U.K. and the South African version of COVID-19 see mutation specifically in the spike protein’s binding sites, which constrains how antibodies produced by the human immune system can fight the virus.

“If the rampant spread of the virus continues and more critical mutations accumulate, then we may be condemned to chasing after the evolving SARS-CoV-2 continually, as we have long done for influenza virus,” the authors warn. “Such considerations require that we stop virus transmission as quickly as is feasible, by redoubling our mitigation measures and by expediting vaccine rollout.”

In response to the mutations and concerns over approved vaccines’ efficacy, pharmaceutical companies have issued studies to watch how the variants develop.

In January, Pfizer announced its vaccine responds well against 16 different mutations. Meanwhile, Moderna announced that it was working on developing a booster vaccine to help bridge any gaps its first vaccine misses when fighting a COVID-19 variant.


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