COVID Vaccine Effectiveness Falls Against South African Variant

Ralph Ellis

January 29, 2021

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

Pharmaceutical companies Pfizer and Novavax say their coronavirus vaccines work better against the coronavirus variant first found in the United Kingdom than the variant that apparently originated in South Africa.

Meanwhile, Novavax, whose vaccine is still in development, said it will start work on a new vaccine to target the South African variant. Pfizer, whose vaccine has been in wide circulation since December, said it doesn't think a new vaccine is necessary at this time.

The companies announced their testing results as the United States' first two cases of the South African variant were detected this week in South Carolina. The U.K. variant has been found in at least 26 states. Both variants appear to be more contagious than the original novel coronavirus.

A Pfizer news release said laboratory studies show its vaccine "elicits antibodies that neutralize SARS-CoV-2 with key mutations present in U.K. and South African variants."

The vaccine was "slightly" less effective against the South African variant, the news release said, but Pfizer and its European partner BioNTech "believe the small differences in viral neutralization observed in these studies are unlikely to lead to a significant reduction in the effectiveness of the vaccine."

Pfizer said it doesn't think a new kind of vaccine is necessary to battle the variants, but if there's evidence the variants are resistant to the vaccine, it will do so.

"Pfizer and BioNTech believe that the flexibility of BioNTech's proprietary mRNA vaccine platform is well suited to develop new vaccine variants if required," Pfizer said.

Novavax is one of the companies developing a COVID-19 vaccine under the government's Operation Warp Speed. It's vaccine is still in clinical trials and has not received emergency use authorization from the FDA.

In a Thursday news release, the company said its vaccine is 95.6% effective against the original coronavirus that swept the globe and 89.3% effective against the variant detected late last year in the United Kingdom.

But the Novavax vaccine was less effective against the South African vaccine. It only showed 60% effectiveness in study participants without HIV and 49.4% when HIV-positive participants were included in the study.

Still, that's good news, vaccine scientists said.

"The 60% reduced risk against COVID-19 illness in vaccinated individuals in South Africans underscores the value of this vaccine to prevent illness from the highly worrisome variant currently circulating in South Africa, and which is spreading globally," Shabir Maddi, principal investigator in the Novavax COVID-19 vaccine trial in South Africa, said.

"This is the first COVID-19 vaccine for which we now have objective evidence that it protects against the variant dominating in South Africa."

Novavax said it would start working on a vaccine to target the South African variant and will also develop a booster shot to work with the original vaccine.

The companies did not discuss how their vaccines will work against the variant that is surging in the Amazon region of Brazil. That variant was first detected in the United States this week.

In July, the U.S. government agreed to pay Novavax, a Maryland-based pharmaceutical company, $1.6 billion to produce 100 million doses of a coronavirus vaccine under Operation Warp Speed.

Both the Pfizer and Novavax vaccines are designed to work with two doses.

Modern said studies showed its vaccine, the second one now being used in the United States, is more effective against the UK variant than the South African variant.

Source

Pfizer. "IN VITRO STUDIES DEMONSTRATE PFIZER AND BIONTECH COVID-19 VACCINE ELICITS ANTIBODIES THAT NEUTRALIZE SARS-COV-2 WITH KEY MUTATIONS PRESENT IN U.K. AND SOUTH AFRICAN VARIANTS"

https://www.pfizer.com/news/press-release/press-release-detail/vitro-studies-demonstrate-pfizer-and-biontech-covid-19

Novavax. "Novavax COVID-19 Vaccine Demonstrates 89.3% Efficacy in UK Phase 3 Trial"

https://ir.novavax.com/news-releases/news-release-details/novavax-covid-19-vaccine-demonstrates-893-efficacy-uk-phase-3

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