New data shows South African virus variant takes vaccine effectiveness

CHICAGO (Reuters) – Data from clinical trials on two COVID-19 vaccines show that a coronavirus variant first identified in South Africa decreases their ability to protect against disease, underscoring the need to vaccinate a large number of people as quickly as possible, scientists said. .

Vaccines from Novavax Inc and Johnson & Johnson have been greeted as important future weapons to reduce deaths and hospitalizations in a pandemic that has infected more than 101 million people and killed more than 2 million worldwide.

But they were significantly less effective at preventing COVID-19 among trial participants in South Africa, where the potent new variant is prevalent, compared to countries where the mutation is still rare, according to preliminary data released by the companies. .

“Obviously, mutants have a decreasing effect on the effectiveness of vaccines,” said Dr Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, in a briefing. “We can see that we are going to be challenged.”

Novavax reported on Thursday the results of mid-term trials which showed its vaccine to be 50% effective overall in preventing COVID-19 in people in South Africa.

This compared to the UK’s late-stage results, in which the vaccine was up to 89.3% effective in preventing COVID-19.

J&J said on Friday that a single injection of its coronavirus vaccine was 66% effective overall in a massive trial across three continents.

But there were big differences between regions. In the United States, where the South African variant was first reported this week, efficacy reached 72%, compared with just 57% in South Africa, where the new variant, known as B 1.351 , accounted for 95% of the COVID-19 cases reported in the trial.

Another highly transmissible variant discovered in the UK and now in more than half of the US states has been less able to evade the vaccine’s efficacy than its South African counterpart.

The new findings, however, raise questions about the effectiveness of Pfizer Inc’s vaccines with its partner BioNTech and Moderna Inc against the new variants. Both vaccines have been shown to be around 95% effective in trials conducted primarily in the United States before new versions of the virus were identified in other countries.

“It’s a different pandemic now,” said Dr. Dan Barouch, a researcher at Beth Israel Deaconess Medical Center at Harvard University Medical School in Boston, who helped develop the J&J vaccine.

Barouch said there are now a wide variety of new variants circulating, including in Brazil, South Africa and even the United States, which are substantially resistant to vaccine-induced antibodies.

Pfizer CEO Albert Bourla said there was “a strong possibility” that emerging variants would end up rendering the company’s vaccine ineffective.

“It is not yet … but I think it is very likely that one day it will happen,” Bourla told the World Economic Forum. The drugmaker wonders if their vaccine needs to be modified to defend against the South African variant.

“ STOP HOSPITALS FROM GOING INTO CRISIS ”

Experts said the four vaccines still have great value in their ability to reduce severe COVID-19.

“The end game is to stop death, to prevent hospitals from going into crisis – and all of these vaccines, including the South African variant, appear to be doing that in a substantial way,” said Dr Amesh Adalja , infectious disease expert at the Johns Hopkins Center for Health Security

For example, J & J’s vaccine was 89% effective in preventing serious illness in South Africa.

J&J Scientific Director Dr Paul Stoffels said he suspected that a type of immune system reaction called the T-cell response plays a protective role and could help prevent serious illness.

“We knew it to a certain extent, but it’s also better and very confirming that we can see it now at the clinic,” Stoffels said in an interview.

Nonetheless, Fauci said the declining efficacy rates underscored the need to closely monitor variants and speed up vaccination efforts before new, even more dangerous mutations emerge.

“The best way to prevent a virus from further progressing is to prevent it from replicating,” Fauci said, “and you do that by vaccinating people as quickly as possible.”