Fresh data show toll South African virus variant takes on vaccine

By Julie Steenhuysen

CHICAGO (Reuters) – Clinical trial data on two COVID-19 vaccines show that a coronavirus variant first identified in South Africa is lessening their ability to protect against the illness, underscoring the need to vaccinate vast numbers of people as quickly as possible, scientists said.

The vaccines from Novavax (NASDAQ:) Inc and Johnson & Johnson (NYSE:) were welcomed as important future weapons in curbing deaths and hospitalizations in a pandemic that has infected more than 101 million people and claimed over 2 million lives worldwide.

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

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

Novavax reported midstage trial results on Thursday that showed its vaccine was 50% effective overall at preventing COVID-19 among people in South Africa.

That compared with late-stage results from the United Kingdom, in which the vaccine was up to 89.3% effective at preventing COVID-19.

On Friday, J&J said a single shot of its coronavirus vaccine was 66% effective overall in a massive trial across three continents.

But there were wide differences by region. 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, made up 95% of the COVID-19 cases reported in the trial.

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

The new findings, however, raise questions about how highly-effective vaccines from Pfizer Inc (NYSE:) with partner BioNTech, and Moderna (NASDAQ:) Inc will fare against new variants. The two vaccines showed an efficacy of around 95% in trials conducted primarily in the United States before the new virus versions were identified in other countries.

“It’s a different pandemic now,” said Dr. Dan Barouch, a researcher at Harvard University Medical School’s Beth Israel Deaconess Medical Center 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, that are substantially resistant to vaccine-induced antibodies.

Pfizer Chief…