Two new Covid vaccines have less efficacy against South African strain

Early data from two new coronavirus vaccine trials has indicated that they have less efficacy at protecting from the South African variant of coronavirus.

Clinical trial data showed that the vaccines from Novavax and Johnson & Johnson had significantly less efficacy at preventing coronavirus in trial participants in South Africa, where the new variant is widespread, compared with countries where the variant is less common.

Novavax reported that results from mid-stage trials on Thursday showed its vaccine had 50% efficacy overall in preventing Covid-19 among people in South Africa. In late-stage results from the UK, the vaccine had up to 89.3% efficacy.

On Friday, Johnson & Johnson said a single shot of its vaccine had 66% efficacy, judging by a large-scale trial which spanned three continents. In the US, which recorded its first cases of the South African variant this week, the vaccine’s efficacy reached 72%, but it was just 57% in South Africa, where the new variants constituted 95% of the coronavirus cases in the trial.

The trial results also raise questions over the efficacy of the vaccines currently in circulation, such as the Pfizer/BioNTech which has been distributed in the UK. While the vaccines showed high efficacy, the trials were largely undertaken before the South African variant had spread widely.

Dr Dan Barouch, a researcher at Harvard University medical school’s Beth Israel Deaconess medical centre in Boston who helped develop the Johnson & Johnson vaccine, said the new variant meant this was a “different pandemic now”.

Speaking at the World Economic Forum, Pfizer’s chief executive, Albert Bourla, said there was “a high possibility” that the new strains could eventually mean the firm’s vaccine was redundant.

“This is not the case yet … but I think it’s a very high likelihood that one day that will happen,” Bourla said. Pfizer is considering whether its vaccine needs to be altered to protect against the South African variant.

Despite the new variant, experts said that existing vaccines were still valuable in the fight against coronavirus, and Johnson & Johnson’s vaccine was 89% effective at preventing severe disease in South Africa.

“The end game is to stop death, to stop hospitals from going into crisis and all of these vaccines, even including against the South African variant, seem to do that substantially,” said Dr Amesh Adalja, an infectious disease expert at the Johns Hopkins Center for Health Security.