Another COVID-19 vaccine has run into trouble in South Africa, showing less protection there than elsewhere because a SARS-CoV-2 variant that can apparently dodge key antibodies has become widespread. In the wake of the new finding, the country halted plans to next week to launch the country’s first immunization campaign with the vaccine and may instead switch to a different one.
The stakes are high globally for this particular vaccine because its makers, AstraZeneca and the University of Oxford, hope it will be widely used in developing countries; they project they can produce 3 billion doses this year for about $3 each, far more product at a far lower price than any other vaccine shown to offer protection against COVID-19.
Yet the South African trial of the vaccine, conducted in about 2000 people, found such a low efficacy against mild and moderate disease, under 25%, that it would not meet minimal international standards for emergency use.
But scientists are hopeful it might still prevent severe disease and death—arguably the most important job for any COVID-19 vaccine.
That was impossible to tell from this placebo-controlled trial because it was small and recruited relatively healthy, young people—their average age was only 31.
None of the subjects in either arm of the study developed severe disease or required hospitalization.
South Africa last week received 1 million doses of the AstraZeneca-Oxford vaccine and had planned to start to offer it to health care workers next week, which would have made it the first COVID-19 vaccine available in the country outside of clinical trials. Epidemiologist Salim Abdool Karim, who co-chairs the South African Ministerial Advisory Committee on COVID-19, said at the Sunday press conference that the rollout of the vaccine in South Africa “needs to be put on temporary hold” in light of the disappointing results.
Karim explained to Science that the J&J vaccine should be available in South Africa in roughly the same time frame, so there should be no delay in starting to protect health care workers.