Photographer: Gen Shkullaku / AFP / Getty Images
Photographer: Gen Shkullaku / AFP / Getty Images
AstraZeneca Plc’s controversial coronavirus vaccine did not provide much protection against mild disease caused by the variant that showed up in South Africa in a study that last month prompted the country to seek other immunizations.
The vaccine had an efficacy of only 10% against the variant strain, according to the study released in Tuesday New England Journal of Medicine. There were no cases of serious illness in the group that received two injections of the vaccine or in the group that received sham injections.
The study did not answer the larger question of what the vaccine stood for: whether it protected patients from serious illness and hospitalization, in part because the study participants were young. The only serious side effect noted – another important indicator as European countries are investigating reports of blood clots – was high fever after the first dose.
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South Africa has halted the roll-out of the vaccine after some preliminary data from the study was released last month. The data released Tuesday was more detailed, and the publication in a medical journal indicates it has been peer-reviewed.
The study involved approximately 2000 participants with an average age of 30 years. Elderly people are generally more affected by the infection.
The vaccine prevented about 22% of all mild to moderate cases of Covid. About 93% of the cases in the trial were caused by the South African variant. Determining the level of efficacy against the strain was a secondary goal of the study.