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AstraZeneca Plc’s Covid-19 vaccine has shown limited efficacy against mild disease caused by the variant first identified in South Africa, according to early data in a small phase study.
Efficacy against severe Covid-19 cases, hospitalization and deaths had not yet been established, “as the subjects were mainly young healthy adults,” an AstraZeneca spokesperson said in a statement.
None of the study participants died or was hospitalized, according to the Financial Times, which first reported on the study’s findings. The study, with a relatively small sample size of more than 2,000 individuals, has not yet been peer-reviewed and is expected to be published Monday, the paper said. Patients in the randomized, double-blind study had a median age of 31 years.
“We believe that our vaccine can protect against serious diseases as the neutralizing antibody activity is similar to that of other Covid-19 vaccines that have shown activity against more severe diseases, especially when the dosing interval is optimized to 8-12 weeks,” The spokesman for AstraZeneca said.
Initial data suggests that other immune responses, such as T cell responses, may remain intact in the South African variant, the spokesperson added.
The variant first identified in South Africa is emerging as a major threat to the world’s prospects for ending the pandemic as countries introduce the first vaccine doses. Although vaccine makers said their photos seem to maintain effectiveness against the UK variants, which pharmaceutical companies are racing towards develop booster shots against new variants as the virus evolves.
Oxford University and AstraZeneca have started to modify their vaccine against this variant, the spokesman said. Should the need arise, they will go through clinical development so that it is ready for fall delivery.
Earlier this week, Astra’s vice president for biopharmaceutical research lowered expectations of how the vaccine would work against the variant.
“We will not be surprised to see reduced efficacy,” said Mene Pangalos. “It is to be expected that there will be less activity.”
(Updates with statement from AstraZeneca starting in the second paragraph.)