The World Health Organization (WHO) decided on Wednesday that potential benefits of the COVID-19 vaccine developed by AstraZeneca and Oxford University outweigh known and potential risks, amid concerns over its efficacy against the coronavirus variant found in South Africa.
The WHO Strategic Advisory Group of Experts on Immunization (SAGE) panel said the two-dose AstraZeneca vaccine efficacy tended to be higher when the interval between doses was within the four to 12 weeks range.
It also added that although preliminary analyses based on a small sample size in South Africa indicate a marked reduction in vaccine effectiveness against mild and moderate disease, it did not allow a specific assessment of vaccine efficacy against severe COVID-19. As indirect evidence is compatible with protection against severe COVID-19, the situation remains to be demonstrated in ongoing clinical trials and post-implementation evaluations.
In view of this, WHO currently recommends the use of the AstraZeneca vaccine even if the variants are present in a country. Countries should conduct a benefit-risk assessment according to the local epidemiological situation, including the extent of circulating virus variants.
"We have made a recommendation that even if there is a reduction in the possibility of this vaccine having a full impact in its protection capacity, especially against severe disease, there is no reason not to recommend its use even in countries that have circulation of the variant," said SAGE chair Alejandro Cravioto at a briefing.
Meanwhile, SAGE cautioned that as there are currently no efficacy or safety data for children or adolescents below the age of 18 years, vaccination of individuals below 18 years of age is not recommended until such data are available.
South Africa said recently that the rollout of the AstraZeneca vaccine in the country would be temporarily put on hold until more "clinically efficacy information" of the vaccine against new COVID-19 variant becomes available. The decision came after a study showed that the AstraZeneca vaccine was less effective against the new variant found in South Africa.
