South Africa stopped a planned disbursement of the AstraZeneca COVID-19 vaccine Monday following data reports showing minimal protection against mild infection from one strain of the virus.
Scientists from the University of Witwatersrand and the University of Oxford reported in a prior-to-peer analysis that the AstraZeneca vaccine offered minimal protection against mild or moderate COVID-19 infection in the South African variant among young people, Reuters reported.
“This study confirms that the pandemic coronavirus will find ways to continue to spread in vaccinated populations, as expected,” said Andrew Pollard, chief investigator on the Oxford vaccine trial.
The analysis of infections involving the South African variant showed there was a 22% lower risk of developing mild-to-moderate COVID-19 if vaccinated with the AstraZeneca shot compared to those given a placebo.
While a previous Oxford study found the AstraZeneca vaccine to be roughly 70% effective, researchers cast doubt on its ability to protect against mild-to-moderate infections of the South African variant known as 20I/501Y.V2 or B.1.351, which is the dominant strain in the region.
The optics of the findings suggests vaccines will protect recipients in vulnerable populations against severe infections and possibly fatal outcomes, though the inability to stop all mild infections could mean updated booster shot variants will need to be facilitated to the public to keep up with mutating strains.
“This is the same issue that is faced by all of the vaccine developers, and we will continue to monitor the emergence of new variants that arise in readiness for a future strain change,” said Sarah Gilbert, professor of vaccinology at Oxford.
Lead investigator of the AstraZeneca trial in South Africa, professor Shabir Madhi, said the vaccine was similar to Johnson & Johnson’s effectiveness, which showed a reduction in severe illness by nearly 89%.
The strain of virus mutation in South Africa has been detected in 41 countries including the United States, and other variants have been discovered in the United Kingdom and Brazil.
