Prof Shabir Madhi. Picture: WITS/SUPPLIED
Prof Shabir Madhi. Picture: WITS/SUPPLIED

Zurich/Johannesburg — AstraZeneca’s Covid-19 vaccine is worth using in areas hit by mutated strains of the virus, World Health Organization (WHO) officials and partners have said, countering concerns about reduced effectiveness that arose in a recent test.

There’s evidence the vaccine AstraZeneca developed with the University of Oxford could provide meaningful protection against severe disease caused by the highly infectious variant that emerged in SA, called B.1.351, according to Kate O’Brien, who heads the WHO’s vaccination division. The global health agency is preparing to decide on an emergency-use listing for AstraZeneca-Oxford shots made in India and South Korea.

“There was a very positive view about proceeding with the use of the vaccine, including in settings where variants are circulating,” O’Brien said at a briefing Monday.

SA said it would pause the shot’s rollout after a trial showed it had just 22% efficacy against the new variant identified in the country late in 2020. The country is instead accelerating its supply of vaccines from Johnson & Johnson, which has yet to gain authorisation, and Pfizer-BioNTech.

Data from an SA arm of a trial of the AstraZeneca vaccine found it had limited efficacy against mild and moderate illness, lead researcher Shabir Madhi said on Sunday. There was no conclusive data showing whether it protects against severe illness, mainly because of relatively young age among the 2,000 trial participants, he said.

The decision to halt use of AstraZeneca’s shots could slow SA’s vaccination rollout, said Salim Abdool Karim, co-chair of the nation’s Covid-19 ministerial advisory committee. The country may consider issuing the shot in stages until a clearer picture of its efficacy emerges, he said in the briefing.

It’s not surprising that the vaccine has shown more limited efficacy against mild disease in cases involving the SA variant, according to Andrew Pollard, chief investigator on the Oxford vaccine trials. What’s more important is that the shot still appears to prevent more serious problems, he said in a BBC radio interview on Tuesday.

“We are going to see new variants arise and they will spread in the population like most of the viruses that cause colds every winter, but as long as we have enough immunity to prevent the severe disease, hospitalisation and death, then we’re going to be fine,” he said.

It’s too early to dismiss the AstraZeneca vaccine, which is a very important part of the global response to the current pandemic, according to Richard Hatchett, CEO of the Coalition for Epidemic Preparedness Innovations, an organisation that’s worked to accelerate development of Covid-19 vaccines.

“We probably need to find better vaccines against the variants that are emerging,” he said at the Monday briefing, adding that when supplies increase, it may make sense to deploy vaccines to certain geographies. “We don’t have that luxury yet,” Hatchett said.



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