The World Health Organization (WHO)’s expert group on immunisations remains confident in the Oxford/AstraZeneca vaccine’s efficacy against severe SARS-CoV2 disease – despite the enormous worldwide concerns triggered by a small South African study that showed it had little effect in stemming mild disease from the B.1.351 variant first identified in that country.

“It is very clear that the vaccine has efficacy against severe disease, hospitalizations and deaths,” Dr Katherine O’Brien, WHO director of Immunization, told the body’s bi-weekly media briefing on Monday after WHO’s Strategic Advisory Group of Experts on Immunization (SAGE) meeting to decide on whether to grant the vaccine an emergency use license earlier in the day. 

“There is also evidence that the likelihood of meaningful impact against severe disease is a very plausible scenario against the B.1.351 [South African identified] variant,” O’Brien added, explaining that SAGE had met earlier in the day with investigators from Oxford/ AstraZeneca trials in the UK, Brazil and South Africa.

Stressing that the situation was dynamic, O’Brien said that evidence unfolding from the trial of people with mild disease, might seem to contradict expert opinions that the vaccine could still prevent  severe illness – but that was because “we’re painting the picture in parts and pieces and bits”.  So  far the ongoing trials have not yielded clear evidence of the AstraZeneca’s efficacy on the South African variant. 

Last Friday, WHO officials said that they would be set to make a decision on approving the AstraZeneca vaccine for widespread rollout by the Global COVAX facility sometime this week.

WHO Director General Dr Tedros Adhanom Ghebreyesus described as “concerning” the news that the AstraZeneca vaccine was “minimally effective at preventing mild to moderate disease caused by a variant first identified in South Africa”.

COVAX Suppliers Need To Be Prepared to Adjust Products To Viral Evolution

Meanwhile, Dr Seth Berkley, CEO of the vaccine alliance, GAVI, stressed that pharma manufacturers supplying vaccines to the global COVAX facility “must be prepared to adjust to COVID-19’s viral evolution, including potentially providing future booster shots and or adaptive vaccines, if found to be scientifically necessary”.

“COVAX has signed advanced purchase agreements with AstraZeneca and the Serum Institute of India, and we’ve published plans to distribute near nearly 350 million doses in the first half of the year, hopefully starting later this month, should the emergency use listing be forthcoming,” said Berkley, who added that while COVAX was currently dependent on AstraZeneca and Pfizer vaccines, other vaccines would be added to its portfolio later in the year.

Richard Hatchett, CEO of  the Coalition for Epidemic Preparedness Innovations (CEPI) stressed that a diversity of vaccine candidates “provides us with a large number of tools which we need to explore to see which works best against the variants.”

“We can also look potentially at combinations of the vaccines and of course we must accelerate the development of new strain-specific vaccines. A large number of companies have already begun to undertake that work,” said Hatchett.

Image Credits: AstraZeneca, WHO.