Up Against Mutants, WHO Says AstraZeneca Vaccine Is Still A Good Bet
The World Health Organization says countries should move forward with using the Oxford/AstraZeneca COVID vaccine even in places with variant strains of the virus.
WHO's Strategic Advisory Group of Experts on Immunization, which is known as SAGE, today issued new interim recommendations for the AstraZeneca vaccine specifically to address concerns about its effectiveness in South Africa. This week South Africa announced that it was delaying the start of its first nationwide immunization campaign after a small study suggested that the AstraZeneca product is less effectiveagainst a form of the virus that now makes up nearly 90% of all cases in South Africa.
"We don't want to end up with a situation in which we vaccinate a million or 2 million people with a vaccine that's not effective in preventing hospitalization and severe disease," said epidemiologist Salim Abdool Karim, one of the South African government's top advisers on COVID-19, said in explaining the decision to delay the distribution of the AstraZeneca vaccine.
In their new recommendations, the SAGE advisory panel acknowledges that preliminary results from that pivotal South Africa trial "indicate marked reduction in vaccine effectiveness against mild and moderate disease."
The WHO panel, however, warned that the study didn't show whether or not the vaccine was still effective against severe cases of COVID in South Africa. They said other evidence suggests that the AstraZeneca vaccine would continue to offer some level of protection even against the new variants in South Africa and elsewhere.
"Considering all these factors," said Dr. Alejandro Cravioto, the chair of the SAGE committee, "even if there is a possibility that this vaccine has a reduction in efficacy, we see no reason not to use it, even in countries with variants."
Dr. Katherine O'Brien, the vaccinologist who is head of immunization at WHO, summed up the new guidance this way: "The advice from SAGE ... and taken on board now by the WHO ... is to proceed with the vaccine even in the presence of variants."
In the immediate wake of the study results, South Africa said it plans to switch from AstraZeneca to Johnson & Johnson's vaccine for its primary vaccination campaign. The plan would be to still rollout some of the AstraZeneca but in limited quantities and to monitor recipients closely to see how well it's working.
The news from SAGE is highly significant as more and more coronavirus variants are found around the world. It's also significant because of the importance of AstraZeneca in the overall effort to vaccinate people globally.
"The Oxford AZ vaccine is one of the main vaccines," said Soumya Swaminathan, WHO's chief scientist, during the unveiling of the new guidance today. "It's going to be procured in hundreds of millions of doses and distributed around the world."
In terms of doses that have so far been purchased, AstraZeneca is currently the world's largest source of COVID vaccines, scheduled to deliver more than 2 billion doses this year. The majority of AstraZeneca's production lines are slated for low- and middle-income countries. AstraZeneca's product is attractive to officials in many lower-resource settings because it's cheap and can be stored in conventional refrigerators. The next leading manufacturer globally is Pfizer with commitments of half that — roughly 1 billion doses.
Despite the assurance by SAGE today that vaccines remain effective even in places with widespread transmission of new variants, the panel continues to be concerned about how the virus is mutating. But the SAGE recommendation stated that in most places — even places where variants are being detected — the immunizations continue to be effective, particularly in preventing hospitalizations and deaths from the disease.
Swaminathan warned front line workers and people at high risk from COVID not to wait for the perfect vaccine.
"A vaccine now is better than waiting for something potentially that may come down the road after six months or a year," she said. "So anything's that's being approved by WHO and that's available in your country, please do take it."
SAGE also said in this new document that the AstraZeneca vaccine is safe for people over the age of 65. There had been some debate earlier about limited data on the effectiveness of the vaccine in older people, but WHO now says they see no reason not to make it available to the elderly.
A more sweeping stamp of approval for AstraZeneca could be coming in the next few weeks. WHO is currently considering granting an "Emergency Use Listing" or EUL, to the product. Currently the only COVID vaccine with such an authorization is the one from Pfizer/BioNtech. If the World Health Organization grants an EUL to AstraZeneca, far more countries will be able to start distributing the vaccine. What's more, AstraZeneca's product would then become eligible for the COVAX program, run by WHO and GAVI, the vaccine alliance, to try to make sure limited supplies of vaccines are available equitably around the world. COVAX also is offering vaccines for free to the poorest countries in the world.
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