(CN) — The World Health Organization on Monday said mutations of the novel coronavirus are cause for concern and that drugmakers may need to adjust their vaccines to fight new strains of the deadly virus.
Since the United Kingdom announced shortly before Christmas that it had identified a more contagious strain of the virus, optimism over the rollout of vaccines has been tempered by worries that new strains may make vaccines less effective.
That worry became real on Sunday when South Africa said it was temporarily halting the rollout of a vaccine produced by Oxford-AstraZeneca after a study showed it was not very good at inoculating people against the dominant strain circulating in the country.
“This is clearly concerning news, however, there are some important caveats,” said Tedros Adhanom Ghebreyesus, the WHO director-general, during a news briefing Monday at the agency's Geneva headquarters.
He pointed out that the findings about the vaccine's effectiveness against the South African strain are based on a limited study involving younger people. The WHO also noted that the vaccine has been found highly effective at combating other strains of the coronavirus found around the world.
Still, the new study is a blow to the WHO, which has made the distribution of the Oxford-AstraZeneca vaccine a centerpiece in its global vaccination efforts. Unlike new RNA-based vaccines developed by Pfizer-BioNTech and Moderna, the vaccine made by the University of Oxford and drugmaker AstraZeneca does not require ultra-cold temperatures, making it much easier to distribute in poorer nations and less developed regions.
At the news briefing, Salim Abdool Karim, an infectious disease epidemiologist and co-chair of an advisory committee on the pandemic for South Africa’s government, said the AstraZeneca study in South Africa involved 2,026 mostly young people and found that it was only 22% effective in preventing mild and moderate cases of Covid-19, the disease caused by the coronavirus. Similar studies in Brazil and the United Kingdom showed much higher effectiveness for the vaccine, leading scientists to believe that it is not good at producing the antibodies needed to fight the South African strain, classified as 501Y.V2 or B.1.351.
Karim said this strain accounts for between 80% and 90% of all the cases in South Africa. He said previous studies had suggested other vaccines might be less effective against this strain too. However, he said some vaccines, including the Pfizer-BioNTech one and another produced in China by Sinopharm, appear to be good at fighting the South African variant.
He said South Africa will now delay the rollout of the Oxford-AstraZeneca vaccine while it is better studied. For example, the vaccine maker believes it might be more effective against the 501Y.V2 strain if the interval between a first and second dose is extended.
Instead of the Oxford-AstraZeneca product, Karim said South Africa will try a vaccine produced by Johnson & Johnson.
“We don't want to end up with a situation where we've vaccinated a million people or 2 million people with a vaccine that may not be effective in preventing hospitalization and severe disease,” Karim said.
South Africa is Africa's hardest-hit nation with 1.4 million confirmed cases of Covid-19 and about 46,480 deaths linked to the respiratory disease. With colder months approaching in the Southern Hemisphere, there are fears that South Africa will be hit by a third wave of Covid-19 infections and that the South African strain will spread even faster in other parts of the continent and around the world. To slow the spread of the strain, travel from South Africa has been restricted in parts of the world. Also, many nations, such as the United Kingdom, are working hard to identify people infected with the strain.
WHO experts and vaccine specialists said the difficulties posed by new strains were expected.
“It also seems increasingly clear that manufacturers will have to adjust to the evolution of the virus, taking into account the latest variants for future shots, including boosters,” Tedros said. “We know viruses mutate and we know we have to be ready to adapt vaccines so they remain effective. This is what happens with flu vaccines.”
With the emergence of new strains of the virus, political leaders and scientists have begun to say coronavirus vaccines may become normal for years to come. Last week, German Chancellor Angela Merkel said vaccines may be needed "for many years to come" in a fashion "similar to the flu vaccine, where you re-vaccinate against the new mutation of the virus every time."
During Monday’s news briefing, Dr. Seth Berkley, the head of Gavi, a public-private initiative working with the WHO to distribute vaccines around the world, said the new strains highlight that “our scientific response needs to adapt if we're going to successfully beat this pandemic.”
“It isn't simple, it isn't going to be one strain globally,” he said. “Manufacturers must be prepared to adjust to Covid-19 viral evolution, including potentially providing future booster shots, and/or adapted vaccines, if found to be scientifically necessary. We don't know that now, but that is something that obviously needs to be carefully followed.”
The WHO is also calling for more tracking of strains and greater sharing of data on mutations around the world. Studies are also underway to see if different vaccines can be combined to ratchet up an immune response to the virus.
Kate O'Brien, the WHO head of immunization, vaccines and biologicals, said the world can expect to be buffeted by other setbacks in the fight against the virus.
“I think it is so important that we recognize that information is going to continue coming out and we really have to sail a steady ship based on the preponderance of evidence and not lurch from one particular report or another report because in science there is variability,” she said.
Courthouse News reporter Cain Burdeau is based in the European Union.
Follow @cainburdeau
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