AstraZeneca's vaccine doesn't work against mutant coronavirus strain, South African government says

South Africa is halting use of the AstraZeneca vaccine due to its ineffectiveness against the mutant strain

By Matthew Rozsa
February 8, 2021 10:06PM (UTC)
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3D model of the novel Coronavirus (Getty Images)

The South African government is suspending the use of one of its COVID-19 vaccines on its citizens because it is ineffective against a mutated strain of the coronavirus known as B.1.351. 

The government announced on Sunday that the SARS-CoV-2 vaccine developed by the pharmaceutical company AstraZeneca and the University of Oxford failed to protect clinical trial volunteers from B.1.351, a more contagious mutant strain of the novel coronavirus.

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Hence, South Africa is suspending the use of that vaccine, although they said they would reconsider using it if additional studies reinforce existing ones which suggest that the vaccine could protect people against more severe cases. The government's challenge is that the existing studies included volunteers who were younger and less likely to develop severe infections, meaning they could not determine this on their own. The studies' reliability are also hindered by the fact that they did not analyze a large number of cases.

"There's plenty of uncertainty, but this is not good news, especially for countries that were hoping to use the Oxford/AstraZeneca vaccine to curb transmission of B.1.351," Dr. Dylan Morris, a postdoctoral research scholar at UCLA, told Salon by email. "It is still possible that the Oxford/AstraZeneca vaccine will reduce the severity of B.1.351 infection, and still possible that it will work better with a longer dose gap. Scientists are investigating."

He struck a cautiously optimistic note, telling Salon that the South African scientists also found that a single-shot Johnson & Johnson vaccine "showed efficacy against B.1.351 in a large clinical trial. It prevented symptoms well and prevented severe disease very well," and that although there has not been a clinical trial for mRNA vaccines "lab evidence gives us reason to be cautiously optimistic that they will hold up more like J&J than like Oxford/AstraZeneca." He also observed that the South African scientists based their conclusion in part on the lab results for the Oxford/AstraZeneca vaccine being "substantially worse" than those for other vaccines, meaning that their decision to roll out the Johnson & Johnson vaccine is "very prudent."

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The news may be a bad omen for vaccination in South Africa, but it doesn't mean the US mass vaccination strategy needs to be shifted — yet. 

"The low efficacy for the B.1.351 variant shows just how much we need to avoid more mutations, and get this pandemic under control ASAP with vaccines and mitigation strategies together," Dr. Eric Feigl-Ding, senior fellow at the Federation of American Scientists, told Salon by email. He noted that "other vaccines do work for the B.1.351 variant even if AstraZeneca doesn't."  

"We are fortunate B.1.351 is still relatively rare in the US, but we do know the more infectious B.1.1.7 variant from the UK is in the US and rising rapidly—likely to become the dominant variant by mid-to-late March," he added.

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The B.1.1.7 strain of the novel coronavirus, which originated in the United Kingdom and was first identified in September, is notable because it is unusually transmissible, has an abnormally large number of mutations (23) and has some of those mutations on the Spike protein. The Spike protein is what causes the little points on the virus' surface, like the spines of a sea urchin, which the virus uses to enter the body's cells — and which mRNA vaccines like those developed by Pfizer and Moderna target in order to inoculate people against the disease.

The South African B.1.351 mutation, by contrast, is notorious for developing a further mutation known as E484K, which seemed to correlate with vaccines being less effective in South Africa. In the United Kingdom, at least 11 individual B.1.1.7 viruses also had the E484K mutation.

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"Much of this variant's growth has been hidden in the underbelly of the old common strain's decline," Feigl-Ding wrote to Salon. "We can't get complacent. The vaccines work — we need to use the critical time window now to slow and stop the transmission before B.1.1.7 wave crashes as the dominant variant across the US."

Morris expressed a similar view, writing that "Americans are fortunate to have access to great vaccines: the mRNA vaccines, and possibly soon [Johnson & Johnson]. But the variants are still a major threat to Americans. All three are here already, and it is very possible that all three are more transmissible than the wild-type. That makes it harder to control the pandemic while we vaccinate, as places like the UK and Israel have seen."

Dr. Russell Medford, Chairman of the Center for Global Health Innovation and Global Health Crisis Coordination Center, wrote to Salon that the new information from South Africa illustrates three major points for the American people.

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"First, it is fortunate that we have multiple other vaccines, such as those developed by Pfizer, Moderna, Novavax and Johnson and Johnson, that preliminary laboratory studies show to be somewhat less effective but still protective against B.1.351," Medford explained. "Second, when necessary the technology underlying mRNA vaccines allows for the rapid development of vaccine boosters that can specifically protect against variants such as B.1.351."

He added, "Third, to prevent the spread of B.1.351 and the emergence of new and similar variants, we can and must aggressively crush quickly the circulation of the SARS-CoV2 virus, including all its variants, through mass vaccination and the rigorous adherence to mask wearing, social distancing and handwashing."


Matthew Rozsa

Matthew Rozsa is a staff writer for Salon. He holds an MA in History from Rutgers University-Newark and is ABD in his PhD program in History at Lehigh University. His work has appeared in Mic, Quartz and MSNBC.

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Astrazeneca B.1.351 Covid-19 Furthering Oxford South Africa