Why COVID vaccination progress at home risks being undone by spread of variants abroad
The more opportunities the virus has to spread, the more likely it is to mutate, scientist says
Variants of the coronavirus sweeping through parts of the globe are a stark reminder that despite the increase in vaccinations in North America, there are still millions of people at risk of infection.
Allowing the virus to run amok in other countries also risks putting the entire world in jeopardy and losing any gains made through COVID-19 vaccinations, some scientists suggest.
That's because the more opportunities the virus has to spread, the more likely it is to mutate, said Dr. Priya Sampathkumar, chair of infection prevention and control at the Minnesota-based Mayo Clinic.
"If we allow infection to spread unchecked, in a month or two months or inevitably at some point in time, we'll have another variant that completely escapes all the vaccine," Sampathkumar said.
"We will be back to square one. We [will] have an entire world's population that will be completely non immune and at risk for dying."
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There are concerns that at least one variant of the virus, B1617, which was first detected in India in October 2020 and is spreading rapidly in the U.K. and has sparked outbreaks in dozens of other countries, is far more transmissible than others.
Researchers from the World Health Organization determined B1617 is spreading fast in India, making up over 28 per cent of samples from positive tests, the New York Times recently reported.
The shift suggests the variant has a higher growth rate than other variants circulating in India, with the possible exception of B117, which was first detected in the U.K.
"It should be unthinkable that more people might die of COVID after we have vaccines that could save them," tweeted Zeynep Tufekci, a sociologist and associate professor at the University of North Carolina who writes about COVID-19 issues. "Yet, now with even more transmissible variants and little vaccine equity, that's what may happen."
According to the BBC, there have been almost 8,000 cases of B1617.2, one of the subtypes of B1617, in the U.K.
In a recent New York Times column with the headline "Covid's deadliest phase may be here soon," Tufekci wrote that while places where widespread vaccinations have occurred might be safe from the severe effects of variants, "for much of the rest of the world, though, this even more transmissible new variant could be catastrophic."
"Countries like India and Nepal that had fared relatively well until recently, have fairly little immunity, and are largely unvaccinated. A more transmissible variant can burn through such an immunologically naive population very fast," she wrote.
Scientists are still trying to determine whether the variant first detected in India is more lethal, causing a larger proportion of infected people to die, or whether the spike in the number of deaths is related to the sheer number of cases, Sampathkumar said.
"I don't know whether it's more lethal or not, but what we are definitely hearing is that it's much more transmissible," she said.
That means for every two or three people who would be infected for every positive case, now everyone in the household is getting infected, Sampathkumar said.
"If India isn't contained, if South Asia isn't contained, the entire world could be plunged back to where we were last year."
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Earlier this month, scientists testifying before a U.S. House of Representatives panel warned that coronavirus variants will pose a continuing threat to the U.S., with the potential to spread quickly and blunt the effectiveness of vaccines, the New York Times reported.
Salim Abdool Karim, a professor of clinical epidemiology at the Mailman School of Public Health at Columbia University in New York, told the panel that "over the coming months, we can reasonably expect new variants to emerge that are able to escape vaccine-induced immunity, because the virus is being put under pressure from wide-scale vaccination."
Various drivers for variants
Sharon Peacock, director of the COVID-19 Genomics UK Consortium, which studies variants, said there are various drivers for the emergence of variants. One of those drivers is the uncontrolled transmissions in populations.
"Although the mutation rate is actually fairly low, if you have a very high number of infections, it doesn't really matter if it's low or not because you've got plenty of opportunity for that virus to mutate," she said in an interview with CBC News.
And if there are high rates of transmission in a population that's partially immune, she said, "you will get mutations that are selected for that and are likely to increasingly avoid the immune system."
Peacock did say that so far no variants seem to have emerged that are resistant to a vaccine.
"The way to stop those emerging, surely, is to vaccinate and drive down infection rates," she said.
"If you're a country that's vaccinated, closed [its] borders, you're going to be feeling pretty safe. But most countries don't have closed borders. And new variants will continue to emerge. And we don't know what's going to happen next in relation to new variants."
'Seeing the traumatic effects' of surge
COVAX, a global alliance co-led by the World Health Organization to provide vaccines to the world's poorest countries, warned that "the global picture is far more concerning." It said in a recent statement that if the current shortfall of vaccines is not addressed, "the consequences could be catastrophic."
"At no point in this pandemic have we seen such an acute need to look to the future challenges and not rest on the patchy achievements made so far," COVAX said in a statement.
"We are seeing the traumatic effects of the terrible surge of COVID-19 in South Asia — a surge which has also severely impacted global vaccine supplies."
For example, the COVID-19 crisis in India has had a severe impact on COVAX's supply in the second quarter of the year, to the point where, by the end of June, the alliance will face a shortfall of 190 million doses, it said.
The organization called on world leaders to provide an additional $2 billion to increase vaccine coverage in lower income countries up to nearly 30 per cent. It also said countries with the largest vaccine supplies should redirect doses to COVAX.
Amanda Glassman, executive vice-president of the Center for Global Development, a think-tank based in Washington, D.C., said high-income countries that donate vaccines to low-income countries on the verge of outbreak could at least help "limit the damage."
That means donating those vaccines "before the hospitals get full — two weeks before, three weeks before they get full."
With files from Reuters