A highly transmissible COVID-19 variant that emerged in Brazil and has now been found in at least 20 countries can reinfect people who previously recovered from the disease, scientists said on Tuesday.
In a study of the mutant virus’s emergence and its spread in the Amazon jungle city of Manaus, the scientists said the variant – known as P.1 – has a “unique constellation of mutations” and had very rapidly become the dominant variant circulating there.
Out of 100 people in Manaus who had previously recovered from infection with the coronavirus, “somewhere between 25 and 61 of them are susceptible to reinfection with P.1,” said Nuno Faria, a virus expert at Imperial College London, who co-led the research which has not yet been peer reviewed.
The scientists estimated that P.1 was 1.4 to 2.2 times more transmissible than the initial form of the virus.
Speaking to a media briefing about the findings, Nuno said it was too early to say whether the variant’s ability to evade immunity from previous infections meant that vaccines also would offer reduced protection against it.
COVID-19 is caused by a virus called SARS-CoV-2, and as it spread around the world, it mutated into new forms that are more quickly and easily transmitted through small water droplets in the air. Canadian health officials are most worried about variants that can slip past human immune systems because of a different shape in the spiky protein that latches onto our cells. The bigger fear is that future mutations could be vaccine-resistant, which would make it necessary to tweak existing drugs or develop a new “multivalent” vaccine that works against many types, which could take months or years.
Not all variants are considered equal threats: Only those proven to be more contagious or resistant to physical-distancing measures are considered by the World Health Organization to be “variants of concern.” Five of these been found in Canada so far. The WHO refers to them by a sequence of letters and numbers known as Pango nomenclature, but in May of 2021, it also assigned them Greek letters that experts felt would be easier to remember.
ALPHA (B.1.1.7)
- Country of origin: Britain
- Traits: Pfizer-BioNTech and Moderna vaccines are still mostly effective against it, studies suggest, but for full protection, the booster is essential: With only a first dose, the effectiveness is only about 66 per cent.
- Spread in Canada: First detected in Ontario’s Durham Region in December. It is now Canada’s most common variant type. Every province has had at least one case; Ontario, Quebec and the western provinces have had thousands.
BETA (B.1.351)
- Country of origin: South Africa
- Traits: Some vaccines (including Pfizer’s and Oxford-AstraZeneca’s) appear to be less effective but researchers are still trying to learn more and make sure future versions of their drugs can be modified to fight it.
- Spread in Canada: First case recorded in Mississauga in February. All but a few provinces have had at least one case, but nowhere near as many as B.1.1.7.
GAMMA (P.1)
- Country of origin: Brazil
- Traits: Potentially able to reinfect people who’ve recovered from COVID-19.
- Spread in Canada: B.C. has had hundreds of cases, the largest known concentration of P.1 outside Brazil. More outbreaks have been detected in Ontario and the Prairies.
DELTA (B.1.617 AND B.1.617.2)
- Country of origin: India
- Traits: Spreads more easily. Single-dosed people are less protected against it than those with both vaccine doses.
- Spread in Canada: All but a few provinces have recorded cases, but B.C.’s total has been the largest so far.
LAMBDA (C.37)
- Country of origin: Peru
- Traits: Spreads more easily. Health officials had been monitoring it since last August, but the WHO only designated it a variant of concern in June of 2021.
- Spread in Canada: A handful of travel-related cases were first detected in early July.
If I’m sick, how do I know whether I have a variant?
Health officials need to genetically sequence test samples to see whether it’s the regular virus or a variant, and not everyone’s sample will get screened. It’s safe to assume that, whatever the official variant tallies are in your province, the real numbers are higher. But for your purposes, it doesn’t matter whether you contract a variant or not: Act as though you’re highly contagious, and that you have been since before your symptoms appeared (remember, COVID-19 can be spread asymptomatically). Self-isolate for two weeks. If you have the COVID Alert app, use it to report your test result so others who may have been exposed to you will know to take precautions.
Need more answers? Email audience@globeandmail.com
“There’s no concluding evidence really to suggest at this point that the current vaccines won’t work against P.1,” Faria said. “I think (the vaccines) will at least protect us against disease, and possibly also against infection.”
Scientists around the world are on guard against new mutated forms of the coronavirus that could spread more easily, or be harder to fend off with existing vaccines.
The research, conducted with scientists at Brazil’s São Paulo and Britain’s Oxford universities, suggested that the P.1 variant had probably emerged in Manaus in early November 2020.
The first infection with it was identified on Dec. 6, Faria said. “We then looked at how rapidly P.1 overtook other lineages, and we found that the proportion of P.1 grew from zero to 87 per cent in about eight weeks.”
The large number of COVID-19 infections in some places makes it more likely for new variants of the virus to emerge. Science Reporter Ivan Semeniuk explains how vaccines may not be as effective against these new strains, making it a race to control and track the spread of variants before they become a dangerous new outbreak.
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