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More than 33 million Americans have been fully vaccinated against COVID-19 – more than the number of US cases reported during the pandemic. But the proliferation of pernicious variants, some of which may partially escape vaccines, means we are not out of the woods.
New research suggests that Moderna and Pfizer injections are significantly less effective against the variant first found in South Africa, called B.1.351. This study used blood samples from vaccinated people to compare antibody responses to the original virus and the B.1.351 variant. Those who received the injections had significantly fewer antibodies capable of neutralizing B.1.351.
The study authors said the two vaccines would also likely be less effective against P.1, a variant first found in Brazil.
The table below summarizes what we know so far about the effectiveness of five vaccines in protecting people against three of the more worrying coronavirus variants.
3 variants, 3 stages
Countless versions of the coronavirus are circulating around the world, each separated by a small number of genetic mutations.
Once a series of mutations make a particular strain more efficient at infecting people, deadlier, or no longer able to evade antibodies generated by a previous vaccination or infection, geneticists call it a variant of concern.
There are three: B.1.1.7, the variant initially spotted in the UK in September; P.1, which was discovered in December; and B.1.351, which was detected in samples from South Africa dating from October.
A health worker takes a nasal swab from a patient to test for COVID-19 in Cape Town, South Africa.
Nardus Engelbrecht / AP Photos
They share a mutation that affects the shape of the virus spike protein, which it uses to invade cells. Perhaps this is why these variants are more heritable.
Studies have shown that the B.1.1.7 variant – which has been reported in 94 countries, including the United States – is 50% to 70% more contagious than its viral predecessors. Recent evidence suggests that people infected with this variant may be at a higher risk of death than those who receive other strains.
Variant B.1.351 has been reported in 48 countries and 23 US states. But studies haven’t found it to be more deadly than the original virus.
The same goes for the P.1 variant, which, according to a March study, was 40% to 120% more transmissible than previous versions of the virus. P.1 has been detected in 26 countries and 10 US states.
A nurse showing a COVID-19 vaccine produced by Chinese company Sinovac.
SILVIO AVILA / AFP via Getty Images
Research suggests that existing vaccines work to protect people against B.1.1.7 but are less effective against B.1.351 and P.1. This is probably because these two variants share a mutation that can prevent antibodies generated in response to the original virus from recognizing them.
This genetic modification is mainly absent from the B.1.1.7 variant, although British researchers have found 11 cases of B.1.1.7 with this mutation in a set of more than 200,000 samples.
B.1.351 and P.1 also have a mutation that can help the virus bind to cells more tightly.
What these variations mean to you
Pfizer and Moderna said in January that they plan to develop and test callbacks to tackle the B.1.351 variant. This means that people who have been vaccinated may need a follow-up vaccine. Until then, people who have been vaccinated or who have already contracted COVID-19 could still be at risk of infection with the B.1.351 and P.1 variants.
A nurse receives a COVID-19 vaccine in Galveston, Texas on December 15.
Mark Felix / AFP via Getty Images
However, vaccines probably still provide some degree of protection against these variants, even though they are less effective.
“The more vaccines we can put in people’s arms, the fewer global infections there are,” Kristian Andersen, immunologist at the Scripps Research Institute in California, tweeted in January. This includes infections with the B.1.351 and P.1 variants, he added.
Additionally, the variants jump between hosts in the same way as the original virus, so social distancing and the use of personal protective equipment should always help stop their spread. This is why these mitigation measures remain essential – especially since if you are exposed to a more transmissible variant, you are more likely to be infected.
“Let’s put in our genomic surveillance, better masks, more masks, much more widespread testing and screenings – and avoid congested gatherings and environments,” Andersen wrote. “Combine that with accelerated vaccine delivery and an accelerated plan for updated reminders.”
Dr. Catherine Schuster-Bruce helped bring this story to light.
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