Qatar’s second wave of COVID-19 was a double whammy. In January, after months of relatively few cases and deaths, the Persian Gulf nation saw a surge driven by the fast-spreading B.1.1.7 variant, which was first identified in the United Kingdom. Weeks later, the B.1.351 strain, which is linked to reinfections and dampened vaccine effectiveness, took hold.
Amid this storm, researchers in Qatar have found some of the strongest evidence yet that current vaccines can quell variants such as B.1.351. Clinical trials in South Africa — where B.1.351 was first identified — had suggested that vaccines would take a hit against such variants. But this study offers a fuller picture of what countries battling such variants can expect.
People in Qatar who received two doses of the Pfizer–BioNTech vaccine were 75% less likely to develop a case of COVID-19 caused by B.1.351 than were unvaccinated people, and had near-total protection from severe disease caused by that strain.
The findings — published on 5 May in The New England Journal of Medicine1 — suggest that current RNA vaccines are a potent weapon against the most worrisome immune-evading variants. Pfizer, based in New York City, and BioNTech, in Mainz, Germany, are developing an updated RNA vaccine targeting B.1.351, as is Moderna, based in Cambridge, Massachusetts. Early results from Moderna’s efforts suggest that a booster shot of the updated vaccine triggers a strong response against B.1.351.
“I think this variant is probably the worst of all the variants we know,” says Laith Jamal Abu-Raddad, an infectious-disease epidemiologist at Weill Cornell Medicine—Qatar in Doha, who led the Qatari study. “We have the tools, despite these variants, to control at least the severe forms of infection — and this should work quite well on transmission.” ...
The researchers compared SARS-CoV-2 infection rates in vaccinated people with those in unvaccinated controls. People who received two vaccine doses were about 90% less likely to develop an infection caused by B.1.1.7, echoing findings from Israel, the United Kingdom and elsewhere. The researchers identified around 1,500 ‘breakthrough’ infections caused by the B.1.351 variant in vaccinated individuals, but only 179 of these occurred more than 2 weeks after the second dose. There were hardly any severe cases of COVID-19 caused by either B.1.1.7 or B.1.351 among fully vaccinated individuals. ...
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