LONDON — A new and potentially more contagious variant of the coronavirus has begun to outpace other versions of the virus in Britain, putting pressure on the government to shorten people’s wait for second doses of vaccines and illustrating the risks of a faltering global immunization drive.
The new variant, which has become dominant in India since first being detected there in December, may be responsible in part for a grievous wave of infections across Southeast Asia, including Nepal, where people have been dying in hospital corridors and courtyards. But efforts to understand the variant picked up once it began spreading in Britain, one of at least 49 countries where it is present. Scientists there are sequencing half of all coronavirus cases amid a push to complete the reopening of its economy.
The preliminary results out of Britain, drawn from only a few thousand cases of the variant, contained both good and bad news, scientists said.
The variant, known by evolutionary biologists as B.1.617.2, is “highly likely” to be more transmissible than the variant behind Britain’s devastating wintertime surge, government scientists have said. That earlier variant, known as B.1.1.7, was itself considerably more contagious than the one that first emerged last year in Wuhan, China.
Public Health England report published this weekend provided signs that government scientists said were consistent with a more transmissible virus: The variant first seen in India was roughly 50 percent more likely than B.1.1.7 to be transmitted to the close contacts of an infected person. Government scientists said last week that it could be anywhere from a few percentage points to 50 percent more contagious than B.1.1.7.
Helpfully for Britain and other wealthy nations, the latest worrisome variant has emerged at a less dire moment of the pandemic. More than four out of every five people in England above the age of 65 — among the groups most vulnerable to the virus — have been given both doses of a coronavirus vaccine, driving down hospitalizations and deaths.
And a new study by Public Health England offered reassuring signs that fully vaccinated people were about as well protected from the variant first detected in India as they were from other forms of the coronavirus.
The Pfizer-BioNTech vaccine offered 88 percent protection against the variant first sampled in India, only a slight drop from the 93 percent protection given against the variant from Britain, Public Health England said. The AstraZeneca-Oxford vaccine was 60 percent effective against the variant from India, compared to 66 percent effective against the one first seen in Britain.
Other studies in England have shown little to no difference between the effectiveness of the Pfizer and AstraZeneca vaccines.