TUESDAY, April 13, 2021 (HealthDay News) -- Two new studies out of Britain find that although the now-dominant "U.K. variant" of the new coronavirus does spread more quickly, it does not appear to lead to more severe disease in those made ill.
The findings should help allay fears that more patients will die after infection with the variant, officially labeled B.1.1.7.
Scientists published the findings online April 12 in two Lancet journals.
However, experts in the United States stressed that the findings are not yet conclusive, and certainly no reason for people to relax their vigilance against SARS-CoV-2.
"We should interpret these findings cautiously, as there is conflicting evidence about the severity [of disease] with similar numbers," said Dr. Eric Cioe-Peña, who directs global health at Northwell Health, in New Hyde Park, N.Y.
"The take-home message is again clear: B.1.1.7 is a more contagious variant that poses a more clear and present threat to the state of the world and the chances of ending this pandemic," he said. "It is of the utmost importance as this variant, because of how contagious it is, becomes the dominant COVID-19 infection around the world that we focus on mask wearing, distancing and vaccination now more than ever."
Earlier this month, Dr. Rochelle Walensky, director of the U.S. Centers for Disease Control and Prevention, announced that, "based on our most recent estimates from CDC surveillance, the B.1.1.7 variant is now the most common lineage circulating in the United States."
The variant emerged in the United Kingdom late last year and set off alarm bells, as it appeared to spread more easily. There were also concerns that B.1.1.7 might be more virulent, meaning that it might also trigger more severe and potentially lethal illnesses compared to prior variants.
To help sort these issues out, British researchers looked at data spanning the period between September and December of 2020, when B.1.1.7 was first spotted and began to spread across England.
In one study, published in The Lancet Infectious Diseases, researchers looked at two factors -- viral load in blood samples, and the severity of COVID-19 illness -- in 341 Britons infected with SARS-CoV-2 during November and December. Fifty-eight percent of the patients carried the B.1.1.7 variant while the other 42% did not.
"We found no evidence that the B.1.1.7 variant was associated with [increased risk of] severe disease or death," concluded a team led by Dr. Eleni Nastouli, of University College London. The study showed that 36% of people with B.1.1.7 became severely ill or died, compared to 38% of those with other strains, a negligible difference.
However, there was some bad news, too: "We believe that B.1.1.7 infections were associated with higher viral loads than were non-B.1.1.7 infections in this study," Nastouli's group noted.
In a comment accompanying the study, a team of three experts from the National Centre for Infectious Diseases in Singapore said that higher viral loads could help explain why the new variant appears to be more easily transmitted between people.
A second study was published in The Lancet Public Health. It involved almost 37,000 British users of the COVID Symptom Study phone app. All had tested positive for COVID-19 between late September and late December of last year, a period when B.1.1.7 was known to be spreading throughout England.
Again, the study found no difference in symptom severity between people who contracted B.1.1.7 versus those who'd gotten another variant, said a team co-led by Dr. Claire Steves, of King's College London.
And there was another piece of welcome news from the study: The new viral variant "doesn't appear to escape immunity gained by exposure to the original virus," Steves said in a journal news release.
Just 0.7% of people who'd previously tested positive for coronavirus infection went on to get infected again, the team said. That suggests that prior immunity to SARS-CoV-2 does seem to be maintained even when B.1.1.7 is in the mix.
However, as was seen in the other study, the British variant does appear to spread about 35% more easily than prior variants, Steves' group said.
Writing in a journal comment, Dr. Britta Jewell, from Imperial College London, said the study "adds to the consensus that B.1.1.7 has increased transmissibility, which has contributed in large part to the sharp rise in cases in the U.K. over the study period."
Another U.S. expert offered one note of caution, however.
"The studies provide more information on this more contagious variant and, unlike some other studies, do not show increased severity," said Dr. Amesh Adalja, senior scholar at the Johns Hopkins Center for Health Security, in Baltimore.
But he believes it's still too early to say for sure that B.1.1.7 does not lead to more serious illness.
One thing is clear, Adalja said: "The studies underscore the need to accelerate vaccination to prevent its further spread."
Find out more about COVID-19 variants at the U.S. Centers for Disease Control and Prevention.
SOURCES: Eric Cioe-Peña MD, director of global health, Northwell Health, New Hyde Park, N.Y.; Amesh Adalja, MD, Center for Health Security, Johns Hopkins University, Baltimore; The Lancet Infectious Diseases and The Lancet Public Health, studies and news release, April 12, 2021