UK coronavirus strain doubling in the U.S. every 10 days, according to study

The mutant coronavirus strain first identified in the United Kingdom remains at low levels in the United States, but is doubling its reach approximately every 10 days, according to a study published by researchers on Sunday.

The study reinforced the modeling done by the Centers for Disease Control and Prevention, which predicted last month that the most contagious variant could be the dominant strain in the United States by March.

The United States still has time to take steps to slow the new strain of viruses, the researchers wrote, but warned that without “decisive and immediate public health action”, the variant “is likely to have devastating consequences for the mortality and morbidity of COVID-19 in the country. In the USA in a few months. “

The research, funded in part by the CDC and the National Institutes of Health, as well as the Canadian Institutes of Health Research, has been posted on medRxiv, a prepress server, and has not yet been peer-reviewed.

The new coronavirus strain, also known as B.1.1.7, spread rapidly across the UK and has become the dominant strain in that country, which is by some indicators the hardest hit in Europe.

Health officials said existing vaccines are likely to work against new strains, although their effectiveness may be somewhat reduced.

The study found that there are “relatively low” amounts of B.1.1.7. in the United States at the moment, but which, given its rapid spread, is “almost certainly destined to become the dominant SARS-CoV-2 strain in March 2021.”

The new strain accounted for 3.6% of coronavirus cases in the United States during the last week of January, according to the study.

The researchers noted that tracking the national spread of the strain is complicated by the lack of a national genomic surveillance program like those found in the United Kingdom, Denmark and other countries.

They wrote that they had “relatively robust” estimates for California and Florida, but data outside those states was limited.

The growth rate of the virus diverged in the two states, with B.1.1.7. seeming to spread a little more slowly in California. The study authors wrote that the strain was doubling every 12.2 days in California, 9.1 days in Florida and 9.8 days in the country.

The study supports the conclusion that the new strain is already spreading through “meaningful transmission in the community”.

The authors suggest that the virus was introduced to the country through international travel and spread via domestic travel, as millions of Americans crossed the country on Thanksgiving, Christmas and New Year holidays in the fall and winter.

The authors also found that the variant was growing slightly more slowly than in European countries, a fact that they said requires further investigation, but may be the result of a shortage of current data or other factors – including “competition from others. more transmissible variants “.

Other strains of coronavirus of concern have been detected in South Africa and elsewhere.

The researchers warned that their findings “reinforce the need” for robust surveillance in the United States of possible new and emerging variants of the coronavirus.

“As laboratories in the United States are sequencing only a small subset of SARS-CoV-2 samples, the true diversity of the SARS-CoV-2 sequence in this country is still unknown,” they wrote.

“The most established surveillance programs in other countries have provided important warnings about the variants of concern that may affect the United States, with B.1.1.7 representing only one variant that demonstrates the capacity for exponential growth,” they added.

“Only with consistent and unbiased scaling that includes all geographic and demographic populations, including those often underrepresented, together with ongoing international scientific collaborations and open data sharing, will we be able to accurately assess and follow new variants that emerge during the COVID-19 pandemic, “wrote the researchers.