Most of the coronavirus samples analyzed in Los Angeles County last week were considered to be variants that are believed to spread more quickly, officials said.
Although the recent round of tests comes with caveats – the sample size of 73 is a fraction of the new infections being confirmed across the county each day and the samples themselves have not been selected at random – this indicates that some viral mutations continue to circulate throughout the county.
“The fact that most of the samples sampled are worrying variants suggests that these variants are increasingly widespread in our community,” said county director of public health, Barbara Ferrer, on Wednesday. “And it emphasizes the importance of adhering to security measures, such as masking, social detachment and regular hand washing to avoid increasing the chances that variants of concern will become more prevalent.”
The wider spread of the most infectious mutations, health officials worry, could potentially fuel another increase that the county, and California, cannot afford, after recently emerging from the devastating wave of autumn and winter.
Of the 73 samples analyzed at the county’s public health laboratory last week, 21 were considered to be a particularly problematic and highly contagious coronavirus variant first identified in the UK.
This variant, known as B.1.1.7, is considered 50% more transmissible than other widely circulated variants, and a study published this month in the journal Nature suggests that it is 61% more likely to cause serious illness or death.
Twenty-five other test samples showed the California variant, known to scientists as B.1.427 / B.1.429.
It, like the United Kingdom variant, has been officially dubbed a “concern variant” by the United States Centers for Disease Control and Prevention – since studies have found that the strain is about 20% more transmissible than other variants in wide range. circulation.
Ferrer said that the latest results in LA County need to be interpreted “very carefully”.
“This is a convenient sample, which means that, in some cases, we are sampling specimens because we have been asked to sample them for variants, sometimes it is because there may be an association with a cluster and we are trying to find out if there are variants with that cluster ”, She said during a briefing. “But it is not a scientifically randomly selected sample.”
However, she added that “it is probably very safe to say that there are more variants circulating now than at the beginning of the year”.
“This is what everyone is concerned about,” she said. “If we keep our case numbers low, we’ll also keep transmission of variants low.”
Of the 871 sequencing tests the county has carried out to date, 379 specimens were found to be the California variant and 76 were the UK variant, according to the numbers presented by Ferrer on Wednesday.
The county has yet to find any cases of two other worrying variants: P.1, from Brazil, or B.1.351, from South Africa.
Nationally, for the four-week period ending on February 27, 12.9% of the genomically sequenced coronavirus samples were identified as the California variant, while 9.5% were considered the UK variant, according to data of the CDC.
Times staff writer Melissa Healy contributed to this report.