Los Angeles County Public Health officials announced today that the county of 10 million people had finally begun to experience a trend that has already hit many parts of the United States: a rapid rise in the number of Covid cases attributed to the more transmissible Omicron BA.2 variant.
Per L.A. County:
Although the current sequencing sample represents a small fraction of all cases, it indicates that between February 27- March 5, 14.7% of sequenced cases were the BA.2 Omicron sub-lineage in LA County. This is an increase from 6.4% of sequenced cases in the prior week.
Just last week, the county’s director of Public Health, Barbara Ferrer, described the increases in BA.2 as “a gradual growth.” Things seem to have changed. The ascent from 6.4% of sequenced cases to 14.7% means an overall 129.68% increase in the variant. By almost any measure, that is not gradual growth.
Dr. Anthony Fauci expressed concern on Sunday that the rapid rise in cases in Europe, which was preceded by a rapid rise in BA.2 sequences, could become the pattern stateside. In the U.K., for instance, the number of recorded Covid cases has risen from a recent low 7-day average of 33,000 on February 25 to over 106,000 yesterday.
“We are closely tracking the information from Europe, as patterns seen in Britain, in particular, are historically seen in the U.S. a few weeks later,” said Ferrer last week.
“It’s challenging to tease out the role of BA.2 in the increasing case counts in Europe. BA.2 arrived in each go these countries at a different time, but the rising case counts are happening at a similar time across most of Europe, which might suggest that the circulation of BA.2 in these other countries is not the only factor in increasing case counts,” she continued. “The increasing case counts came shortly after rescinding many public health measures that were designed to limit Covid-19 transmission in many of these countries. And it also is happening at a time that may be influenced but the potential waning of protection offered by the vaccines.”
It may not matter if Ferrer’s evaluation is correct, since nearly all Stateside restrictions have now also been lifted.
Numbers released Tuesday by the CDC indicate that the percentage of new Covid cases across the United States tied to BA.2 has jumped from 23% in early March to 35% this week. On the positive side, that means the rate of increase has slowed from two 100% jumps over the previous month to a little less than 50% in the past two weeks. It has hit some areas earlier — and harder — than others.
In one swath of the region that includes Pennsylvania, New York and New Jersey and has a population of about 41 million people, BA.2 as of Tuesday accounted from 51% of all new cases during the most recent two-week period. In the previous 14 days, it accounted for a little over 38%.
In the northeastern region comprised of Vermont, New Hampshire, Connecticut, Massachusetts, Rhode Island and Maine, which has a population close to 14 million, BA.2 has risen to 55% of all new cases, per the CDC.
Worldwide, BA.2 has long since achieved global domination, with the strain accounting for about 85% of all newly sequenced cases, per WHO.
The good news is that the Omicron strains (BA.2 and notably the original BA.1) are much less virulent than Delta, but as the U.S. saw in early February of this year, Omicron’s increased transmissibility can still create a wave of deaths equal to or surpassing that of Delta by the sheer number of infections alone. And BA.2 is thought to be 30% more transmissible that BA.1, which is why it is not outcompeting the original strain.
