US COVID levels decline as new subvariants rise steadily


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Center for Infectious Disease Research and Policy

Lisa Schnirring | News Editor | CIDRAP News

US COVID-19 indicators continue to slowly fall, but multiple new Omicron lineages are steadily cutting into the dominance of BA.5, the US Centers for Disease Control and Prevention (CDC) said today in its latest update.

In global developments, cases continue a steady rise in Europe, with the biggest impact on seniors.

Booster uptake sluggish amid falling cases

In a weekly review, the CDC today said the 7-day average for new daily COVID cases decreased 11.9% as of Oct 12 when compared to the previous week, with the country averaging 38,494 cases a day.

The 7-day average for new COVID hospitalizations decreased 4.4% over the same period. Deaths also declined, with the 7-day average for new daily COVID deaths down 8.5%. The country is now averaging 328 COVID deaths a day.

The percentage of counties with high community COVID levels declined slightly, and the number with medium community levels showed a moderate decrease, while counties with low community levels increased moderately.

More than 14.78 million Americans have received their updated bivalent booster, but the CDC emphasized that nearly half of the eligible population haven’t received any booster doses. In a related development, Pfizer and BioNTech yesterday announced phase 2/3 trial data that show that the new booster substantially increases BA.4/BA.5 neutralizing antibody response above prebooster levels, based on blood samples taken 7 days after vaccination.

Among the other metrics that the CDC tracks, the percentage of polymerase chain reaction (PCR) tests that were positive for COVID increased compared to the previous week, with the average 7-day positivity rate at 8.8%. And wastewater surveillance suggests that 35% of the country is reporting moderate to high SARS-CoV-2 levels.

BA.5 proportion shrinks

The BA.5 Omicron subvariant, first detected in South Africa in February, spread rapidly throughout the world and quickly became dominant, peaking in the United States in the middle of August. Since then—in both the United States and abroad—newer Omicron subvariants have been steadily gaining ground.

Some of the newer subvariants have mutations that allow them to evade earlier protection from infection or vaccination, adding uncertainty to how surges will evolve over the winter months.

In its latest variant proportion estimates today, the CDC said BA.5 slipped to 67.9%, with three others gaining steady ground: BQ.1 (5.7%), BQ.1.1 (5.7%), and BF.7 (5.3%). BA.4.6, which rose this summer, especially in the southern part of the Midwest, held relatively steady at 12.2%.

In other US developments, the Biden administration yesterday extended the public health emergency for the COVID-19 pandemic for another 90 days. The emergency has been in effect since Jan 21, 2020, and has now been renewed 11 times. Several response efforts hinge on the emergency declaration, which also allows the government more regulatory and funding flexibility.

Europe’s markers still tracking higher

In Europe, where COVID activity often precedes activity in other parts of the world, the region is seeing widespread increases in activity, especially in people ages 65 and older, with one third of countries reporting rising deaths, the European Centre for Disease Prevention and Control (ECDC) said today in a weekly snapshot.

Intensive care unit admissions continue to rise, and cases and deaths in nursing homes are increasing.

The group’s forecasts suggest the trend will continue for the next 2 weeks, and so far, there are no major changes in variant distribution.

In other global developments, Japan’s Fujifilm today announced that it has stopped development of the flu drug favipiravir (Avigan) for the treatment of COVID, due to a lack of significant benefit in phase 3 clinical trials. The study was designed to measure efficacy against severe symptoms in unvaccinated participants, but the company stopped enrollment after vaccination rates improved and Omicron, with lower symptom severity, became the dominant variant.