Wastewater, models point to latest crest of COVID wave

Sewage was a canary in the COVID-19 coal mine for Bay Area health officials. More than a month ago, they pointed to the sharp rise in virus levels detected in the sewage system as a harbinger of the omicron-fueled spike in cases. Sewage tests now show that virus levels are beginning to decline.

Along with modeling at the University of Washington that has proven to be accurate on the trajectory of the pandemic and experiences in other states and countries, this suggests that the omicron wave is peaking and is about to descend into Northern California and nationwide. It is a sign of hope for a public quite weary of the virus and all the restrictions it brings to their daily lives.

“We’re seeing some trends right now that suggest there might be a leveling off or even a downward trend,” said Michael Balliet, deputy director of the Santa Clara County Public Health Department, which oversees wastewater monitoring. in partnership with Stanford University.

Wastewater monitoring systems in other parts of the country are showing equally encouraging signs. The Massachusetts Water Resources Authority reported Tuesday that virus levels in Boston-area sewers had fallen to levels recorded on Dec. 30 — still higher than those seen before this winter, but nearly half of peak levels found the first week of January.

Alexandria Boehm, a professor of civil and environmental engineering at Stanford University who also monitors sewage virus levels for several other counties, including San Mateo, Modesto, San Francisco and Merced, said she’s seeing patterns peak similar to Sacramento.

Health experts expected, based on last winter’s experience and the trajectory of omicron outbreaks overseas, that this winter’s surge would peak and wane rapidly. In the UK, government data shows new daily COVID-19 cases fell to around 140,000 last week, after surging to over 200,000 earlier this month. Hospital admissions have also started to drop.

South Africa, where the omicron variant first appeared in November, has already seen cases peak and fall.

The influential model from the Institute for Health Metrics and Evaluation (IHME) at the University of Washington on January 8 predicts that the current wave of daily cases in the United States will reach approximately 1.2 million by January 19 and begin to fall about as fast as it rose – which was meteoric.

According to another IHME measure of estimated infections that include those unconfirmed and reported by testing, the latest US surge already peaked on Jan. 6 at 6.2 million. The daily U.S. hospital count is expected to peak on Jan. 25 at 273,000 and daily COVID-19 deaths on Jan. 24 at 1,930.

For California, the IHME model predicts daily cases will peak at 135,750 by January 24, with daily hospital counts reaching 31,510 by January 30 and daily COVID-19 deaths reaching 150 d here on February 1st. It already says estimated daily infections peaked on January 11 at 758,500.

The model will be updated again on Friday, but Ali Mokdad, science professor of health metrics at the University of Washington in Seattle, said he doesn’t expect the projections to change much.

California is experiencing a later peak than the rest of the country in part because the spread of the virus has been slowed by more widespread use of face masks and higher vaccination rates, stretching the tide, Mokdad said. But the University of Washington model predicts that more than half of the US population will have been infected with the omicron variant within the next six weeks. Mokdad said it was important for people to wear high-quality masks and have up-to-date vaccinations because omicron is so contagious and many of those infected show no symptoms.

The variant’s ability to infect people — even those who are vaccinated and masked — is evident in numbers compiled by the California Department of Public Health. California health data shows the seven-day average of daily cases hit 79,610 on Thursday, with 12,927 hospitalizations statewide and an average of 46 daily deaths from the virus. That’s up from 36,282 average daily cases, 8,671 statewide hospitalizations and 44 average daily deaths a week earlier.

But California Human Services Secretary Dr. Mark Ghaly was optimistic Wednesday that the current omicron attack will result in fewer hospitalizations and deaths than last winter’s COVID surge due to lower rates. the state’s high vaccination rates and the number of people recovered from a previous infection. The pandemic will enter a more manageable phase, he said.

“Our hope is that over the next few weeks…that our baseline immunity to the COVID-19 virus and its variants that we have seen before and those yet to come will be strong enough to prevent such an immense health spillover from people, of the health care delivery system, and we’re starting to move into a kind of new normal,” Ghaly said.

Hope that an end to the current outbreak is fast approaching is evident in the short-term nature of recently imposed restrictions, such as Sonoma County’s ban on large gatherings and universities like San Jose State. starting the new term with online courses, all of which are due to end within a month.

Yet, there remains some uncertainty. Boehm said that while the unprecedented levels of virus levels in Santa Clara County sewage over the past month have since “stabilized or, in some cases, decreased,” there is still reason to be concerned. worry:

“In previous surges, we stabilized a bit before the real downturn,” Boehm said. “We can’t be sure what the future holds for this push. New data is coming in daily, so we’ll be watching closely.

The Associated Press and NBC News contributed to this report.

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