The rapidly spreading omicron variant of COVID-19 has come to dominate the highly contagious delta form across much of the United States, rising from less than 13% of sequenced cases on December 11 to over 73% in a week, the Centers for Disease Control and Prevention said Monday.
It was unclear how quickly the omicron spread in California – the California Department of Public Health did not update its variant tracking data and did not provide immediate comment on Monday. But the virus’s rapid spread across the rest of the country has alarmed infectious disease specialists.
“Surprisingly – faster than I expected,” said Dr. John Schwarzberg, emeritus clinical professor of infectious disease and vaccinology at the School of Public Health at the University of California, Berkeley. “I think it’s fair to say it’s explosive.”
In the Bay Area, where the first case of omicron variant was reported in the United States on December 1 in a vaccinated San Francisco resident who recently returned from South Africa, and two days later, six cases in Alameda County and one case in Santa Clara County per week. later, health officials prepared for a spike in infections and urged residents to revaccinate.
Contra Costa County reported its first cases of this option on Monday – three residents, two of whom were fully vaccinated, although none of them had yet received a booster shot. So far, no one has been hospitalized.
“We knew it was only a matter of time before the omicron variant would appear in Contra Costa County,” District Nurses Dr. Chris Farnitano said in a statement. “We encourage everyone eligible to receive a booster dose of Pfizer or Moderna vaccine to do so. Today’s news and holidays are just around the corner, this is even more important. People who get boosted are much less likely to get seriously ill or be hospitalized. This is our wish for this holiday season. “
The rapid spread of Omkron in South Africa last month alarmed health officials around the world, prompting the World Health Organization to declare the Omicron a “worrying option” on November 26. On Monday, the WHO director-general urged people to cancel holiday gatherings to slow it down.
“There is now strong evidence that the omicron is spreading significantly faster than the delta variant,” said CEO Tedros Adhanom Ghebreyesus. “There can be little doubt that wider social mixing during the holidays in many countries will lead to more cases, overwhelmed health systems and more deaths. … Better to cancel now and celebrate later than celebrate now and grieve later. “
CDC Director Dr Rochelle Walenski said on December 14 that the omicron variant was “around 3% nationwide” and “growing rapidly”, gaining momentum against the highly hereditary delta variant that has dominated since June and caused outbreaks across the country. USA in summer and autumn. Since then, the agency has revised its figures for the week of December 11 upward to 12.6%. This variant has spread most rapidly in New York and other states on the East Coast, Midwest, Great Lakes, and Northwest regions.
CDC data show that the omicron variant ranges from 0.7% of cases in the US on December 4 to 12.6% by December 11 and 73.2% by December 18. It took Delta more than a month to reach this level of dominance across the country.
California Department of Health data show that the delta variant began to gain traction in April. Two months later, delta was less than half of the sequenced samples. But just a month after that, in July, delta accounted for 93% of cases, peaking at 99.5% last month. As of Dec 15, delta was 98.6% and omicron was 49 cases, 1.4% of samples sequenced in the state.
Schwarzberg said the omicron turns out to be about five times more transferable than the delta variant, which itself was more transferable than previous variants, and that it is “difficult to imagine” its trajectory in California, unlike its rapid growth nationwide. …
Health experts across the country have called on people to get boosted to boost their immunity. Earlier this month, the CDC authorized boosters for everyone aged 16 and over.
Dr. Ashish Q. Jha, Dean of the School of Public Health at Brown University, said on Twitter Monday that “the omicron is practically everywhere now.”
“It became dominant so quickly,” Jha said. “Bring you an accelerator. Wear the mask to large indoor events. Use rapid tests before collection. We can handle this, people. “
Much remains to be seen about how virulent the omicron variant will prove to be, with some data and reports suggesting milder illness and transient spikes in infection.
Dr. George Rutherford, an infectious disease specialist at the University of California, San Francisco, said the UK data suggests relatively few omicron hospitalizations and deaths at this time. If the new variant causes milder disease, he said, seeing it outperform the lethal delta variant would be a blessing.
Rutherford also noted that data from overseas suggest a short-term spike in the number of cases before the wave of omicronic infection begins to hit, which would also be merciful.
Schwarzberg said a recent study in Hong Kong found that while omicron infects the upper respiratory tract more easily, it is less active in the lower respiratory tract, which can lead to more serious illness.
“Upper respiratory tract disease is a cold, we can live with it,” Schwarzberg said. But he added that he was “challenging” a recent study from Imperial College London that found the omicron was just as dangerous as the delta. “So we’ll have to wait and see.”