Highly contagious delta variant now the most dominant version of virus in California
The more contagious coronavirus variant called delta is now the most common version of the virus in California, state data shows.
Nearly 36% of coronavirus samples sequenced in June comprise the delta variant, according to the California Department of Public Health. In May, the delta variant made up just 5.6% of sequenced cases in the state.
As of June 30, 63,447 samples have been sequenced in California.
The delta variant, which was first identified in India, has surpassed the previously dominant alpha variant that first emerged from the U.K. About 34% of sequenced coronavirus cases in June are of the alpha variant. The next most common variant in California is gamma, which was first identified in Japan/Brazil.
“What’s surprising to me is not only that it’s the most common, but the rate of increase is really dizzying,” Dr. Peter Chin-Hong, an infectious disease expert at the University of California, San Francisco, told NBC. “It’s expected to be over 90% in a few months, if not in a few weeks.”
Emerging evidence shows the delta variant is more contagious, increases disease severity such as risks of hospitalization and is associated with a “modest” decrease in antibody activity in previously infected and vaccinated people compared to the alpha variant.
The most recent data suggests it’s about 60% more contagious than the alpha variant.
“The fact that [the delta variant] produces more virus and people produce virus for a longer period of time, not only makes it more transmissible but potentially more deadly,” Chin-Hong told NBC.
However, studies show the COVID-19 vaccines offer adequate protection against the delta variant and other variants of concern in the U.S. Experts are more concerned about the unvaccinated people who face higher risks of infection.
Director of the Centers for Disease Control and Prevention Dr. Rochelle Walensky said during a White House COVID-19 briefing Thursday that the delta variant makes up about 25% of sequenced coronavirus cases nationwide. And in some regions, “nearly” half of analyzed cases comprise the delta variant.
In California, the number of people hospitalized for COVID-19 dropped to 915 on June 12 — “the lowest it has been since the state began tracking cases,” the Los Angeles Times reported. By July 3, “there were 1,097 COVID-19 patients in hospitals statewide, a 20% increase.”
“We know our hospitalizations are creeping up — and most of the patients are unvaccinated,” Gov. Gavin Newsom tweeted Friday. “We also know the science is clear — getting vaccinated protects you AND those around you. Get vaccinated.”
The World Health Organization suggested fully vaccinated people still wear face masks whenever possible, citing the delta variant’s increased transmissibility and risk of serious COVID-19 across the globe.
The advice arrived more than a month after the CDC gave the green light for fully vaccinated Americans to ditch their masks in most scenarios. But in response to the WHO’s advice, Walensky said “if you are vaccinated, you are safe from the variants that are circulating here in the United States.”
The CDC said it will leave decisions on face mask requirements up to individual states.
California’s mask requirements follow those of the CDC, which state vaccinated people don’t have to wear face coverings except while on public transportation or in health care settings, schools, detention centers or homeless/emergency shelters. Unvaccinated people must still wear masks in all indoor scenarios.
The Los Angeles County Department of Public Health recently recommended residents wear masks while in public indoor spaces, regardless of vaccination status. It was the first local precaution in the U.S. spurred by concerns over the delta variant.
Many health experts outside the CDC and WHO seem to agree with erring on the side of caution.
This story was originally published July 6, 2021 at 2:03 PM.
