Mutant coronavirus variants are a growing threat. Vaccinations, mask wearing are essential

While emerging coronavirus variants remain a threat, health experts said they are hopeful that rising vaccination rates and continued wearing of masks can blunt the potential for a new wave.

There are indeed concerns about whether the immunity offered by vaccines will be less effective against some coronavirus variants, including the strain first identified in South Africa, B.1.351, and the homegrown California strain, B.1.427/B.1.429.

Researchers at UC San Francisco said that in lab tests, the California strain was more resistant to the effects of neutralizing antibodies that are generated by the immune system in response to COVID-19 vaccines or by a previous coronavirus infection. Compared with other variants, the protection provided by the antibodies was reduced by a “moderate ... but significant” amount, the UCSF researchers said.

When the neutralizing antibodies went up against the homegrown strain, their effectiveness was cut in half. By comparison, when these antibodies encountered the coronavirus strain that’s now dominant in South Africa, their effectiveness was reduced to one-sixth of their usual levels.

Vaccine makers have begun working on booster shots that would be a better match for the new variants. But researchers say that the vaccines are still quite good and remain our best bet for being protected against the virus. Doctors urge people to get the shots as soon as they’re eligible.

The vaccination campaigns are an important contributor to the continuing decline in daily coronavirus cases, and that trend is gratifying, Dr. Eric McDonald, medical director of the San Diego County epidemiology department, said this week.

McDonald said that even if the California strain “is a little more contagious than the other ones that are circulating in the community, the take-home message is the same: that you need to do all the things that we’ve recommended to prevent transmission — so, wearing masks, social distancing, staying at home.”

“We couldn’t say it in stronger terms: We think it is a mistake to take our foot off the gas too early, especially when we are accelerating our vaccination efforts right now,” said Andy Slavitt, senior advisor to the White House COVID-19 Response Team.

Vaccinations have been a factor in the decline of new coronavirus cases in L.A. County, along with the fact that so many residents have developed some immunity through exposure to the virus. Health officials also credit residents’ greater adherence to guidelines about wearing masks in public and avoiding social gatherings since the autumn-and-winter surge began. (Officials have also not detected a surge in cases related to gatherings over the Super Bowl weekend.)

In L.A. County’s skilled nursing facilities — among the first places where vaccines were administered — new daily coronavirus cases have plummeted in the last few weeks, Public Health Director Barbara Ferrer said this week. As of Feb. 7, the average number of daily coronavirus cases associated with residents in skilled nursing facilities was just five. Four weeks earlier, that number was more than 100.

As of Feb. 14, 74% of residents eligible for shots at skilled nursing facilities in L.A. County, and 77% of staff, had received their first dose of the COVID-19 vaccine. Of those who’ve had their first dose, 83% of staff and 79% of residents have received their second shot as well.

“With many more staff and residents vaccinated, new cases should continue to decline, which does mean less outbreaks, and fortunately, less deaths,” Ferrer said.

Dr. Anthony Fauci, the U.S. government’s top infectious diseases expert, said the rise of the variants made it all the more essential that people get vaccinated as soon as they can.

Fauci has raised the concern that a survival-of-the-fittest contest between the U.K. and California variants could accelerate the spread of the strain that’s best able to elude the effects of COVID-19 vaccines. The best way to prevent this, Fauci told The Times, is to stop the spread of both variants by getting vaccinated, wearing masks and limiting exposure to others.

New daily cases have been falling dramatically in California, but the week-over-week decline has softened in recent days. As of Thursday, California was averaging about 5,800 cases a day, a 21% decline from a week earlier. The previous week-over-week decline was greater, 34%.

Federal officials expressed worry Friday that the decline in national daily coronavirus cases is starting to flatten, as one of the mutant variants, from the U.K., is increasing throughout the nation.

They warned against states relaxing COVID-19 restrictions, saying the nation remains at a precarious point that could tip into a fourth surge before more people get vaccinated.

“We are at that very precarious position that we were right before the fall surge — where anything that could perturb that could give us another surge,” Fauci told reporters at a briefing Friday. “We don’t want to be people always looking at the dark side of things, but you want to be realistic. So we have to carefully look at what happens over the next week or so with those numbers before you start making the understandable [decisions] to relax on certain restrictions.”

California’s average daily number of coronavirus cases is at its lowest point since the autumn-and-winter surge began its rapid acceleration in early November. The statewide daily case number has fallen 87% since early January, when there were 45,000 new cases per day.

California’s COVID-19 hospitalizations have dropped by 75% from their Jan. 6 peak of 21,936; that number had fallen to 5,590 as of Thursday, the lowest since Nov. 23.

In addition, the number of people with COVID-19 in California’s intensive care units is down 66%, falling from a peak of 4,868 on Jan. 10 to 1,640 on Thursday. That’s the lowest such number since Nov. 28.

The rate at which coronavirus test results are coming back positive over the last seven days hit 2.7% Friday, a substantial decline from the peak of the winter surge, when the positivity rate topped out at 14.34% for the seven-day period that ended Jan 7. California’s positivity rate is now the lowest it has been since mid-October.

Hundreds of COVID-19 deaths are still being reported daily, although at a lower rate than the peak of about 562 deaths a day in late January. On Thursday, 401 additional COVID-19 deaths were reported by California’s 61 local health agencies, according to a Times tally; an additional 395 deaths were reported by Friday evening, according to an incomplete early survey.

By Friday evening, California’s local health agencies had reported a total of 51,788 COVID-19 deaths in the state since the pandemic began. On a per capita basis, California has the 30th-highest cumulative COVID-19 death rate among the 50 states and the District of Columbia.