Concerns about the new California coronavirus mutant increase as the country records 500,000 deaths.

However, variants that are more infectious and have other anxious traits are severe reminders to maintain behavior to prevent the spread of the disease, such as wearing facial coverings and avoiding gatherings. Must be. Public health officials also say they are closely monitoring variants that could cause new outbreaks and delay plans to restart the economy, including versions grown in California.

“Is there a local outbreak or a superspreading event? Is it more likely as we open? We still don’t know,” a team from the University of California, San Francisco said in a preliminary survey on Monday. Dr. Charles Chiu, who published the results, said it suggests that California variants are more infectious. A variant identified in the United Kingdom “really slowed the opening in the United Kingdom. If this turns out to be similarly infectious, the same could have to happen in the United States.”

The British variant, known as B.1.1.7, is about 50% more infectious than the version of the coronavirus that dominated most of the pandemic. According to the Centers for Disease Control and Prevention, the variant has been identified in 44 states, including California. The CDC estimates that it could become the predominant variant in some parts of the country by March.

However, the California variant seems to offer some competition. Although 90% of cases occur in California, they are currently documented in 45 states, Chiu said. By the end of January, this variant accounted for more than half of the cases analyzed by the UCSF Chiu team, which examined 44 data out of 58 California counties, including all nine Bay Area counties. As in September last year, this subspecies was rare, accounting for less than 1% of cases.

“This variant should probably be treated with the same level of concern as these other variants,” Chiu said.

He believes that California variants need to be added to the global list of “subspecies of concern” monitored by several health organizations. The CDC closely monitors three variants: the United Kingdom, South Africa and Brazil.

Infectious disease experts independently identified in January that two teams of scientists, Chiu from the University of California, San Francisco and another group in Los Angeles, are rapidly prevailing in several communities, including the Bay Area. At times, I was concerned about California variants. This variant was found to be responsible for the outbreak that infected more than 90 people in San Jose’s Kaiser Permanente.

The dramatic increase in variants in a short period of time, which was associated with several outbreaks, caused an early warning signal that could spread more easily. However, two studies published on Monday provided the first solid evidence that the variants were more infectious. Neither study has been published.

Based on an analysis of several nursing home clusters, Chiu’s team found that variants seemed to spread faster in outbreaks. In addition, the virus was more concentrated in samples taken from individuals infected with the variant. Both are signs of increased infectivity. Scientists have also found in laboratory studies that this variant is more infectious.

Meanwhile, scientists at Chan Zuckerberg Biohub and UCSF have found in a study of more than 630 cases in the mission area that this variant spreads more easily at home. The team found that about 35% of household members were infected when one of the California variants was brought home. The attack rate of other variants was about 26%.

“We don’t want to be vigilant,” said Joe DeRisi, co-president of Biohub, on the findings of the mission district. “But it highlights the need to examine this strain more carefully and do more research on it. We need to recognize that it is in the community and is spreading rapidly.”

The mission district study was coordinated by Chan Zuckerberg Biohub, UCSF, the San Francisco Public Health Service, and Unidos en Salud, a collaboration of the Latin American Task Force of COVID-19.

Chiu’s team has also shown that this variant is associated with worse results for COVID-19, suggesting that it may be more toxic. Patients infected with the mutant were more likely to be ventilated, treated in the intensive care unit, or die. However, Chiu said the number of hospitalized cases examined by his team was relatively small and further research is needed to ensure that the mutation causes more serious illness.

The team also examined the immune response evoked by a vaccinated person or a person previously infected with the coronavirus against the mutant. The mutant was resistant to several antibodies in both groups. This indicates that the vaccine can be somewhat weakened and people can be prone to reinfecting the mutant.

Chiu said he believed the vaccine would continue to be effective. “The overall vaccine response is very strong,” he said.