‘Stealth omicron’ is in California and it may be in Sacramento. Here’s what we know

The coronavirus pandemic is in another bout of deja vu, as the World Health Organization warned people this week that a subvariant of omicron is spreading across the world.

Dubbed BA.2, the subvariant is not a “variant of concern,” the WHO said, but has been traveling in Denmark, India and the United Kingdom. And now it’s in California.

Santa Clara County health officials identified two cases of the subvariant, also known as “stealth omicron,” this week. There are 26 confirmed cases of BA.2 in California, as of Jan. 26, according to the California Department of Public Health.

It has also been detected in more than 40 countries, including Sweden, Singapore and the Philippines. It’s also in New Mexico, Texas and Washington, according to media reports.

Health officials are still investigating the transmissibility and severity of the virus, which is referred to as “stealth omicron,” the global health organization reported last week.

Where did BA.2 come from?

BA.2, which is rising in countries such as Denmark, India and the U.K., is a mutation of the omicron variant, according to the WHO.

“Every time that there’s transmission of the virus, that results in viral replication,” said Dr. Dean Blumberg, professor and chief of pediatric infectious disease at UC Davis Health. “It’s an opportunity for new mutations to occur.”

There are up to 32 mutations of the omicron COVID-19 variant, some of which have higher transmissability.

Will the subvariant spread as quickly as its predecessor?

Blumberg said it’s difficult to know, but there are concerns that it will spread very quickly. He cited the exponential growth in cases in Denmark, Israel and other countries where BA.2 is prevalent.

While the original omicron COVID variant accounts for 98% of global coronavirus cases, Reuters reported that BA.2 has become the most dominant viral strain in Denmark since the second week of January.

“The early data from Denmark suggests that it’s about 50% more transmissible than the original omicron strain,” Blumberg said.

Will the subvariant come to Sacramento?

Ultimately, it will come to Sacramento, if it is truly more transmissible, Blumberg said.

“These strains, if they’re anywhere in the world, eventually they’re going to be everywhere around the world, including in California,” he said.

He said he thinks that by the time the variant is detected and reported anywhere in California, it’s probably already here in the Sacramento area.

What mask do I need to wear to protect myself?

Health officials and the Centers for Disease Control and Prevention have recently issued recommendations that people upgrade their masks to N95s to increase protection from omicron.

“N95s are pretty much the best masks that are available for people these days,” Blumberg said, adding that they have 95% effective filtration.

“That’s higher than the 70% protection that we estimate that you get from the standard disposable surgical mask,” he said.

Blumberg recommends that people wear N95s if they are going to be in crowded areas with people outside of their household, especially if they are indoors. They are also helpful when people are doing activities where social distancing is difficult, such as riding in public transportation or traveling by plane.

I had COVID-19 already. Am I more immune to BA.2?

Not likely. Blumberg said that there are reports of people getting infected with BA.2 about a month after getting BA.1, the original omicron variant.

This suggests that the subvariant can evade previous immunity and that prior infection will not protect people from getting it, he said.

“With other strains, we know that reinfection is rare within 90 days of infection,” he said. “But it appears that that may not be true with B.A 2. The reinfection may occur earlier than that 90-day period.”

A medical expert said that it is unclear yet as to whether BA.2 will escape protection from vaccines or COVID medication, according to a USA Today report.

But health officials still urge vaccination and boosters, as it is the surest way to protect against severe infection.

“New variants will continue to evolve as long as there are large proportions of unvaccinated people,” according to the California Department of Public Health.

The longterm course of the subvariant is not yet clear. Health experts told USA Today it’s not time to panic.

How does BA.2 affect children?

Health officials are still investigating the severity of the subvariant.

Currently, Denmark is experiencing high rates of hospitalization of children ages 0 to 2.

“That’s something that we haven’t seen before,” Blumberg said. “And as a pediatrician, that’s very concerning to me, and I think we need to follow that very closely to see if children somehow are more predisposed to more frequent infection or more severe infection.”

This story was originally published January 28, 2022 at 5:15 AM.