Coronavirus US: are current vaccines effective against the Californian strain?

Covid-19 variants coming from the UK, Brazil and South Africa have been getting all the attention while there has been a concerning strain quietly developing and spreading on home soil, in California.

The new variant, which scientists refer to as B.1.427/B.1.429, which came on the radar in September 2020 is thought to spread more quickly than others. According to a limited but worrying new study there are now concerns that it could be better at dodging antibodies created by previous infection or a vaccine, and may cause more serious illness.

How worrying is the new strain and will the vaccines work against the Californian variant?

Do vaccines protect against California's covid strain?

It's still too early to say for sure whether the Golden State strain will evade vaccines, scientists are still monitoring the situation closely. But back in January, Dr. Charles Chiu, a virologist and professor of laboratory medicine at University of California, San Francisco said that there’s concern about the covid-19 vaccine’s efficacy against the variant. “The data is preliminary, but it basically does raise the concern that there may be some impact on the vaccine.”

As we reported previously, with regards to the covid variant discovered in the UK research didn't show cause for concern that the vaccines could be evaded by the new mutation.

In addition, both Pfizer and Moderna have carried out early lab tests on the efficacy of their existing vaccines on the new UK and South African variants. Both companies found that their current vaccines are almost equally as effective on the new UK strain as they are against earlier variants upon which they were developed. However, both vaccines were found to offer slightly less protection against the South African variant.

On Friday, a Johnson & Johnson single shot vaccine was recommended by the FDA advisory panel, paving the way for the latest vaccine success story to be granted emergency use authorisation next week, little is known about how this vaccine would fare against the variant discovered in the Golden State but it's another shot at success.

Covid-19: thousands of unremarkable mutations

Virus mutations in general are nothing unusual or particularly concerning. Most viruses mutate quickly, accumulating changes in their biology as they replicate. Copying genetic code perfectly is hard and when you multiply as many times as a virus does, you pick up a lot of errors also known as mutations.

Those mutations allow viruses to adapt quickly to changes in their host environment. Most mutations actually scupper a virus’ effectiveness in making us sick, some are neutral and others will even help it spread.

By July 2020 over 12,000 mutant versions of covid-19 had been identified, according to the New Scientist, though there will be tens of thousands more versions that differ by just a single mutation. Overall any two covid-19 coronaviruses (SARS-CoV-2) will only differ by fewer than 30 mutations and are considered as belonging to the same strain.

What’s causing the alarm over the California variant?

“This variant is concerning because our data shows that it is more contagious, more likely to be associated with severe illness, and at least partially resistant to neutralizing antibodies,” says Charles Chiu, an infectious diseases physician and sequencing expert at University of California, San Francisco (UCSF) who is the senior author of a preprint reporting lab studies and epidemiological data.

The data suggest the new strain “should likely be designated a variant of concern warranting urgent follow-up investigation,” the authors write in their preprint, which has not been peer reviewed and which they say is expected to be posted online soon. "The devil is already here" Chiu told the LA Times.

In other words, there is limited proof that the new strain found in California is more resistant to antibodies and more likely to cause serious illness or fatalities.

On the subject of vaccine efficacy, Chiu went on to tell the Times that "if we can get enough people vaccinated, we will be able to deal with these variants simply because we won't have ongoing transmission."

The same mitigation measures apply to new variants as the original coronavirus strain: wear a mask, socially distance and do not spend time indoors with people outside of your household.

Other scientists more cautious on California strain

However, Science Mag this week reported that other coronavirus experts say more data is needed before real conclusions are drawn, noting that among patients with the variant, the study included fewer than 10 who were admitted to the ICU and fewer than 10 who died.

“If I were a reviewer, I would want to see more data from more infected people to substantiate this very provocative claim,” says David O’Connor, a viral sequencing expert at the University of Wisconsin, Madison, who was not part of the research.

"I'm increasingly convinced that this one is transmitting more than others locally," William Hanage, an epidemiologist at the Harvard T.H. Chan School of Public Health who was not involved in the research, told The New York Times, with reference to the highly contagious variant found in the UK Hanage added "But there's not evidence to suggest that it's in the same ballpark as B.1.1.7."

For their study, the authors sequenced 2172 genomes from virus samples captured from 300 patients in 44 California counties between 1 September 2020 and 29 January 2021.