Even though California continues to see major drops in COVID-19 after the recent holiday boom, there is growing concern about another potential problem to come.
New research strongly suggests that the now dominant coronavirus strain in California not only spreads more readily than its predecessors, but also has the ability to prevent antibodies generated by COVID-19 vaccines or previous infection. It is also associated with more serious illness and death.
These attributes left some scientists concerned that the local variant could reverse the state’s recent progress in reducing new infections – especially if it is able to exchange mutations with other threatening strains. Experts say this reinforces the need to vaccinate people as soon as possible and to continue wearing masks, maintaining social distance and following other public health care as the state begins to reopen more.
Five counties are now eligible to open internal operations in dining rooms of restaurants, gyms, cinemas, museums, zoos and aquariums amid a dramatic improvement in the COVID-19 pandemic, Governor Gavin Newsom said Tuesday. Other counties are likely to follow suit soon if cases continue to fall.
Many pandemic indicators continue to improve dramatically. California is now recording about 6,000 new cases of coronavirus daily, below 45,000 a day from six weeks ago. The number of COVID-19 patients in California hospitals on Sunday was 6,569, down from an increase of 21,936 on January 6.
Could the California strain undo this progress? Here is what we know about the variant that probably appeared in the state in May:
Is California tension important?
California, along with the rest of the country, has been preparing for an attack on one most transmissible strain of the United Kingdom known as B.1.1.7. But the California strain is probably just as worrying and has already established itself. At the end of next month, the home grown strain – known by scientists as B.1.427 / B.1.429 – will likely account for 90% of the state’s coronavirus infections, he said. Dr. Charles Chiu, infectious disease researcher and physician at UC San Francisco.
Samples collected in several counties using a variety of methods suggest that the variant is 19% to 24% more transmissible.
Chiu and his UCSF colleagues say the cluster of mutations that characterizes the home grown strain it should mark it as a “concern variant” at the same level as those in the UK, South Africa and Brazil.
What makes scientists think it is more transmissible?
The researchers saw uniform patterns in how the variant spread across the state’s counties. And when coronavirus infection rates increased across the state, they usually did so alongside growing evidence of the presence of the California strain.
There is also evidence of laboratory tests. An analysis of viral samples from across the state showed that, compared to people infected with other strains of SARS-CoV-2, those who were infected with the California strain had viral loads twice as high in the nasopharynx. This made it very likely that each person infected with the new strain would spread more people.
The B.1.427 / B.1.429 genome includes three mutations that affect the virus’s spike protein, which it uses to infiltrate human cells and convert them into factories for their own reproduction. One of these three mutations, dubbed L452R, affects the so-called receptor-binding domain, helping the virus to attach itself more firmly to target cells.
Is it dangerous in other ways?
The L452R mutations appear to make the California strain more harmful to the body as well.
A coronavirus designed to have only this mutation was able to infect human lung tissue at least 40% more readily than other circulating variants that did not have the mutation. Compared to so-called wild-type strains, the modified virus was also more than three times more infectious.
Dr. Bruce Walker, an immunologist and founding director of the Ragon Institute in Boston, said that while viruses often mutate to make them stronger, these genetic changes often impose a new Achilles’ heel. For example, a strain that spreads more easily usually loses some of its virulence.
The worrying thing about the California variant, said Walker, is that no apparent weaknesses have been introduced alongside mutations that add additional strength.
How does it behave against the COVID-19 vaccines?
In the laboratory, the California strain was more resistant to neutralizing antibodies that are generated in response to COVID-19 vaccines or a previous infection with coronavirus. Compared to existing variants, the reduction in protection was “moderate … but significant,” said UCSF researchers.
When neutralizing antibodies increased against the home grown strain, its effectiveness was halved. In comparison, when these antibodies found the coronavirus strain that is now dominant in South Africa, its effectiveness has been reduced to one sixth of its usual levels.
“I predict that over time this will have an effect on vaccination,” said Chiu. Although the magnitude of the effect varied from sample to sample and was less pronounced than with the South African strain, “it is still worrying,” he said.
Is this tension to blame for the increase in the state holiday?
Not entirely, but he was probably one of the many contributors to the rise that hit the state during the fall and early winter.
In northern California, at least, new infections have already started to increase dramatically by the time the new variant announced its presence, said Chiu. Across Southern California, the overlap was narrower.
What is the ‘nightmare scenario’ with this variant?
The UK and California variants are equipped with improved capabilities, and the likelihood that they can circulate in the same population increases the spectrum of a return to increased infections and deaths, said Chiu. It also opens the door to the possibility that the two viruses meet in a single person, exchange their mutations and create an even more dangerous strain of the SARS-CoV-2 virus.
Chiu called this a “nightmare scenario”.
Dr. Anthony Fauci, the country’s leading infectious disease specialist, raised another concern: a competition for the survival of the fittest between the UK and California variants could accelerate the spread of the strain that is best able to prevent the effects of the COVID-19 vaccines, he said . The best way to prevent this, he added, is to prevent the spread of any of the variants by getting vaccinated, wearing masks and limiting exposure to other people.