CDC foresees spread in U.S. of highly contagious coronavirus variant

The cases have been mostly isolated: One in New York, one in Florida, one in Georgia and two in Colorado. The exception has been California, and specifically San Diego County, where a robust surveillance operation has found 32 cases of the variant. National Institutes of Health Director Francis Collins told The Washington Post on Wednesday: “I would be surprised if that doesn’t grow pretty rapidly.”

There is no evidence that the variant, which has recently been detected in more than 30 countries, carries a greater risk of severe disease or death. But the appearance of coronavirus variants, including another mutation-laden variant that has shown up in South Africa, presents a challenge for every country hoping to crush the pandemic.

A more transmissible virus could drive more patients into hospitals and boost the covid-19 death toll. It also could prolong the march toward herd immunity. That’s the point at which a pathogen circulating through a population will slam into so many people with immunity that any outbreak quickly dies out and doesn’t turn into an epidemic. The percentage of people who need to be immune for a population to achieve herd immunity is higher for more infectious pathogens.

The rise of variants also could limit the efficacy of monoclonal antibody treatments because such therapeutics are very narrowly focused and potentially could be eluded by a single mutation.

The implications for vaccines are fuzzy over the long term because the coronavirus will keep mutating. But the consensus is that the newly authorized vaccines are likely to remain effective against any variants seen so far because they elicit a broad array of neutralizing antibodies and other immune system responses. Moreover, the mRNA (messenger RNA) vaccines from Pfizer/BioNTech and Moderna can be readily tweaked if necessary in response to mutations.

All of this argues for increased surveillance of the virus as it spreads through the population and collides with natural and vaccine-induced immunity. The virus is not static, and although the mutations are random, natural selection will lead to variants that are more capable of infecting and replicating in human beings. A study published last week by scientists at Imperial College London, and not yet peer-reviewed, estimated that the variant first detected in Britain is 50 percent more transmissible than the more common strain of the virus.

“Here at the CDC, we’re definitely taking this seriously, and we’re assuming for now that this variant is more transmissible,” said Greg Armstrong, the leader of the strain surveillance program at the CDC, which is still ramping up. The British variant “is probably not in every state at this point, but I think in a lot of states.”

Experts say this heightens the urgency of vaccinating as many people as possible, and some respected scientists have argued that the protocol for distributing two-dose vaccines should be altered to get more people inoculated, even if that means cutting doses in half or delaying the second dose. The Food and Drug Administration this week said it would stick with the two-shot dose backed by randomized clinical trials.

All viruses mutate, and SARS-C0V-2, the novel coronavirus, doesn’t mutate quickly or in any unusual way. But with tens of millions of people infected around the world, the virus has had abundant opportunity to shape-shift randomly, and natural selection does the rest, potentially giving the virus the ability to evade natural or vaccine-induced immunity.

“We are in a race against time,” said Jennifer Nuzzo, an epidemiologist with the Johns Hopkins Center for Health Security. “We need to increase our speed in which we act so that we don’t allow this virus to spread further and allow this variant to become the dominant one in circulation. The clock is ticking.”

The United States has been slow to develop the kind of genomic sequencing that has enabled Britain to closely monitor mutations in the virus and the spread of different variants. The CDC established a consortium last spring to collect data on genomic sequences and in November created the new program in strain surveillance.

Armstrong said in an interview that in the next two weeks, the agency and its contracted partners hope to more than double the number of genomic sequences posted on public websites.

“We’re not sequencing enough yet, and we need to continue to build what we’re doing,” Armstrong said.

The South African variant hasn’t been detected in the United States, he said. But the British variant may have been here since October, according to preliminary data from private coronavirus tests. That data is not fully conclusive because it is not based on comprehensive genomic sequencing.

Instead, the British variant is missing a portion of the genetic code seen in the common coronavirus. By chance, the commonly used Thermo Fisher PCR test can detect that dropped gene in positive test results. Other variants that…