Here’s everything you need to know

This transmission electron microscope image shows SARS-CoV-2—also known as 2019-nCoV, the virus that causes COVID-19. isolated from a patient in the U.S., emerging from the surface of cells cultured in the lab.

Source: NIAID-RML

Even as global Covid-19 infections drop across the world, leading U.S. health officials are warning of a coming wave of infections as new, more contagious — and possibly more deadly — variants of the virus take hold in the U.S.

Scientists aren’t surprised by the emergence of the new variants and have reiterated that the currently available vaccines should still work against them — albeit, a bit less effective than as against the original, “wild” strain. However, top U.S. health officials and infectious disease experts worry that these highly contagious variants, particularly the B.1.1.7 strain that emerged in the U.K, could reverse the current downward trajectory in infections in the U.S. and delay the country’s recovery from the pandemic.

“I think we should be assuming that the next wave of case growth, to the extent that we have it, is going to be with B.1.1.7, and that’s something that I think everybody has to be even more cautious about,” Andy Slavitt, White House Covid-19 senior adviser, told MSNBC last week. “It’s nice to see the numbers of cases drop, but it could be misleading.” 

Why viruses mutate

“You can think of it as trying out new solutions,” Lauring said. “Either that mutation is going to make you a better virus or a worse virus, and then what you have is selection. Survival of the fittest, for the lack of a better term.”

Research shows that more worrisome virus mutations could be coming from people who are immunocompromised since it takes their body longer to respond and clear the virus, giving it more time to figure us out and mutate, said Dr. Dennis Burton, the Scripps Research Institute Chair of Immunology and Microbiology.

“If somebody has the virus, and they clear it in a couple of days, you’ve not got much chance to mutate,” Burton told CNBC in a phone interview. “But if somebody has the virus like an immunocompromised person, and they harbor the virus for weeks, then it’s going to have a lot more chance to mutate.”

Why are some worse than others

Only a small number of variants become a public health concern, infectious disease experts say. Those variants typically become easier to spread, cause more severe illness in people who are infected, or evade some of the protections from vaccines and antibodies.

CDC Director Dr. Rochelle Walensky told JAMA on Wednesday that the B.1.1.7 variant is thought to be roughly 50% more transmissible and early data indicates it could be up to 50% more virulent, or deadly.

There’s also evidence to suggest that people infected with earlier strains of the virus could be reinfected with the B.1.351 variant found in South Africa, Walensky wrote in a JAMA viewpoint with White House Chief Medical Advisor Dr. Anthony Fauci and Dr. Henry Walke, the CDC’s Covid incident manager.

SARS-CoV-2 is a coronavirus, which is a large family of viruses named “for the crown-like spikes on their surfaces,” according to the CDC. Researchers monitor those spikes, or the S-protein, for mutations because they can allow the virus to bind to cells easier or increase the amount of virus a person sheds.

The S-protein has what’s called a “receptor binding domain” that acts like the “the hand of the spike” that grabs hold of what’s known as an ACE2 receptor on human cells, Dr. Daniel Griffin, chief of infectious diseases for ProHEALTH, told CNBC.

Changes to the S-protein could be a problem because those spikes have been the target of neutralizing antibodies that fight Covid-19 and are created through natural infection or vaccination, Griffin said. They could also impact the performance of monoclonal antibody therapies that prevent people from developing severe illness.

For instance, the B.1.1.7 variant first identified in the U.K. has several different mutations, according to the CDC. One of the key mutations, N501Y, is a change in the spike protein that scientists think help the virus bind to cells easier.

The same key N501Y mutation has separately developed in the B.1.351 variant identified in South Africa and the P.1 variant in Brazil. Both strains have also developed another concerning mutation in their spike proteins, known as E484K.

The CDC warns that this mutation, which has now been identified in some B.1.1.7 cases, could be resistant to antibody drug therapies, and early studies show that it may reduce the effectiveness of some vaccines.

“This is the one that actually gets me concerned,” Griffin told CNBC, referring to the E484K mutation.

What this means for vaccines

Pfizer and Moderna

Finding the mutations

The CDC has partnered with public health and commercial laboratories to rapidly scale up the nation’s genomic sequencing. Walensky told JAMA Wednesday that in January, the U.S. was only sequencing 250 samples per week in, which has since grown “to the thousands.” She added that “we’re not where we need to be.”

Dr. Ilhem Messaoudi, the director of the University of California at Irvine’s Center for Virus Research, said the process can be time consuming and labor intensive, but emerging strains will be missed if laboratories aren’t sequencing a certain percentage of all positive Covid-19 test results to find the new mutations, she said.

“Now we’re trying to catch up,” Messaoudi said in a phone interview with CNBC. “We’re like, ‘Let’s go back and see if we have this.'”

Masks, social distancing

The rapidly spreading variants renew the importance of suppressing the coronavirus’ spread through public health measures, like wearing masks, social distancing and hand hygiene, to prevent further mutations and buy time for countries to deploy life-saving vaccines.

But coronavirus variants aren’t just a problem for the United States. If the virus circulates in other parts of the world that are unvaccinated, it could lead to mutations that may threaten the widely deployed vaccines in other countries, the head of the CDC warned on Wednesday.

Eventually, the whole world will need to build an immunity to the virus, or else the variants will continue to be a problem, Burton told CNBC.

“Sooner or later variants will get everywhere if they’ve got a big advantage” Burton said. “It’s a global problem, it’s not just a problem for any one country.”

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