What We Know and Don't Know About Virus Variants and Vaccines

Damian McNamara

January 21, 2021

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About 20 states across the country have detected the more transmissible B.1.1.7 SARS-CoV-2 variant to date. Given the unknowns of the emerging situation, experts with the Infectious Diseases Society of America (IDSA) addressed vaccine effectiveness, how well equipped the United States is to track new mutations, and shared their impressions of President Joe Biden's COVID-19 executive orders.

Dr Mirella Salvatore

One of the major concerns remains the ability of COVID-19 vaccines to work on new strains. "All of our vaccines target the spike protein and try to elicit neutralizing antibodies that bind to that protein," Mirella Salvatore, MD, assistant professor of medicine and population health sciences at Weill Cornell Medicine in New York City, said during an IDSA press briefing on Thursday.

The B.1.1.7 mutation occurs in the "very important" spike protein, a component of the SARS-CoV-2 virus necessary for binding, which allows the virus to enter cells, added Salvatore, an IDSA fellow.

The evidence suggests that SARS-CoV-2 should be capable of producing one or two mutations per month. However, the B.1.1.7 variant surprised investigators in the United Kingdom when they first discovered the strain had 17 mutations, Salvatore said.

It's still unknown why this particular strain is more transmissible, but Salvatore speculated that the mutation gives the virus an advantage and increases binding, allowing it to enter cells more easily. She added that the mutations might have arisen among immunocompromised people infected with SARS-CoV-2, but "that is just a hypothesis."

Dr Kathryn Edwards

On a positive note, Kathryn M. Edwards, MD, another IDSA fellow, explained at the briefing that the existing vaccines target more than one location on the virus' spike protein. Therefore, "if there is a mutation that changes one structure of the spike protein, there will be other areas where the binding can occur."

This polyclonal response "is why the vaccine can still be effective against this virus," added Edwards, scientific director of the Vanderbilt Vaccine Research Program and professor of pediatrics at the Vanderbilt University School of Medicine in Nashville, Tennessee.

Salvatore emphasized that although the new variant is more transmissible, it doesn't appear to be more lethal. "This might affect overall mortality but not for the individual who gets the infection."

Staying One Step Ahead

When asked for assurance that COVID-19 vaccines will work against emerging variants, Edwards said, "It may be we will have to change the vaccine so it is more responsive to new variants, but at this point that does not seem to be the case."

Should the vaccines require an update, the mRNA vaccines have an advantage — researchers can rapidly revise them. "All you need to do is put all the little nucleotides together," Edwards said.

"A number of us are looking at how this will work, and we look to influenza," she added. Edwards drew an analogy to choosing — and sometimes updating — the influenza strains each year for the annual flu vaccine. With appropriate funding, the same system could be replicated to address any evolving changes to SARS-CoV-2, she said.

On funding, Salvatore said more money would be required to optimize the surveillance system for emerging strains in the United States.

"We actually have this system — there is a wonderful network that sequences the influenza strains," she said. "The structure exists, we just need the funding."

"The CDC is getting the system tooled up to get more viruses to be sequenced," Edwards said.

Both experts praised the CDC for its website with up-to-date surveillance information on emerging strains of SARS-CoV-2.

Biden's Backing of Science

A reporter asked each infectious disease expert to share their impression of Biden's newly signed COVID-19 executive orders.

"The biggest takeaway is the role of science and the lessons we've learned from masks, handwashing, and distancing," Edwards said. "We need to heed the advice...[especially] with a variant that is more contagious.

"It is encouraging that science will be listened to — that is the overall message," she added.

Salvatore agreed, saying that the orders give "the feeling that we can now act by following science."

"We have plenty of papers that show the effectiveness of masking," for example, she said. Salvatore acknowledged that there are "a lot of contrasting ideas about masking" across the United States but stressed their importance.

"We should follow measures that we know work," she said.

Both experts said more research is needed to stay ahead of this evolving scenario. "We still need a lot of basic science showing how this virus replicates in the cell," Salvatore said. "We need to really characterize all these mutations and their functions."

"We need to be concerned, do follow-up studies," she added, "but we don't need to panic."

This article was based on an Infectious Diseases Society of America Media Briefing on January 21, 2021. Salvatore disclosed that she is a site PI on a study from the Verily life sciences LLC/Brin Foundation on Predictors of Severe COVID-19 Outcomes (PRESCO) and PI for an investigator-initiated study sponsored by Genentech on combination therapy in influenza. Edwards disclosed NIH and CDC grants; consulting for Bionet and IBM; and being a member of data safety and monitoring committees for Sanofi, X-4 Pharma, Seqirus, Moderna, Pfizer, and Merck.

Damian McNamara is a staff journalist based in Miami. He covers a wide range of medical specialties, including infectious diseases, gastroenterology, and critical care. Follow Damian on Twitter: @MedReporter.

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