Variants could complicate pandemic in coming months ‘but we do not need to panic’
CDC researchers reported recently that a more highly transmissible SARS-CoV-2 variant first detected in the United Kingdom could soon become the dominant variant in the United States, potentially complicating the U.S. response.
This week, scientists in South Africa said tests showed that a variant first reported in that country “is largely resistant to neutralizing antibodies elicited by infection with previously circulating lineages.”
“This suggests that, despite the many people who have already been infected with SARS-CoV-2 globally and are presumed to have accumulated some level of immunity, new variants ... pose a significant re-infection risk,” the scientists wrote in a non-peer-reviewed paper that was published on the preprint server bioRxiv.
Moreover, they said the findings “may foreshadow reduced efficacy of current spike-based vaccines.”
During an Infectious Diseases Society of America press briefing on Thursday, Kathryn Edwards, MD, said that although COVID-19 vaccines may need to be modified to account for variants in the future, this action is not currently necessary. Edwards, who heads the Vanderbilt Vaccine Research Program, said some tests have been modified because of mutations in the virus’ spike protein.
“We will be evolving and responding to these issues,” she said.
The U.K. variant, known as B.1.1.7 — which was reported for the first time in the U.S. last month in a Colorado man — is more transmissible than the original virus but does not cause more severe symptoms, according to scientists. It may be 50% more transmissible, Summer E. Galloway, PhD, a senior global health policy advisor at the CDC, and colleagues noted in MMWR.
The Pfizer-BioNTech vaccine has been shown to be effective against both the U.K. and South African variants of the virus, and Moderna has said that it expects its vaccine also will work against them. Still, the U.K. variant’s increased transmissibility “warrants universal and increased compliance with mitigation strategies, including distancing and masking,” Galloway and colleagues wrote. “Higher vaccination coverage might need to be achieved to protect the public.”
In their study, Galloway and colleagues used a two-variant compartmental model to estimate the potential impact of B1.1.7 growth in the U.S. population. Assumptions for the model were that 1 million vaccine doses were administered per day beginning Jan. 1, 2021, and that 95% immunity is achieved 14 days following the administration of two doses. Immunity to infection with the B.1.17. variant also was assumed.
They found that although B.1.1.7 prevalence is low, its transmissibility will lead to “rapid growth” throughout early 2021, potentially making it the dominant variant in the U.S. by March.
Mirella Salvatore, MD, FIDSA, assistant professor of medicine and population health sciences at Weill Cornell Medicine, said “worrying and panicking [about the variants] should not be the priority.”
“We are in front of a virus that is potentially more transmissible and have begun worrying about what we cannot change. Each of us should follow the health prevention that we know works — masking, distancing, washing your hands and getting vaccinated. This will help in preventing the spread of the virus,” Salvatore said during the IDSA briefing.
According to Salvatore, the transmissibility of variants depends on the virus’ location, the level of immunity in the population and people’s behavior. She said the U.S. has the ability to detect variants, but that more funding and better organization is necessary to do it effectively. (The CDC said recently that it was stepping up efforts to sequence more samples so that variants can be detected more quickly.)
Salvatore said that although the current variants are not inherently more lethal, they “affect overall lethality” as they spread throughout the population. She said further research is needed to properly address variants and that “we still need a lot of basic science to show how this virus replicates in the cell.”
Salvatore noted that another preprint study, also published on bioRxiv, produced more encouraging results, showing that there appears to be a decreased effect “but the neutralization of the vaccine of the sera from people that were vaccinated still happens.”
“We need to follow the studies,” Salvatore said, “but we do not need to panic.”