But there is something else in the air: ominous COVID-19 variants.
I am a virologist and vaccinologist, which means that I spend my days studying viruses and designing and testing vaccine strategies against viral diseases. In the case of COVID-19, this work has taken on greater urgency. We humans are in a race to become immune against this cagey virus, whose ability to mutate and adapt seems to be a step ahead of our capacity to gain herd immunity. Because of the variants that are emerging, it could be a race to the wire.
RNA viruses like COVID-19 constantly mutate as they make more copies of themselves. Most of these mutations end up being disadvantageous to the virus and therefore disappear through natural selection.
Occasionally, though, they offer a benefit to the mutated or so-called genetic-variant virus. An example would be a mutation that improves the ability of the virus to attach more tightly to human cells, thus enhancing viral replication. Another would be a mutation that allows the virus to spread more easily from person to person, thus increasing transmissibility.
None of this is surprising for a virus that is a fresh arrival in the human population and still adapting to humans as hosts. While viruses don't think, they are governed by the same evolutionary drive that all organisms are — their first order of business is to perpetuate themselves.
Currently there are five variants of concern circulating in the U.S.:
B.1.1.7, which originated in the U.K.
B.1.351., of South African origin
P.1., first seen in Brazil
B.1.427, which originated in California
B.1.429, which also originated in California
Each of these variants has a number of mutations, and some of these are key mutations in critical regions of the viral genome. Because the spike protein is required for the virus to attach to human cells, it carries a number of these key mutations. In addition, antibodies that neutralize the virus typically bind to the spike protein, thus making the spike sequence or protein a key component of COVID-19 vaccines.
India and California have recently detected "double mutant" variants that, although not yet classified, have gained international interest. They have one key mutation in the spike protein similar to one found in the Brazilian and South African variants, and another already found in the B.1.427 and B.1.429 California variants. As of today, no variant has been classified as of high consequence, although the concern is that this could change as new variants emerge and we learn more about the variants already circulating.
More Transmission and Worse Disease
These variants are worrisome for several reasons. First, the COVID-19 variants of concern generally spread from person to person at least 20 to 50 percent more easily. This allows them to infect more people and to spread more quickly and widely, eventually becoming the predominant strain.
Another concern is that these new variants can escape the immunity elicited by natural infection or our current vaccination efforts. For example, antibodies from people who recovered after infection or who have received a vaccine may not be able to bind as efficiently to a new variant virus, resulting in reduced neutralization of that variant virus. This could lead to reinfections and lower the effectiveness of current monoclonal antibody treatments and vaccines.
What does this all mean? While current vaccines may not prevent mild symptomatic COVID-19 caused by these variants, they will likely prevent moderate and severe disease, and in particular hospitalizations and deaths. That is the good news.
However, it is imperative to assume that current COVID-19 variants will likely continue to evolve and adapt. In a recent survey of 77 epidemiologists from 28 countries, the majority believed that within a year current vaccines could need to be updated to better handle new variants, and that low vaccine coverage will likely facilitate the emergence of such variants.
What do we need to do? We need to keep doing what we have been doing: using masks, avoiding poorly ventilated areas, and practicing social distancing techniques to slow transmission and avert further waves driven by these new variants.
We also need to vaccinate as many people in as many places and as soon as possible to reduce the number of cases and the likelihood for the virus to generate new variants and escape mutants. And for that, it is vital that public health officials, governments and nongovernmental organizations address vaccine hesitancy and equity both locally and globally.
Paulo Verardi is an associate professor of virology and vaccinology at the University of Connecticut. He receives funding from the National Institutes of Health, United States Department of Agriculture, Department of Defense and the University of Connecticut.
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