Rise of a trio of mutated viruses hints at an increase in transmissibility, speeding the virus’ leaps from one host to the next
Reporter: Aviva Lev-Ari, PhD, RN
“We have uncontrolled viral spread in much of the world,” says Adam Lauring, an infectious disease physician and virologist at the University of Michigan. “So the virus has a lot of opportunity to evolve.”
“The variants may be more transmissible, but physics has not changed,” says Müge Çevik, an infectious disease physician at the University of St. Andrews in Scotland.
Many changes don’t affect the virus’ function, and some even harm SARS-CoV-2’s ability to multiply, but they keep happening. “Viruses mutate; that’s what they do,” says Akiko Iwasaki, an immunologist at Yale School of Medicine in Connecticut.
U.K., Brazil, and South Africa. In the United Kingdom, variant B.1.1.7 likely drove the region’s record-setting spike of COVID-19 cases in January. The variant is now circulating in more than 60 countries, including the United States—and projections suggest it will become the most common virus variety in the U.S. by mid-March.
An independently arising lineage called P.1 might also be driving a wave of cases in Manaus, Brazil, where it accounted for nearly half of new COVID-19 infections in December. On January 26, Minnesotan officials reported the first U.S. case of P.1 in a resident who previously traveled to Brazil. And a third lineage raising alarms, known as B.1.351, was first spotted amid a December wave of infections in South Africa. On January 28, the first known U.S. cases of the variant were reported in South Carolina.
One specific mutation, known as N501Y, popped up independently in all three variants, suggesting it could provide an advantage to the virus. “That’s a sign that there is natural selection going on,” Lauring says. The N501Y mutation affects the virus’ spike protein, which is the key it uses to unlock entry into its host’s cells.
Another possibility is that new variants cause people who are infected to harbor more copies of the virus. This results in greater viral “shedding” in airborne droplets spewed when people talk, sing, cough, and breath.
mutations in 501Y.V2 could diminish the effectiveness of antibodies in the blood of people previously infected with the virus. But understanding whether that could lead to more re-infections, or if it could affect vaccine efficacy.
Dramatically scale up production of high-filtration masks for the general public.
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