Decline in COVID-19 cases may be short-lived, thanks to highly infectious mutant strains

CDC Director Dr. Rochelle Walensky warned that highly transmissible mutant strains may soon take off in the U.S.

By Matthew Rozsa
February 27, 2021 2:00AM (UTC)
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Doctors and nurses taking care of patients in ICU at hospital during COVID-19 (Getty Images)

The much-celebrated decline in COVID-19 cases may be short-lived. And a mutant is to blame. 

Indeed, President Joe Biden's newly-appointed director for the Centers for Disease Control and Prevention (CDC) says that mutant strains of the coronavirus may be stalling the recovery in coronavirus case count that we've been seeing since January.

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"Over the last few weeks, cases and hospital admissions in the United States have been coming down since early January, and deaths have been declining in the past week," Dr. Rochelle Walensky told reporters during a press briefing. "But the latest data suggest that these declines may be stalling, potentially leveling off at still a very high number."

Like most viruses, SARS-CoV-2 (the virus responsible for COVID-19) often mutates as it reproduces, raising concerns that new strains of the virus could cause more infections, make the disease more dangerous or help the virus evade vaccines. And this is precisely what its more successful mutant strains have been doing.

On its website, the CDC identified three mutant strains that its researchers find particularly alarming. The first is B.1.1.7, which originated in the United Kingdom and is considered much more transmissible than other coronavirus variants. B.1.1.7 was first reported in the United States at the end of December 2020.

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Early reports indicate that B.1.1.7 may be associated with higher rates of death than other strains of the novel coronavirus, although this has not been confirmed. The B.1.1.7 strain was also reported in California to have merged with another variant of the virus to create a hybrid called B.1.429.

Another mutant strain, which originated in South Africa, was first reported in the United States at the end of January 2021. Known as either B.1.351 lineage or 20C/501Y.V2, this variant is particularly alarming because it may affect vaccine efficacy. The South African government revealed earlier this month that the SARS-CoV-2 vaccine developed by AstraZeneca and the University of Oxford had failed to protect clinical trial volunteers from this variant. 

Like B.1.1.7, B.1.351 has a mutation at the protein known as Spike. The Spike protein gives the coronavirus those little nubs that poke out of it like the spines on a sea urchin. mRNA vaccines like those manufactured by Pfizer and Moderna work by helping the immune system recognize and target those spines, although there is no definitive evidence that it will be able to evade those vaccines. As Dr. Eric Feigl-Ding, senior fellow at the Federation of American Scientists, told Salon earlier this month, "other vaccines do work for the B.1.351 variant even if AstraZeneca doesn't."

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Another variant, which originated in Brazil, is called P.1. It includes a number of mutations, including three in the receptor binding domain of the spike protein. That one was also first detected in the United States at the end of January 2021.

At the time of this writing, roughly 28.5 million cases of COVID-19 have been detected in the United States leading to more than 500,000 deaths. Public health officials and scientists urge Americans to practice basic hygiene measures including regular hand washing, wearing masks in public that cover your nose and mouth, social distancing in public and getting vaccinated as soon as possible.


Matthew Rozsa

Matthew Rozsa is a staff writer for Salon. He holds an MA in History from Rutgers University-Newark and is ABD in his PhD program in History at Lehigh University. His work has appeared in Mic, Quartz and MSNBC.

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