Cell process may explain why coronavirus variants are more infectious, NIH study shows

Scientists at the National Institutes of Health said they have gained new insight into the coronavirus alpha and delta variants, possibly explaining why the mutations are more transmissible and infectious than the original strain.

Their study and findings were published online in the Proceedings of the National Academy of Sciences.

Scientists said the outer surface of the virus is decorated with spike proteins, which the virus uses to attach and enter host cells. But before entering the host cell, the spike proteins of the virus must be activated by a series of cuts, or cleavages.

NIH scientists said their study led them to believe that spike proteins of the alpha and delta variants produce more cleavages, making them easier to attach and enter the host cells leading to an infection. Furthermore, scientists said the variants have found a way to decrease bulky sugar molecules in host cells, thus allowing them to produce more cleavages. 

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"I think we are gaining a better understanding of what these [COVID-19] mutations are actually doing," Dr. Kelly Ten Hagen, the lead researcher, said in an interview with FOX Television Stations Tuesday. "Knowing what they’re doing gives us a lot more potential tools to be able to develop strategies to tackle it moving forward."

Ten Hagen said the study is the first step in possibly understanding why the coronavirus alpha and delta variants are more transmissible. She said the study would need to be replicated and further research is needed. 

If the theory holds up, Ten Hagen said that would allow scientists to develop more effective antiviral treatments to combat the coronavirus — but she still urges people to get a vaccine. 

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"Honestly, vaccines, I think, are probably the number one strategy right now," she continued. 

Efforts to combat the COVID-19 pandemic continue to grow. U.S. health officials blamed the summer surge of COVID-19 infections on the more transmissible delta variant. The delta variant filled hospitals, sickened an increasing number of children and drove coronavirus deaths in some places to the highest levels of the entire pandemic. Some school systems that reopened their classrooms abruptly switched back to remote learning because of outbreaks. Legal disputes, threats and violence erupted over mask and vaccine requirements.

Earlier this year, the alpha, or B.1.1.7 variant, became the most prevalent strain of the novel coronavirus in the U.S. The delta strain took over mid-summer.

This month, U.S. health officials allowed children as young as five years old to get the Pfizer COVID-19 vaccine. A Pfizer study of 2,268 children found the vaccine was almost 91% effective at preventing symptomatic COVID-19 infections. The FDA examined 3,100 vaccinated kids in concluding the shots are safe.

Infected kids have contributed to the U.S. toll, which sits at 46 million total infections and more than 740,000 deaths.

RELATED: Pfizer asks FDA to authorize COVID-19 booster shot for all adults over age of 18

On Tuesday, Pfizer and BioNTech announced they have submitted a request for emergency use authorization from the U.S. Food and Drug Administration for a COVID-19 vaccine booster for all U.S. adults aged 18 and older.

Pfizer also said that its experimental antiviral pill for COVID-19 cut rates of hospitalization and death by nearly 90% in high-risk adults, as the drugmaker joined the race for an easy-to-use medication to treat the coronavirus. Currently, most COVID-19 treatments require an IV or injection. Competitor Merck’s COVID-19 antiviral pill is already under review at the FDA after showing strong initial results. The United Kingdom became the first country to OK it earlier this month.

The Associated Press contributed to this report. This story was reported from Los Angeles.