VOA慢速英语:研究称辉瑞公司疫苗对新冠病毒变种同样有效

A new study suggests that Pfizer's COVID-19 vaccine is effective against new forms of the coronavirus discovered in Britain and South Africa.

Researchers say they collected blood from 20 people who received the vaccine, developed by Pfizer and its German partner BioNTech. Antibodies from those individuals were found to work against the coronavirus in laboratory experiments.

Mutated versions, or variants, of the coronavirus first appeared in Britain and South Africa. The two variants have caused concern among world health experts because they appear to spread more easily than the first version. The mutated variant found in Britain has also appeared in the United States and other countries.

The study looked at a change in the so-called "spike" protein that permits the virus to infect human cells. Both new coronavirus variants share the change.

Pfizer and scientists from the University of Texas Medical Branch carried out the new research. Information about the study was recently published online. But outside experts have not yet examined the findings.

The research is limited because it did not examine the full set of mutations in either form of the new variants. However, University of Pennsylvania virus expert Dr. Frederic Bushman told The Associated Press it is likely the new vaccines will work just as well on the virus variants.

The Pfizer-BioNTech vaccine was the first to receive approval for emergency use in the United States. Pfizer has said early trials suggested the vaccine was more than 90 percent effective. The vaccine developed by American drug-maker Moderna and one developed by Oxford University and Britain's AstraZeneca have also been approved for use in some Western countries.

Bushman, who was not part of the Pfizer study, said the Moderna and AstraZeneca vaccines are also being tested against the new variants. He said he expects similar results in those studies. This is because all the vaccines are designed to cause the body to produce antibodies against several parts of the spike protein that covers the virus.

"A mutation will change one little place, but it's not going to disrupt binding to all of them," Bushman said.

Philip Dormitzer is the chief scientific officer for Pfizer. He called findings of the new study "reassuring." He said the research shows the mutation "does not seem to be a problem" for the vaccine.

Dormitzer said the company has tested 16 different virus mutations. So far, none have shown resistance to the vaccine.

Some scientists have expressed greater concern about the new variant found in South Africa.

Simon Clarke is a professor of cellular microbiology at the University of Reading in Britain. He told the Reuters news agency that the South Africa variant "has a number of additional mutations." They include more complex changes to the spike protein.

Such mutations could someday create a need to make changes to the COVID-19 vaccines, just like flu shots must be changed most years.

However, health experts note that both the Pfizer-BioNTech and Moderna vaccines are made with a piece of virus genetic code that is simple to change. Scientists have suggested such changes could be made in as little as six weeks.

I'm Bryan Lynn.

The Associated Press and Reuters reported this story. Bryan Lynn adapted the reports for VOA Learning English. Ashley Thompson was the editor.

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