[ti:Study: Pfizer Vaccine Appears Effective Against COVID-19 Variants] [by:www.51voa.com] [00:00.00]更多听力请访问51VOA.COM [00:00.04]A new study suggests that Pfizer's COVID-19 vaccine [00:05.76]is effective against new forms of the coronavirus [00:11.44]discovered in Britain and South Africa. [00:16.60]Researchers say they collected blood from 20 people [00:21.80]who received the vaccine, [00:24.20]developed by Pfizer and its German partner BioNTech. [00:30.68]Antibodies from those individuals were found to work [00:35.76]against the coronavirus in laboratory experiments. [00:41.96]Mutated versions, or variants, of the coronavirus [00:47.52]first appeared in Britain and South Africa. [00:53.08]The two variants have caused concern among world health experts [00:58.88]because they appear to spread more easily than the first version. [01:06.04]The mutated variant found in Britain [01:09.64]has also appeared in the United States and other countries. [01:16.12]The study looked at a change in the so-called "spike" protein [01:21.76]that permits the virus to infect human cells. [01:26.72]Both new coronavirus variants share the change. [01:32.88]Pfizer and scientists from the University of Texas Medical Branch [01:38.88]carried out the new research. [01:42.48]Information about the study was recently published online. [01:48.68]But outside experts have not yet examined the findings. [01:54.64]The research is limited because it did not examine [01:59.12]the full set of mutations in either form of the new variants. [02:05.64]However, University of Pennsylvania virus expert Dr. Frederic Bushman [02:12.28]told The Associated Press it is likely the new vaccines [02:17.56]will work just as well on the virus variants. [02:22.88]The Pfizer-BioNTech vaccine was the first to receive approval [02:28.96]for emergency use in the United States. [02:33.52]Pfizer has said early trials suggested the vaccine [02:38.48]was more than 90 percent effective. [02:43.00]The vaccine developed by American drug-maker Moderna [02:47.60]and one developed by Oxford University and Britain's AstraZeneca [02:53.84]have also been approved for use in some Western countries. [03:00.56]Bushman, who was not part of the Pfizer study, [03:04.72]said the Moderna and AstraZeneca vaccines [03:08.96]are also being tested against the new variants. [03:14.28]He said he expects similar results in those studies. [03:20.44]This is because all the vaccines are designed [03:24.24]to cause the body to produce antibodies against several parts [03:29.80]of the spike protein that covers the virus. [03:34.72]"A mutation will change one little place, [03:38.60]but it's not going to disrupt binding to all of them," Bushman said. [03:46.00]Philip Dormitzer is the chief scientific officer for Pfizer. [03:52.24]He called findings of the new study "reassuring." [03:57.28]He said the research shows the mutation [04:00.76]"does not seem to be a problem" for the vaccine. [04:05.72]Dormitzer said the company has tested 16 different virus mutations. [04:12.48]So far, none have shown resistance to the vaccine. [04:19.08]Some scientists have expressed greater concern [04:23.24]about the new variant found in South Africa. [04:28.40]Simon Clarke is a professor of cellular microbiology [04:33.20]at the University of Reading in Britain. [04:37.16]He told the Reuters news agency that the South Africa variant [04:42.20]"has a number of additional mutations." [04:46.40]They include more complex changes to the spike protein. [04:52.48]Such mutations could someday create a need [04:56.28]to make changes to the COVID-19 vaccines, [05:00.16]just like flu shots must be changed most years. [05:06.12]However, health experts note that both the Pfizer-BioNTech [05:11.56]and Moderna vaccines are made with a piece of virus [05:16.12]genetic code that is simple to change. [05:20.76]Scientists have suggested [05:23.24]such changes could be made in as little as six weeks. [05:28.68]I'm Bryan Lynn. 更多听力请访问51VOA.COM