VOA慢速英语2020--辉瑞声称其COVID疫苗有效率为90%（在线收听）

Pfizer Says Its COVID-19 Vaccine 90 Percent Effective

From VOA Learning English, this is the Health and Lifestyle Report.

American drug-maker Pfizer says its experimental vaccine appears to be more than 90 percent effective in preventing COVID-19.

The information came Monday from early results of a Phase 3 study involving about 44,000 volunteers in the United States and other countries. An independent group of scientists also examined the study.

Pfizer and its German partner BioNTech are the first drug-makers to show successful data from a large Phase 3 trial of a coronavirus vaccine. The companies also said they have found no serious safety concerns in the testing so far. And they expect to seek emergency use permission from the U.S. Food and Drug Administration (FDA) later this month.

Albert Bourla is Pfizer's chairman and chief. He said in a statement, "Today is a great day for science and humanity. The first set of results from our Phase 3 COVID-19 vaccine trial provides the initial evidence of our vaccine's ability to prevent COVID-19."

Bourla added, "With today's news, we are a significant step closer to providing people around the world with a much-needed breakthrough to help bring an end to this global health crisis. We look forward to sharing additional efficacy and safety data generated from thousands of participants in the coming weeks."

Johns Hopkins University's Coronavirus Resource Center reported that the health crisis has infected more than 50 million people around the world with 1.2 million deaths.

Jesse Goodman is an infectious diseases expert at Georgetown University and a former FDA chief scientist. He told the Associated Press, "We need to see the data, but this is extremely promising."

Dr. Goodman noted several questions that remain to be answered, including how long the vaccine's effects last and whether it protects older people as well as younger people.

"It's going to be a while before this has a major impact at the population level," he said.

Emergency use authorization

In order to receive FDA's emergency use permission, Pfizer will need to present at least two months of safety data collected on the study's 44,000 volunteers. The information is expected to come by the third week of November. Drug-makers Pfizer and BioNTech will continue to follow the study volunteers for another two years after their second vaccine treatment.

Pfizer said the early finding involved 94 volunteers in the trial who developed COVID-19. Volunteers in the late Phase 3 study and the researchers do not know who received the real experimental vaccine or an inactive substance.

The drug-maker did not say how many of those who got COVID-19 had been treated with the vaccine candidate. However, a 90 percent effectiveness suggests that about 8 out of the 94 volunteers who caught COVID-19 had received the experimental vaccine.

Pfizer plans to continue the study until it records 164 COVID-19 infections among all the volunteers. That is a number that the FDA says is enough to tell how well the vaccine is working. The agency requires a vaccine be at least 50 percent effective for emergency use.

The data has yet to be re-examined or published in a medical journal. Pfizer and BioNTech said it would take action once it has results from the entire trial.

When will COVID-19 vaccine be available?

Pfizer and BioNTech COVID-19 vaccine uses a biotechnology called messenger RNA, or mRNA. The genetically-engineered material causes the body to create a protein to protect against the virus.

No mRNA technology has ever been approved for use in people. The material can be created and manufactured in weeks, much faster than conventional vaccines.

Pfizer and BioNTech have a $1.95 billion contract with the United States government to provide 100 million vaccine treatments. They have also reached agreements with the European Union, Britain, Canada and Japan.

Pfizer said it expects to produce up to 50 million doses of vaccine in 2020 and up to 1.3 billion doses in 2021.

American drug-maker Moderna also uses messenger-RNA technology in their Phase 3 experimental vaccine. Other COVID-19 vaccine candidates in Phase 3 trials come from drug companies Johnson and Johnson and AstraZeneca, which is working with the University of Oxford.

China says it has three vaccine candidates undergoing Phase 3 human trials and Russia says it has one.

Words in This Story

initial - adj. happening at the beginning

significant - adj. very important

global - adj. involving the entire world

impact - n. a powerful or major influence or effect

dose - n. the amount of medicine that is taken at one time