辉瑞称其加强针可以预防Omicron

American drugmaker Pfizer said on Wednesday that the third shot, or booster, of its COVID-19 vaccine will protect people against the Omicron variant of the virus.

Pfizer and its German partner BioNTech said early lab tests show the booster increased levels of virus-fighting antibodies by "25-fold."

The Pfizer research is early and has not been independently examined.

A statement from Pfizer's top officer, Albert Bourla, said the two-shot vaccine still offers protection against severe disease caused by Omicron. But, Bourla said, "it's clear from these preliminary data that protection is improved with a third dose of our vaccine."

The company also said it has started to develop a COVID-19 vaccine against Omicron. If needed, the new vaccine will be ready by March 2022.

The findings are similar to a small study published by researchers at the Africa Health Research Institute in South Africa on Tuesday. The South African study also suggested that a third shot might help against Omicron infection.

However, Reuters reported that a study at the University Hospital of Frankfurt, Germany, found reduced antibody levels against Omicron even after three shots.

Independent experts have not reviewed the studies.

Health officials still do not know how big of a threat Omicron really is. The Delta variant is still responsible for most of the cases, especially in the United States.

Omicron was first identified in Africa on November 9 and reported to the World Health Organization (WHO) on November 24. Two days later, the WHO designated it a variant of concern, or VOC.

The agency said Omicron "has a large number of mutations, some of which are concerning." A mutation is a change in the genetic material of a virus. The WHO added that early evidence suggests "an increased risk of reinfection with this variant, as compared to other VOCs."

Several countries, including the United States, Brazil, Japan, and Israel, restricted travelers from some African countries. But the variants have since been identified throughout Europe, North America and Australia.

I'm Jonathan Evans.

Hai Do wrote this story for Learning English. Caty Weaver was the editor.

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fold - n. a word to describe a quantity changes between an original and a subsequent measurement

preliminary - adj. coming before something

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