VOA慢速英语2021--强生单剂疫苗在南非效果不如美国

American drugmaker Johnson & Johnson said Friday that its one-shot vaccine¹ prevented COVID-19 in a large trial around the world. The vaccine, however, was less effective in South Africa where a worrisome variant² is causing new infections.

The Johnson & Johnson, or J&J, trial involved almost 44,000 volunteers. The company said the vaccine worked best in the United States with an efficacy rate of 72 percent. In Latin America, efficacy was 66 percent. J&J reported that South Africa saw the lowest efficacy rate of the vaccine, at 57 percent.

On Thursday, another American company, Novavax, reported its own COVID-19 vaccine candidate was 89 percent effective among volunteers in Britain. But the results dropped to 49 percent with a smaller group of volunteers in South Africa.

The two-shot vaccines³ from Pfizer-BioNTech and Moderna were found to be nearly 95 percent effective against COVID-19 in large trials. Those trials, however, were held mainly in the U.S. And they took place before the spread of the new coronavirus variants⁴ from Britain, Brazil and South Africa.

Dr. Paul Stoffels is J&J's chief scientific officer. He noted⁵ that the World Health Organization considers a one-shot treatment to be the best choice to vaccinate⁶ people during a pandemic. Stoffels also pointed⁷ to the trial's finding that the vaccine is 85 percent effective in preventing severe COVID-19. This offers "hope of helping⁸ ease the huge burden placed on healthcare systems and communities," he said.

Dr. Anthony Fauci is the U.S. government's top infectious disease expert. He said the Johnson & Johnson study was "very encouraging."

At a coronavirus briefing Friday, Fauci called the emerging variants "a wake-up call for all of us." He added that the best way to prevent more coronavirus variants is by "vaccinating⁹ as many people as you possibly can."

J&J said it will seek U.S. Food and Drug Administration permission in early February for emergency use of the vaccine. The agency requires a 50 percent or better efficacy rate to be approved for emergency use.

COVID-19 variants

Like other viruses, SARS-CoV-2, the coronavirus that causes COVID-19, is continually changing. Sometimes new variants appear and disappear. Other times, new variants appear and spread across many countries.

Medical experts are especially concerned about the three SARS-CoV-2 variants that came from Britain, Brazil and South Africa. The U.S. government's Centers for Disease Control and Prevention (CDC) says they appear to spread more easily and quickly than other variants.

In Britain, a coronavirus variant known as B.1.1.7 was first recognized in September 2020. It quickly spread throughout the country and now is spreading throughout Europe, the United States and Canada.

The coronavirus variant called P.1 was first identified in four travelers from Brazil who were tested at an airport near Tokyo, Japan in January. It has spread to many countries including Germany, South Korea and the U.S.

In South Africa, another variant called B.1.351 appeared in early October. It has since spread to more than 30 countries including Australia, South Korea and Germany. On Thursday, American health officials reported the appearance of the South African variant in the U.S. They identified two cases in the state of South Carolina. The patients had no links to one another and neither had traveled recently. The experts say this suggests community spread started with a yet unidentified carrier.

At this time, U.S. health agency experts says there is no evidence that new coronavirus variants cause more severe sickness or increased risk of death.

However, scientists have reported that antibodies from a small number of people who had recovered from COVID-19 were less effective against the variant from South Africa. Now, the results from J&J and Novavax trials confirm that current vaccines might be less effective against the South African variant than others.

Both Moderna and Pfizer have since announced they are testing a booster of the approved vaccines against the new variants.

Words in This Story

variant - n. something (the virus) that is different in some way from others of the same kind

burden - n. something that is difficult to deal with

encouraging - adj. causing hopeful feeling

booster - n. something that helps

1 vaccine   

n.牛痘苗，疫苗；adj.牛痘的，疫苗的

参考例句：

• The polio vaccine has saved millions of lives.脊髓灰质炎疫苗挽救了数以百万计的生命。
• She takes a vaccine against influenza every fall.她每年秋季接种流感疫苗。

2 variant   

adj.不同的，变异的；n.变体，异体

参考例句：

• We give professional suggestions according to variant tanning stages for each customer.我们针对每位顾客不同的日晒阶段，提供强度适合的晒黑建议。
• In a variant of this approach,the tests are data- driven.这个方法的一个变种，是数据驱动的测试。

3 vaccines   

疫苗，痘苗( vaccine的名词复数 )

参考例句：

• His team are at the forefront of scientific research into vaccines. 他的小组处于疫苗科研的最前沿。
• The vaccines were kept cool in refrigerators. 疫苗放在冰箱中冷藏。

4 variants   

n.变体( variant的名词复数 )；变种；变型；（词等的）变体

参考例句：

• Those variants will be preserved in the'struggle for existence". 这些变异将在“生存竞争”中被保留下来。 来自辞典例句
• Like organisms, viruses have variants, generally called strains. 与其他生物一样，病毒也有变种，一般称之为株系。 来自辞典例句

5 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

6 vaccinate   

vt.给…接种疫苗；种牛痘

参考例句：

• Local health officials then can plan the best times to vaccinate people.这样，当地的卫生官员就可以安排最佳时间给人们接种疫苗。
• Doctors vaccinate us so that we do not catch smallpox.医生给我们打预防针使我们不会得天花。

7 pointed   

adj.尖的，直截了当的

参考例句：

• He gave me a very sharp pointed pencil.他给我一支削得非常尖的铅笔。
• She wished to show Mrs.John Dashwood by this pointed invitation to her brother.她想通过对达茨伍德夫人提出直截了当的邀请向她的哥哥表示出来。

8 helping   

n.食物的一份&adj.帮助人的，辅助的

参考例句：

• The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。
• By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。

9 vaccinating   

给…接种疫苗( vaccinate的现在分词 )； 注射疫苗，接种疫苗

参考例句：

• At first blush, vaccinating the wolves against rabies seems a simple solution. 乍一看来，为狼群注射防狂犬病疫苗是一种简单的办法。
• Also vaccinating children against misers (measles) has saved many lives. 还有，给儿童进行疫苗接种防止麻疹也挽救了许多生命。