源 稿 窗
在文章中双击或划词查词典
字号 +
字号 -
折叠显示
全文显示
One year after the World Health Organization declared the COVID-19 outbreak a pandemic, a new study has found that a variant of the virus first detected in Britain is deadlier than other previous versions.
A study published Wednesday in the British Medical Journal said people infected with the B.1.1.7 variant were between 30% to 100% more likely to die than others infected with other versions, with the average rate about 64%.
The B.1.1.7 variant has been detected in more than 100 countries since it was first detected last September in southeast Britain. Previous studies show the variant is far more contagious than the original version.
Brazil posted 2,286 COVID-19 related deaths on Wednesday, another single-day record number of fatalities. The South American country is dealing with a dramatic surge of coronavirus cases driven by the new P.1 variant, which was discovered last November in the Amazonian regional city of Manaus. Researchers say the P.1 variant is 1.4 to 2.4 times more transmissible than the original version of the coronavirus, and could also reinfect people already recovering from COVID-19.
According to Johns Hopkins Coronavirus Resource Center, Brazil has 11.2 million of the world's 118 million total COVID-19 infections, just third behind the United States and India, while its 270,656 deaths is second only to the U.S. and its 529,203 fatalities.
As many nations struggle to vaccinate their citizens against the novel coronavirus, U.S. President Joe Biden is promising to share any surplus of the single-shot vaccine developed by Johnson & Johnson with the world. Biden made the pledge Wednesday when he announced the U.S. would purchase another 100 million more doses of the Johnson & Johnson vaccine to boost the nation's COVID-19 supply.
"This is not something that can be stopped by a fence no matter how high you build a fence or wall," the president said. "So we're not going to be ultimately safe until the world is safe."
Last month, Biden pledged $4 billion to the World Health Organization's global vaccine sharing program, COVAX, which purchases vaccines with the help of wealthier countries and distributes them equitably to all countries.
A group of U.S. researchers say that people who have already been infected with COVID-19 only need a single dose of the two-shot Pfizer-BioNTech or Moderna regimen. In a letter published Wednesday in the New England Journal of Medicine, 32 scientists with the Icahn School of Medicine at Mount Sinai, New York, said a small study reveals that people who had recovered from the virus developed about 10 to 45 times as many antibodies after their first dose as the average uninfected person.
More researchers have accepted a theory that once a person has had COVID-19, their immune system will mount a stronger and quicker defense once a vaccine triggers the body to start producing antibodies again.