[ti:New Versions of the Coronavirus Worry Experts]
[by:www.21voa.com]
[00:00.00]更多听力请访问21VOA.COM
[00:00.04]The fight against the virus
[00:02.72]that causes COVID-19 has taken a new turn:
[00:09.28]Reports of mutations are appearing quickly.
[00:14.04]Many scientists fear that a variant of the new coronavirus
[00:21.12]may appear that cannot be prevented
[00:24.72]by a known treatment or vaccine.
[00:29.32]The genes of the coronavirus are changing,
[00:33.92]and health officials say the high number of new cases
[00:39.16]is the main reason.
[00:41.52]Each new infection gives the virus a chance to mutate
[00:47.68]as it makes copies of itself.
[00:51.24]Each mutation threatens to undo the progress made
[00:57.16]in the last year of fighting the pandemic.
[01:01.56]On Friday, the World Health Organization
[01:05.96]urged more efforts to find new variants.
[01:11.20]The U.S. Centers for Disease Control and Prevention
[01:15.88]said a new variant first identified in Britain a few months ago
[01:22.32]might become the number one virus in the U.S. by March.
[01:28.16]It does not cause more severe illness,
[01:32.32]but it could cause more hospitalizations and deaths.
[01:37.52]The CDC warned of coming "exponential growth."
[01:43.16]"We're taking it really very seriously," Dr. Anthony Fauci
[01:50.16]said on American television Sunday.
[01:53.88]He is the U.S. government's top infectious disease expert.
[02:00.20]"We need to do everything we can now...
[02:03.72]to get transmission as low as we possibly can,"
[02:08.16]said Harvard University's Dr. Michael Mina.
[02:12.96]He said that the best way to stop mutations
[02:17.40]is to slow the spread of the virus.
[02:21.08]So far, vaccines remain effective.
[02:25.32]There are, however, signs that some tests
[02:29.56]and drug treatments may not work with the new variants.
[02:35.92]The virus may create a mutation that makes it more dangerous,
[02:41.20]said Dr. Pardis Sabeti.
[02:44.96]She is an evolutionary biologist
[02:48.20]at the Broad Institute of MIT and Harvard.
[02:52.72]For example, younger people may not be afraid of the virus
[02:58.24]because it does not make them very sick.
[03:01.52]That could change quickly, she warned.
[03:06.08]It is normal for viruses to mutate.
[03:09.96]A mutation that strengthens the virus
[03:13.80]helps it to survive by pushing out the weaker variants.
[03:19.40]Just a few months after the coronavirus was discovered ,
[03:24.32]a mutation called D614G began to spread.
[03:30.64]It quickly became a major form of the virus.
[03:35.92]Trevor Bedford is a biologist
[03:39.00]with the Fred Hutchinson Cancer Research Center in Seattle.
[03:44.92]Last week, he wrote on Twitter,
[03:47.88]now, "we've started to see some striking evolution" of the virus.
[03:54.08]New variants have also been found in South Africa and Brazil.
[04:00.64]A main mutation in the variant identified in Britain
[04:05.32]appears to be in another variant
[04:08.28]that was found in Ohio, said Dan Jones.
[04:13.36]He is a molecular pathologist at Ohio State University
[04:18.84]who announced that finding last week.
[04:22.40]This is important because it does not appear the mutation
[04:27.12]was created as the result of travel.
[04:30.72]Rather, the virus may mutate
[04:33.40]in the same way in different places, Jones said.
[04:38.36]That also means that travel restrictions might be ineffective, Mina said.
[04:44.88]Because the United States has so many cases,
[04:48.96]"we can breed our own variants that are just as bad or worse"
[04:54.56]as those in other countries, he said.
[04:58.64]Government scientists are "actively looking" into the possibility
[05:03.92]that variants found in South Africa and Brazil
[05:08.20]may be able to fight off antibody drugs and other treatments
[05:13.28]that can help people survive COVID-19,
[05:17.72]Dr. Janet Woodcock of the U.S. Food and Drug Administration
[05:23.56]told reporters Thursday.
[05:26.56]Other scientists are not as worried.
[05:30.28]Dr. Andrew Pavia of the University of Utah
[05:35.16]said vaccines in use now should remain effective.
[05:40.16]They may need a small change to fight mutations.
[05:45.04]Even then, he said, "it's probably going to be on the order of years
[05:51.48]if we use the vaccine well rather than months."
[05:56.16]He was speaking Thursday on a webcast
[05:59.64]run by the Infectious Diseases Society of America.
[06:05.20]I'm Susan Shand. 更多听力请访问21VOA.COM
END OF TRACK. "END OF TRACK." The two men bowed. "Whoever was that person you were talking to?" she enquired, as soon as they stood together. The took of triumph faded from her eyes, she had grown worn and weary. The roses were wilting on the walls, the lights were mostly down now. Hetty, looking in to see if anything was wanted, found herself driven away almost fiercely. I only saw Master Jervie once when he called at tea time, The year 1747 was opened by measures of restriction. The House of Lords, offended at the publication of the proceedings of the trial of Lord Lovat, summoned the parties to their bar, committed them to prison, and refused to liberate them till they had pledged themselves not to repeat the offence, and had paid very heavy fees. The consequence of this was that the transactions of the Peers were almost entirely suppressed for nearly thirty years from this time, and we draw our knowledge of them chiefly from notes taken by Horace Walpole and Lord Chancellor Hardwicke. What is still more remarkable, the reports of the House of Commons, being taken by stealth, and on the merest sufferance, are of the most meagre kind, sometimes altogether wanting, and the speeches are given uniformly under fictitious names; for to have attributed to Pitt or Pelham their[112] speeches by name would have brought down on the printers the summary vengeance of the House. Many of the members complained bitterly of this breach of the privileges of Parliament, and of "being put into print by low fellows"; but Pelham had the sense to tolerate them, saying, "Let them alone; they make better speeches for us than we can make for ourselves." Altogether, the House of Commons exhibited the most deplorable aspect that can be conceived. The Ministry had pursued Walpole's system of buying up opponents by place, or pension, or secret service money, till there was no life left in the House. Ministers passed their measures without troubling themselves to say much in their behalf; and the opposition dwindled to Sir John Hinde Cotton, now dismissed from office, and a feeble remnant of Jacobites raised but miserable resistance. In vain the Prince of Wales and the secret instigations of Bolingbroke and Doddington stimulated the spirit of discontent; both Houses had degenerated into most silent and insignificant arenas of very commonplace business. "It certainly will be. Miss Widgeon," answered Maria, with strictly "company manners." "One who has never had a brother exposed to the constant dangers of army life can hardly understand how glad we all feel to have Si snatched from the very jaws of death and brung back to us." "Just plug at 'em as you would at a crow, and then go on your way whistlin'?" persisted Harry. "Hurroo!" echoed Hennessey; "that's the ticket." "Come forward, keeper," continued the baron, "and state how these arrows came into your hands!" "Yes." HoMEJULIA京香2018下载
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