Scientists Watching Delta Variant for Changes
2021-11-23
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1The Delta variant of the SARS-CoV-2 virus is responsible for most cases of coronavirus infections worldwide, scientists say.
2The COVID-19 vaccines work well against the variant so far.
3Fully vaccinated people who get infected rarely require hospital stays or die from the disease, medical experts say.
4But scientists continue to watch Delta closely for changes.
5The Delta variant, first identified in India in December 2020, remains the most troubling kind of SARS-CoV-2 virus.
6The World Health Organization describes Delta as a variant of concern.
7That means the variant can increase disease spread, cause more severe disease or reduce the effects of vaccines and treatments.
8Shane Crotty is a virus expert at the La Jolla Institute for Immunology in San Diego.
9He described Delta's ability to spread as a "superpower."
10Delta is able to spread more than two times faster than other SARS-CoV-2 variants, says the U.S. Centers for Disease Control and Prevention.
11Studies suggest it may be more likely to put infected people in the hospital than earlier forms of the virus.
12Delta also can cause symptoms two to three days sooner than the original SARS-CoV-2, giving the immune system less time to put up a defense.
13People infected with Delta carry around 1,200 times more virus in their noses compared with the first kind of the coronavirus.
14The amount of virus in vaccinated individuals who become infected with Delta is about the same as those who are unvaccinated.
15And both vaccinated and unvaccinated people can spread the virus to others.
16In vaccinated people, however, the amount of virus drops more quickly, so they likely spread the virus for a shorter time.
17The WHO says Delta makes up 99.5 percent of all genetic samples of coronavirus infection reported to public databases.
18However, in South America, where Delta has spread more slowly, other variants such as Gamma, Lambda and Mu still make up a large number of reported cases.
19Many vaccine experts predict that all future variants will develop from Delta.
20One such variant is known as AY.4.2.
21In Britain, the variant represents 10 percent of virus samples.
22The British government's health security agency has named the AY.4.2 a "Variant Under Investigation."
23Officials say an early study suggests the variant does not substantially reduce vaccine effectiveness in comparison to Delta.
24However, there is some evidence that AY.4.2 could spread more easily than the older Delta, the agency said.
25AY.4.2 has spread to at least 42 countries, including the United States.
26Virus experts are closely watching the evolution of Delta.
27While current vaccines prevent severe disease and death, they do not block infection.
28A person can be fully vaccinated and still carry and pass the virus.
29What is needed to defeat SARS-CoV-2 is likely a new kind of vaccine that also blocks virus spread, said Dr. Gregory Poland, a vaccine developer at the Mayo Clinic.
30Until then, Poland and other experts say, the world remains easily hurt by the virus.
31I'm John Russell.
1The Delta variant of the SARS-CoV-2 virus is responsible for most cases of coronavirus infections worldwide, scientists say. The COVID-19 vaccines work well against the variant so far. Fully vaccinated people who get infected rarely require hospital stays or die from the disease, medical experts say. But scientists continue to watch Delta closely for changes. 2Delta 3The Delta variant, first identified in India in December 2020, remains the most troubling kind of SARS-CoV-2 virus. 4The World Health Organization describes Delta as a variant of concern. That means the variant can increase disease spread, cause more severe disease or reduce the effects of vaccines and treatments. 5Shane Crotty is a virus expert at the La Jolla Institute for Immunology in San Diego. He described Delta's ability to spread as a "superpower." 6Delta is able to spread more than two times faster than other SARS-CoV-2 variants, says the U.S. Centers for Disease Control and Prevention. Studies suggest it may be more likely to put infected people in the hospital than earlier forms of the virus. 7Delta also can cause symptoms two to three days sooner than the original SARS-CoV-2, giving the immune system less time to put up a defense. 8People infected with Delta carry around 1,200 times more virus in their noses compared with the first kind of the coronavirus. The amount of virus in vaccinated individuals who become infected with Delta is about the same as those who are unvaccinated. And both vaccinated and unvaccinated people can spread the virus to others. 9In vaccinated people, however, the amount of virus drops more quickly, so they likely spread the virus for a shorter time. 10The WHO says Delta makes up 99.5 percent of all genetic samples of coronavirus infection reported to public databases. 11However, in South America, where Delta has spread more slowly, other variants such as Gamma, Lambda and Mu still make up a large number of reported cases. 12Many vaccine experts predict that all future variants will develop from Delta. One such variant is known as AY.4.2. In Britain, the variant represents 10 percent of virus samples. 13The British government's health security agency has named the AY.4.2 a "Variant Under Investigation." Officials say an early study suggests the variant does not substantially reduce vaccine effectiveness in comparison to Delta. However, there is some evidence that AY.4.2 could spread more easily than the older Delta, the agency said. 14AY.4.2 has spread to at least 42 countries, including the United States. 15More on the way? 16Virus experts are closely watching the evolution of Delta. 17While current vaccines prevent severe disease and death, they do not block infection. A person can be fully vaccinated and still carry and pass the virus. 18What is needed to defeat SARS-CoV-2 is likely a new kind of vaccine that also blocks virus spread, said Dr. Gregory Poland, a vaccine developer at the Mayo Clinic. Until then, Poland and other experts say, the world remains easily hurt by the virus. 19I'm John Russell. 20Julie Steenhuysen reported on this story for Reuters. John Russell adapted it for Learning English. Caty Weaver was the editor. 21__________________________________________________ 22Words in This Story 23variant - n. different in some way from others of the same kind 24symptom - n. a change in the body or mind which indicates that a disease is present 25evolution - n. a process of change in a certain direction