Researchers Explore Improvements to COVID Vaccines
2022-04-27
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1Drug companies are testing new methods to improve the efficacy of COVID-19 vaccines, using combination shots or nasal drops.
2They hope the continued research will help strengthen resistance to a continuously changing coronavirus.
3The first COVID-19 vaccines remain protective against serious sickness, hospitalization and death, especially after a booster dose.
4However, drug companies are facing growing pressure to develop vaccines better at fighting off milder infections.
5Updating vaccines to match the latest variants is risky, because future variants could be very different.
6So, companies are considering something like a flu vaccine, which offers protection against three or four different strains in one shot every year.
7Moderna and Pfizer are testing 2-in-1 COVID-19 protection that they hope to offer this fall.
8Each "bivalent" shot would mix the original, proven vaccine with an omicron-targeted version.
9Moderna has some early evidence that the idea could work.
10It tested a combination shot that targeted the original version of the virus and an earlier variant named beta.
11It found vaccine recipients developed limited levels of antibodies capable of fighting not just beta but also newer variants like omicron.
12Moderna now is testing its omicron-targeted bivalent candidate.
13Dr. David Kimberlin, a CDC adviser from the University of Alabama at Birmingham, recently suggested that for the average person, two doses of the Pfizer or Moderna vaccine plus one booster - a total of three shots - "gets you set up" and ready for what may become a yearly booster.
14After that first booster, CDC data suggests an additional dose offers most people a small, temporary benefit.
15Experts recommend three shots because vaccination triggers development of antibodies that can fight off coronavirus infection.
16Such antibody levels naturally decrease over time.
17But memory cells jump into action to make new virus-fighters if an infection sneaks in.
18Rockefeller University researchers found those memory cells may become stronger and able to target more diverse kinds of the virus after the third shot.
19Even if someone who is vaccinated gets a mild infection, memory cells still help give "time to protect you against severe illness," said Dr. Paul Offit of the Children's Hospital of Philadelphia.
20But some people - those with severely weakened immune systems - need more doses early on for a better chance of protection.
21Americans 50 and older are being offered a second booster, following similar decisions by Israel and other countries that offer the extra shot to give older people a little more protection.
22The CDC is developing advice to help those eligible decide whether to get an extra shot now or wait.
23Among those who might want a second booster sooner are the elderly, people with health problems or people who are at high risk of exposure from work or travel.
24It is hard for a shot in the arm to form lots of virus-fighting antibodies inside the nose where the coronavirus latches on. But a nasal vaccine might offer a new way to prevent infections.
25"When I think about what would make me get a second booster, I actually would want to prevent infection," said Dr. Grace Lee of Stanford University, who chairs CDC's immunization advisory committee. "I think we need to do better."
26Nasal vaccines are difficult to develop, and it is not clear how quickly any could become available.
27But several are in clinical trials around the world.
28One in late-stage testing, made by India's Bharat Biotech, uses a chimpanzee cold virus to deliver a harmless copy of the coronavirus spike protein to the lining of the nose.
29"I certainly do not want to abandon the success we have had" with COVID-19 shots, said Dr. Michael Diamond of Washington University in St. Louis. Diamond helped create the candidate that is now licensed to Bharat.
30But "we're going to have a difficult time stopping transmission with the current ... vaccines," Diamond added.
31"We have all learned that."
32I'm John Russell.
1Drug companies are testing new methods to improve the efficacy of COVID-19 vaccines, using combination shots or nasal drops. They hope the continued research will help strengthen resistance to a continuously changing coronavirus. 2Original vaccines and "bivalent" vaccines 3The first COVID-19 vaccines remain protective against serious sickness, hospitalization and death, especially after a booster dose. 4However, drug companies are facing growing pressure to develop vaccines better at fighting off milder infections. 5Updating vaccines to match the latest variants is risky, because future variants could be very different. So, companies are considering something like a flu vaccine, which offers protection against three or four different strains in one shot every year. 6Moderna and Pfizer are testing 2-in-1 COVID-19 protection that they hope to offer this fall. Each "bivalent" shot would mix the original, proven vaccine with an omicron-targeted version. 7Moderna has some early evidence that the idea could work. It tested a combination shot that targeted the original version of the virus and an earlier variant named beta. It found vaccine recipients developed limited levels of antibodies capable of fighting not just beta but also newer variants like omicron. Moderna now is testing its omicron-targeted bivalent candidate. 8Boosters 9Dr. David Kimberlin, a CDC adviser from the University of Alabama at Birmingham, recently suggested that for the average person, two doses of the Pfizer or Moderna vaccine plus one booster - a total of three shots - "gets you set up" and ready for what may become a yearly booster. 10After that first booster, CDC data suggests an additional dose offers most people a small, temporary benefit. 11Experts recommend three shots because vaccination triggers development of antibodies that can fight off coronavirus infection. Such antibody levels naturally decrease over time. 12But memory cells jump into action to make new virus-fighters if an infection sneaks in. Rockefeller University researchers found those memory cells may become stronger and able to target more diverse kinds of the virus after the third shot. 13Even if someone who is vaccinated gets a mild infection, memory cells still help give "time to protect you against severe illness," said Dr. Paul Offit of the Children's Hospital of Philadelphia. 14But some people - those with severely weakened immune systems - need more doses early on for a better chance of protection. 15Americans 50 and older are being offered a second booster, following similar decisions by Israel and other countries that offer the extra shot to give older people a little more protection. 16The CDC is developing advice to help those eligible decide whether to get an extra shot now or wait. Among those who might want a second booster sooner are the elderly, people with health problems or people who are at high risk of exposure from work or travel. 17Nasal vaccines 18It is hard for a shot in the arm to form lots of virus-fighting antibodies inside the nose where the coronavirus latches on. But a nasal vaccine might offer a new way to prevent infections. 19"When I think about what would make me get a second booster, I actually would want to prevent infection," said Dr. Grace Lee of Stanford University, who chairs CDC's immunization advisory committee. "I think we need to do better." 20Nasal vaccines are difficult to develop, and it is not clear how quickly any could become available. But several are in clinical trials around the world. One in late-stage testing, made by India's Bharat Biotech, uses a chimpanzee cold virus to deliver a harmless copy of the coronavirus spike protein to the lining of the nose. 21"I certainly do not want to abandon the success we have had" with COVID-19 shots, said Dr. Michael Diamond of Washington University in St. Louis. Diamond helped create the candidate that is now licensed to Bharat. 22But "we're going to have a difficult time stopping transmission with the current ... vaccines," Diamond added. "We have all learned that." 23I'm John Russell. 24Lauran Neergaard reported on this story for the Associated Press. John Russell adapted it for Learning English. 25________________________________________________________________________ 26Words in This Story 27nasal - adj. of or relating to the nose 28variant - n. different in some way from others of the same kind 29antibody - n. medical : a substance produced by the body to fight disease 30benefit - n. a good or helpful result or effect 31eligible - adj. able to do or receive something