Do Old Vaccines Help Protect Against COVID-19?
2020-04-18
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1Scientists want to find out if vaccines already in existence might provide protection against COVID-19.
2The idea does not seem to make sense. Vaccines are designed to target a single virus or bacterium.
3But vaccines made using active strains of bacteria or viruses seem to help the body's natural defenses, called the immune system, fight non-targeted diseases as well.
4There is no evidence yet that such vaccines could improve the immune system enough to resist the new coronavirus.
5But, a COVID-19 vaccine is expected to take 12 to 18 months.
6So, some researchers say it is time to test a tuberculosis vaccine for possible effects on the new coronavirus.
7Dr. Mihai Netea is with Radboud University Medical Center in the Netherlands.
8He says if the TB vaccine works, "it could be a very important tool to bridge this dangerous period" until a COVID-19 vaccine is available.
9The World Health Organization on Monday strongly warned against the use of the tuberculosis vaccine against COVID-19 until studies prove it works.
10Netea's team is leading such a study already involving almost 1,500 Dutch health care workers as subjects.
11The researchers are treating some of the workers with the TB vaccine called BCG.
12It is made of a live but weakened bacterium related to TB bacteria.
13The other study subjects are treated with a placebo, an inactive substance.
14Another study of BCG is taking place with 4,000 hospital workers in Australia.
15Similar research is being planned in other countries, including the United States.
16Another possibility for treatment is a polio vaccine made of live but weakened polio viruses.
17The Global Virus Network in Baltimore, Maryland wants to begin studies with that vaccine, which is taken by mouth.
18Dr. Robert Gallo, a founder of the group, told The Associated Press that he is discussing the idea with health officials.
19Jennifer Routh of the U.S. National Institutes of Health also said researchers there are discussing TB and polio vaccines as a possible COVID-19 defense.
20Live vaccines, however, are risky for people with weakened immune systems.
21They should not be tried against COVID-19 outside of a research study, said Dr. Denise Faustman.
22She is immunobiology chief at Massachusetts General Hospital and is planning a TB vaccine study.
23She added that her study provides a good chance "to prove or disprove this off-target effect."
24Years ago, scientists began noticing that people vaccinated with some live vaccines had improved immunity to non-targeted sicknesses.
25The TB vaccine, for example, is given mostly to babies in developing countries.
26It offers only partial protection against bacterial TB.
27But studies suggested that the vaccinated babies had better survival rates and resisted lung infections better.
28In 2018, Netea's team published a more direct test.
29It showed that BCG vaccine increases immunity overall.
30In fact, it was good enough to at least partly block another virus given experimentally a month later.
31There has been a report that researchers in the former Soviet Union found that influenza cases dropped after polio vaccinations in the 1970s.
32And in 2015, Danish researchers found similar results with polio vaccinations given by liquid drops through the mouth.
33These are still used in developing countries, while the U.S. and other areas use the inactivated shot for childhood vaccines.
34The goal of a vaccine is to prepare the body to recognize a targeted health threat.
35Vaccines cause the body to make antibodies, products in the blood that fight bacteria and viruses.
36BCG appears to influence immune cells so they can more readily remove germs in general, said Netea, the Dutch researcher.
37Scientists not involved in the effort to try these vaccines against COVID-19 told the AP that such studies are worthwhile.
38I'm Mario Ritter, Jr.
1Scientists want to find out if vaccines already in existence might provide protection against COVID-19. 2The idea does not seem to make sense. Vaccines are designed to target a single virus or bacterium. But vaccines made using active strains of bacteria or viruses seem to help the body's natural defenses, called the immune system, fight non-targeted diseases as well. 3There is no evidence yet that such vaccines could improve the immune system enough to resist the new coronavirus. But, a COVID-19 vaccine is expected to take 12 to 18 months. So, some researchers say it is time to test a tuberculosis vaccine for possible effects on the new coronavirus. 4Dr. Mihai Netea is with Radboud University Medical Center in the Netherlands. He says if the TB vaccine works, "it could be a very important tool to bridge this dangerous period" until a COVID-19 vaccine is available. 5The World Health Organization on Monday strongly warned against the use of the tuberculosis vaccine against COVID-19 until studies prove it works. Netea's team is leading such a study already involving almost 1,500 Dutch health care workers as subjects. The researchers are treating some of the workers with the TB vaccine called BCG. It is made of a live but weakened bacterium related to TB bacteria. The other study subjects are treated with a placebo, an inactive substance. 6Another study of BCG is taking place with 4,000 hospital workers in Australia. Similar research is being planned in other countries, including the United States. 7Another possibility for treatment is a polio vaccine made of live but weakened polio viruses. The Global Virus Network in Baltimore, Maryland wants to begin studies with that vaccine, which is taken by mouth. Dr. Robert Gallo, a founder of the group, told The Associated Press that he is discussing the idea with health officials. 8Jennifer Routh of the U.S. National Institutes of Health also said researchers there are discussing TB and polio vaccines as a possible COVID-19 defense. 9Live vaccines, however, are risky for people with weakened immune systems. They should not be tried against COVID-19 outside of a research study, said Dr. Denise Faustman. She is immunobiology chief at Massachusetts General Hospital and is planning a TB vaccine study. 10She added that her study provides a good chance "to prove or disprove this off-target effect." 11Early evidence 12Years ago, scientists began noticing that people vaccinated with some live vaccines had improved immunity to non-targeted sicknesses. 13The TB vaccine, for example, is given mostly to babies in developing countries. It offers only partial protection against bacterial TB. But studies suggested that the vaccinated babies had better survival rates and resisted lung infections better. 14In 2018, Netea's team published a more direct test. It showed that BCG vaccine increases immunity overall. In fact, it was good enough to at least partly block another virus given experimentally a month later. 15There has been a report that researchers in the former Soviet Union found that influenza cases dropped after polio vaccinations in the 1970s. 16And in 2015, Danish researchers found similar results with polio vaccinations given by liquid drops through the mouth. These are still used in developing countries, while the U.S. and other areas use the inactivated shot for childhood vaccines. 17Immunity from live vaccines 18The goal of a vaccine is to prepare the body to recognize a targeted health threat. Vaccines cause the body to make antibodies, products in the blood that fight bacteria and viruses. BCG appears to influence immune cells so they can more readily remove germs in general, said Netea, the Dutch researcher. 19Scientists not involved in the effort to try these vaccines against COVID-19 told the AP that such studies are worthwhile. 20I'm Mario Ritter, Jr. 21Lauran Neergaard reported this story for the Associated Press. Mario Ritter Jr. adapted it for VOA Learning English. Caty Weaver was the editor. 22________________________________________________________________ 23Words in This Story 24strain -n. a group of closely related living things