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IMMUNE SYSTEMS: INJECTING VACCINES
The technique of injecting children with vaccines made from weakened viruses has reduced measles, mumps, and rubella (German measles) to only a few thousand cases of each a year, the lowest levels in history. (The rubella vaccine is critical for any woman of childbearing age because, if she becomes pregnant, the virus can blind, deafen, or retard her unborn child.)
Despite these successes, vaccine science is not without controversy over the relative safety of live versus killed viruses and bacteria.
Those who favor live vaccines point with pride to the success of the live Sabin polio vaccine (named for Dr. Albert Sabin), which practically wiped out polio. Made from thoroughly enfeebled, but live, viruses, it is touted today as one of the safest of the live vaccines. Nevertheless, it causes 5 to 10 cases of paralysis in the United States each year. Although it protects the vaccinated person from disease, the virus in the vaccine somehow regains its strength and may contaminate others.
Dr. Salk and other proponents of his killed virus vaccine say that it is safer than and just as potent as the live Sabin vaccine. They point to another vaccine, DTP, a single vaccine that contains no living matter yet has all but obliterated three long-feared childhood diseases: diphtheria, tetanus, and whooping cough, also called pertussis. (These three infections are caused by bacteria. Bacteria are perhaps a hundred times larger than viruses, and, unlike viruses, they can reproduce outside cells. They do their damage by emitting poisons.)
But even vaccines made from killed viruses and bacteria are not without problems. From a controlled British study, it has been determined that the DTP vaccine causes brain damage in one child in 310,000. Nevertheless, without vaccination, the incidence of death by whooping cough increases by 19 times, and the likelihood of brain damage quadruples. So, its advocates insist, taking the vaccine is much safer than not taking it.
In response to the need for new vaccines – and questions about existing ones -the National Institute of Allergy and Infectious Diseases has set up a priority list of 10 inoculations against serious germ maladies. High on that list are finding a new, safer vaccine for whooping cough and winning approval from the Food and Drug Administration for the chicken pox vaccine.
The institute also advocates a live vaccine for influenza, which kills 10,000 people a year.
Several vaccines made from killed influenza virus already exist. They particularly benefit older, chronically ill people who have lung, heart, and other health infirmities. But only 20 percent of this high-risk group takes the shots. If all such high-risk people were inoculated, says the Center for Disease Control in Atlanta, flu vaccines could save an additional 5,000 lives in the United States.
But because the flu plays tricks on scientists, the influenza virus presents its own special, problem. With each flu season, several different viruses may circulate in the population, so that the old vaccine doesn’t work. Health officials hope that a live vaccine will be easier to manufacture and administer than a killed one. For one thing, if a new flu virus appears on the scene, scientists can quickly tailor-make a vaccine to stop that epidemic. For another, the new vaccines may be sprayed into the nose. Researchers believe that people may be more willing to inhale a vaccine than to take shots.
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