Студопедия

КАТЕГОРИИ:

АвтомобилиАстрономияБиологияГеографияДом и садДругие языкиДругоеИнформатикаИсторияКультураЛитератураЛогикаМатематикаМедицинаМеталлургияМеханикаОбразованиеОхрана трудаПедагогикаПолитикаПравоПсихологияРелигияРиторикаСоциологияСпортСтроительствоТехнологияТуризмФизикаФилософияФинансыХимияЧерчениеЭкологияЭкономикаЭлектроника



A COMEBACK FOR WHOOPING COUGH




When she was 5 /2 months old, Traci Cohn of Rockville, Md., developed a 104 °F fever and cried inconsolably for three days. Ever since that illness Traci, now 17, has been mentally retarded. Her family and one of her doctors believe that the fever and subsequent mental damage were the direct result of the pertussis, or whooping cough inoculations that she received in the first months of her life.

Whooping cough, named for the distinctive sound made by its victims as they gasp for air between bouts of violent coughing, was until the 1940s a major killer of children. Caused by a bacterial infection that increases the amount of mucus in the lungs, the disease sometimes results in convulsions and death. Over the past four decades, however, pertussis has been largely subdued in developed nations by mass inoculations with a vaccine made from killed pertussis bacteria. Now doctors annually pump :some 18


million doses of the vaccine into U.S. children — usually in the form of a D.P.T. shot, so called because it also provides protection against diphtheria and tetanus. Some 40 states require children to have D.P.T. inoculations before they are allowed to enter school.

Despite these efforts, the Center for Disease Control in Atlanta reports that the incidence of whooping cough is increasing; the latest figures show that the number of U.S. cases has nearly doubled in the past three years, from 1895 in 1982 to 3275 in 1985. Meanwhile, health officials are concerned that more and more parents, aware. of cases like Traci's, will refuse to allow their youngsters to be inoculated.

Minor reactions to the vaccine, such as redness and swelling, are common. Permanent brain damage, according to one study, occurs only once in about every 300000 inoculations, death even less frequently. Researchers suspect that these severe complica­tions — which can include convulsions, shock, loss of muscle control and fever — are caused by bacterial toxins. Still, most doctors insist that the shots are worth the risks. Martin Smith, president of the American Academy of Pediatrics, calculates that the chances of suffering serious damage from whooping cough are ten times .greater than having damaging side effects from the vaccine. Says Dr. Peter Patriarca of the CDC's immunization division: "There is no question that the vaccine has more side effects than any other vaccine. But it's a matter of risk vs. benefits".



However, many parents of children stricken by the vaccine complain that they were unaware of the risk. "Doctors don't sit down with parents and talk about the vaccine", says Washington Attorney Jeff Schwartz, whose daughter Julie died of apparent vaccine-related seizures at age three. "It's shocking to us that this information is not routinely provided". In other nations, fear of the vaccine's potential dangers has had tragic results. After two children died from side effects in 1974 and 1975, Japan banned use of pertussis vaccine for two months. Many parents were so alarmed that even after it was reinstated, they refused to inoculate their children. Between 1977 and 1979, as a result, 28000 Japanese children contracted whooping cough, and 93 died. (By comparison, between 1972 and 1974 Japan reported only 1024 cases and 6 deaths.) In Britain, more than 100000 cases of pertussis and 36 . deaths occurred between 1977 and 1979, after reports about side effects were broadcast on television. A similar epidemic struck in Sweden after the government decided to withdraw the vaccine. Says Swedish Pediatrician Patrick Olin, who is testing an alternative to the still banned shot: "The fact that we have no mass vaccination is the clear reason for the rapid increase".




Hit by a number of liability lawsuits, the pharmaceutical industry is acting defensively. Lederle Laboratories of Wayne, N. J., announced that it is boosting the price per shot of its vaccine to $11.40 (it was only 45 cents in 1982), holding back 8_of that amount for what company calls its "liability reserve".

Meanwhile, researchers are scrambling to purge the vaccine of its harmful effects. In its current form, pertussis vaccine is made by killing pertussis bacteria with heat or chemicals and grinding them up, toxins and all. When the resulting mixture is injected, several of the toxins stimulate an immune response that protects the recipient from attacks by live pertussis bacteria. But some of the toxins in the vaccine apparently cause the side effects as well.

Researchers in Japan have brewed what they hope is a safer vaccine by separating out the most dangerous toxins produced by the bacteria, leaving only four to stimulate the immune response. U.S. scientists at the National Institute of Health and the Public Health Service have gone one step further: they announced that they had determined the genetic code of the bacterial gene that orders production of one of the toxins. They hope to alter the gene so that it signals the production of only the part of the toxin that stimulates the immune response, then to use this partial toxin as an essential ingredient of a safe vaccine.



Until a safer vaccine is available in the U.S., the CDC has advised parents to watch carefully for these symptoms in children receiving D.P.T. shots: 1) severe allergic reaction like a rash or troubled breathing; 2) a fever of 105°F or higher within 48 hours of a shot; 3) the onset of shock, which is characterized by clamminess and a rapid pulse; 4) persistent crying that lasts for three hours or more, or unusual high-pitched cries; 5) seizures, fits or convulsions within three days of a ■ shot; 6) dulling of mental function within seven days of a shot. "If any one of these symptoms occurs", says the CDC's Patriarca, "no further doses of the vaccine should be given", and the child should be taken immediately to a doctor, clinic or hospital.


Дата добавления: 2015-02-09; просмотров: 9; Нарушение авторских прав







lektsii.com - Лекции.Ком - 2014-2021 год. (0.005 сек.) Все материалы представленные на сайте исключительно с целью ознакомления читателями и не преследуют коммерческих целей или нарушение авторских прав
Главная страница Случайная страница Контакты