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Thursday, April 10, 2008

A Multitude of Vaccine Benefits, Yet Controversy Persists

By DONALD G. McNEIL Jr; From The New York Times


  • Vaccinations are among the most important health advances in history
  • Death rates for 13 diseases that can be prevented by childhood vaccinations were at all-time lows in the United States in 2007
  • Rumors persist that some immunizations, or the vaccine preservative thimerosal, cause autism

Public health experts generally agree that after clean water and flush toilets, the most important health advances in history have been vaccinations.

Shots against measles, diphtheria, whooping cough, tetanus, polio, mumps, rubella, chicken pox, flu, hepatitis and some causes of childhood meningitis, pneumonia and diarrhea have saved more lives than all the “miracle drugs” of the latter half of the 20th century — antibiotics like penicillin, antivirals like drugs to fight AIDS and flu, and so on. In addition, vaccination is one of the leading reasons that many families in the West now feel comfortable having only two or three children: they can be reasonably certain that the children will survive childhood.

According to a large historical study by the Centers for Disease Control and Prevention released in November 2007, death rates for 13 diseases that can be prevented by childhood vaccinations were at all-time lows in the United States. The study looked at hospital and death records going back to 1900 and estimated death rates before various vaccines were invented. In nine of the diseases, rates of hospitalization or death had declined more than 90 percent. For three — smallpox, diphtheria and polio — death rates had dropped by 100 percent.

In the 1930s, the United States had about 30,000 diphtheria cases a year, and 3,000 of those succumbed to the disease as gray membranes formed in their airways and eventually choked them to death. Diphtheria is now virtually unknown in the West, but in the chaos following the breakup of the former Soviet Union, vaccinations broke down, and the Red Cross estimated there were 100,000 cases and 5,000 deaths from the disease.

Smallpox vaccine is no longer given to children because the disease has been eliminated from the world, except for stocks frozen in laboratories in the United States and Russia. The smallpox vaccine also carried some risks.

Since the 1990s, vaccines have become somewhat controversial, even in the United States. As diseases have disappeared, generations have grown up without ever seeing the sickness and death they caused. At the same time, new parents are often upset as their babies receive between 20 and 30 injections before age 2 and suffer the pain and mild fever that can accompany them as routine side effects.

In addition, rumors continue to spread that some vaccines, or a mercury antifungal vaccine preservative called thimerosal that was added to vaccines, cause autism. Numerous studies have shown no link between autism and either vaccines or the preservative. An active anti-vaccine lobby, however, keeps the issue alive. The lobby is a broad tent. A few members question even whether bacteria and viruses cause disease; most seek more research into safety and greater rights to refuse vaccination.

State and city health departments, recognizing that the risk of epidemics soars when children gather daily in school, generally require parents to prove that children have been immunized before they enroll. There are some exceptions. All states allow medical exemptions for children who are immunocompromised or allergic to vaccine components. Most allow religious objections. A few allow “personal or philosophical” ones; how hard it is to get one varies by state.

Health insurers pay for most vaccines, and public clinics offer them free to the uninsured, the cost paid by the federal government under the Vaccines for Children Program of 1994. Before that time, incomplete vaccination was most common among the poor. Now it is more common for children from wealthy or middle-class families to lack some or all shots, presumably because their parents objected.

More vaccines are being developed all the time. Some are aimed at teenagers because they thwart diseases spread by sex or common in student dorms and military barracks. These include vaccines for human papillomaviruses, which cause cervical cancer; herpes; and meningococcal infections, the cause of sometimes deadly meningitis. Others, like those against flu, shingles and some bacterial toxins, are particularly aimed at older people, who have weaker immune systems and are more likely to be in hospitals or nursing homes.

Newer vaccines tend to be much more expensive than older ones, which were developed before the era of clinical trials costing hundreds of millions of dollars and before medical liability lawsuits were so common. But the cost of not vaccinating at all, as history has taught, can be very high.

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