It's a matter of the risks versus the benefits.

A lot of things in life are a gamble. Only nobody wants to gamble with their baby's life.

Channel 4's recent program on the pertussis vaccine dealt at length with the risks of the anti-whooping cough shot. Pertussis is the "P" in the DPT shot, the three-pronged protection against diphtheria, whooping cough and tetanus. The program, the result of a year-long investigation, was shown several times, prompted several news programs, including a national bit on NBC's "Today" show, and drew some 2,000 viewer calls.

Finally, the program drew the virtually unanimous condemnation of the nation's prestigious American Academy of Pediatrics, the National Centers for Disease Control, the Bureau of Biologics of the Food and Drug Administration and the director of the Children's Hospital National Medical Center, among others.

Mainly, the critics say, the program did not weigh risk against benefit. And it exaggerated the risks.

They point to the smallpox experience. When side effects associated with smallpox vaccine were occurring with greater frequency than the incidence of smallpox itself, pediatricians stopped giving children smallpox vaccinations. If smallpox, now considered to be effectively wiped from the face of the earth, should recur in force, you can bet that parents will be rushing their children into doctors' offices for the vaccinations.

The program on pertussis suggested that "serious" complications of the vaccine could occur once in every 700 children, outweighing the benefits. The medical community is suggesting now that it may be as rare as once in every 100,000, probably less.

The truth probably lies somewhere in the middle, depending on what you term "serious." Many children run a fever, are fretful and altogether unhappy after one or another of the shots. Pediatricians generally warn parents about this, although often not until after the shot has been administered. Some children may run a very high fever: 105 or more. Others may suffer a one-time convulsion, even a grand mal seizure or a period of screechy crying quite distinctive from the baby's usual crying. In cases most pediatricians consider exceedingly rare, a child may suffer permanent brain damage as a result of the pertussis vaccine.

Pediatricians, microbiologists and neurologists are aware that the pertussis vaccine is what they call "reactive." They would prefer a purified vaccine where there are no risks, but although one may be close, no such vaccine so far has been proven successful in preventing the illness. And the illness needs to be prevented.

Pertussis is caused by a bacillus--a rod-shaped bacterium--that does its dirty work in two ways:

* It sticks to the sensitive cilia in the respiratory tract, causing the persistent, sometimes months-long cough characterized by the whoop, the gaspy intake of breath, during which breathing can stop for seconds at a time.

* It produces toxins which themselves can cause permanent neurological damage in pertussis patients at a much greater rate--probably more than 10 times--than is caused by the vaccine. Moreover, in infants under five months, there is a high fatality rate: perhaps one-third.

It is true that to a point, whooping cough can be better and more successfully treated today than in the pre-vaccine era, at least in very early stages when antibiotics may be effective.

Opponents of the vaccine also maintain that the decline of pertussis incidence was not due completely to the vaccine, but to better hygiene and nutrition. However, in countries where vaccine usage has dropped off--either because of concern for the reactions or because for some reason it was not effective--there has been a resurgence of whooping cough, contrary to assertions in the program.

For example, according to information from the FDA's Bureau of Biologics (B.O.B) Sweden had 8,000 pertussis cases in 1980 after a vaccine found to be ineffective was discontinued. Dr. John Robbins, director of the Division of Bacterial Products at B.O.B. notes that if these figures were projected for the U.S. it would mean 250,000 cases, which, he says, "The Bureau of Biologics considers an epidemic."

In Great Britain, where the vaccine was made voluntary because of an outcry against side effects, cases soared from about 25,000 in 1974-75 to almost 100,000 in 1977-78. British authorities, says Robbins, now have written every pediatrician in the U.K. urging them to convince their patients to have the shot.

Lea Thompson, Channel 4's respected investigative reporter/producer who is responsible for the program, says she did not intend to panic parents into rejecting the shot, only to spotlight facts about its dangers, facts she believes have been "suppressed by the medical establishment." Whether this was to protect doctors from lawsuits, or out of genuine concern about epidemics of whooping cough, Thompson believes an earlier outcry would have produced a safer vaccine long ago.

Indeed, physicians may well suspect that if a parent were told that a baby had one chance in 100,000 (or even a million) of permanent brain damage to prevent an illness that nobody can remember anybody having, many--perhaps most--parents would reject the shot.

Consent forms, usually required at state and municipal health centers where shots are given, discuss the benefits and the risks. The forms are used rarely in private offices.

Some countries have protected physicians from suits by establishing compensation boards for complications resulting from medical treatment required by law, a program endorsed for this country by the American Academy of Pediatrics.

The TV special had many shortcomings, including a tone described most often as "hysterical." Nevertheless, the dialogue has begun.