Gerrie Cohn stroked the arm of her 15-year-old daughter Traci, who stood before the news cameras, bright lights and reporters on Capitol Hill yesterday, clutching a stuffed monkey.

"I am here to speak for Traci, because she cannot speak for herself, nor can she dress or undress herself, wash or comb her hair, read a book or write her name," said Cohn, who lives in Rockville.

"Traci has been deprived of all of this and more, because of what I feel was, and is, enforced ignorance."

Cohn said that her daughter's brain damage was the result of the pertussis or whooping cough vaccine, although she would not discuss the medical details of the case because of ongoing litigation.

"Because I was told not to worry when Traci's temperature soared and she began a high-pitched, nonstop screaming, I tried not to worry," said Cohn.

"I, like so many mothers, lacked the information necessary to even ask intelligent questions . . . . Instead I trusted the experts."

Yesterday's news conference was organized by the Dissatisfied Parents Together and the Advocates for a Safer Vaccine, who charge that the mass, mandatory use of the current pertussis vaccine in the United States is dangerous.

The Centers for Disease Control, a federal agency in Atlanta, says the benefits of the vaccine far outweigh the problems.

The pertussis vaccine, developed in the mid-1930s and widely used since the '50s, is given routinely to 96 percent of children before the age of 7 as part of the combination diphtheria, pertussis and tetanus -- or DPT -- shot.

The parents' groups said documents they released yesterday show that drug manufacturers were aware of inadequacies in the safety tests for DPT as long as 20 years ago.

They also called for a congressional investigation and tougher federal regulations for vaccines.

The House health and environment subcommittee will review the documents to determine whether an investigation is needed, said Rep. Gerry Sikorski (D-Minn.).

Sikorski added that the health subcommittee considers vaccine compensation legislation a "top priority" this year.

The legislation, patterned after a bill introduced last year by Sen. Paula Hawkins (R-Fla.) and Rep. Henry A. Waxman (D-Calif.), would give parents seeking redress various options. It is endorsed by the parents' groups, as well as the American Academy of Pediatrics.

The side effects of the shot range from minor discomfort near the site of the shot to serious brain damage.

However, the chances of serious long-term harm are about 1 in 310,000, according to the federal disease center.

The center also said that 457 persons would die of whooping cough yearly without the vaccine, compared to 44 under the vaccine program. The parents' groups question those figures.

Barbara Loe Fisher, a founder of Dissatisfied Parents Together and coauthor of a recently published book, "DPT: A Shot in the Dark," said that the parents' groups do not want all DPT vaccinations stopped.

Instead, she said, they want parents to be warned of the dangers, particularly to babies that might be in a high-risk category.

They also want stricter federal regulations for vaccines, and they want a safer vaccine developed. They are critical that the shot is mandatory for entry into schools in most states, including Virginia, Maryland and the District.

In all three local jurisdictions, there is an exemption for medical or religious reasons.