The number of babies who have developed acquired immune deficiency syndrome (AIDS) from contaminated blood received during transfusions is much higher than has been reported, according to doctors at the federal Centers for Disease Control.

Also, Johns Hopkins University researchers reported yesterday that the number of AIDS cases in Maryland has nearly tripled in the last year, from 50 to 147. Federal officials announced yesterday the total number of AIDS cases in this country is now 10,050 and is expected to double in the next year.

"They're pretty alarming statistics," said Dr. Frank Polk, principal investigator for a Johns Hopkins study of 1,153 homosexual men in the Baltimore-Washington area.

Many of the AIDS-infected infants, such as Matthew Kozup, 2 1/2, of Herndon, are not counted by the federal government because they do not have certain ailments such as skin cancer. The ailments are required under a strict definition devised before a blood test was available to help detect the disease.

"We want people to be aware of these little victims," said Matthew's father, Steven Kozup, a computer engineer.

The Centers for Disease Control currently reports 120 cases of pediatric AIDS, 17 of them the result of blood transfusions, but federal officials said both totals are actually much higher. The American Red Cross Blood Services-Washington Region, for example, reports five cases of children who have developed AIDS from transfusions, but the federal government counts only one of these cases.

Because of concern about underreporting of AIDS, the federal government is debating whether to change the definition of what constitutes an official case, CDC doctors said.

The nontransfusion cases are children whose mothers either have AIDS or use drugs, or have sex partners who use drugs or have AIDS.

According to federal records, 135 of the 9,930 adults with AIDS developed the disease through a blood transfusion.

The number of children with AIDS "is a major health crisis, but the system is not geared to reporting for kids," said Dr. James Oleske, a Newark, N.J., pediatrician and expert on pediatric AIDS. "We're all caught up in the tremendous tragedy and we're still in the middle of the book . . . . I've never dealt with an epidemic that kills children this way."

"We know that we've underreported pediatric AIDS," said Dr. Harold Jaffe, chief of AIDS surveillance at the CDC. "We just don't know the magnitude."

AIDS is caused by a virus that destroys the body's immune system, allowing infections to develop. The illness has a high mortality rate and there is no known cure.

Few, if any, new cases should develop from blood transfusions because of a nationwide screening test that blood banks began using in March, federal officials said.

The growing number of AIDS cases is causing hospitals, doctors and blood banks to grapple with the problem of how to or whether to inform parents that their children were exposed to contaminated blood in the past.

Exposure does not necessarily mean that the disease -- which has a 69 percent mortality rate for children -- will develop.

At Children's Hospital, for example, parents of several children who received transfusions in 1982 and 1983 -- before blood donors were asked whether they were at high-risk for the disease -- were informed this spring that the Red Cross had determined their blood donors had AIDS virus in their blood.

Homosexual men, intravenous drug users and sex partners of either are at risk for developing AIDS.

The children have been tested "and no one has called back with adverse events," said Dr. Naomi Luban, director of the blood bank at Children's Hospital. The hospital is advising parents of children who received transfusions before April 1983 -- when high-risk donors were asked not to give blood -- to have their children examined by their pediatrician if they are concerned.

At Georgetown University Hospital, officials have not decided whether to tell the parents of a child who shared the same blood transfusion that sickened Matthew Kozup. The child died last year, but was not diagnosed as having AIDS.

"It's under consideration . . . whether there would be a benefit to let people know retroactively," said Dr. Milton Corn, medical director for the hospital. "For cases now, they're going to be told."

Because the disease is believed to have an incubation period of six months to five years, "By 1990, we'll know who's gotten AIDS from blood and that part of the transmission will be over," Oleske said.

Some doctors and health officials said the CDC should broaden its definition of official AIDS cases because under the current system, some parents are not told their children have AIDS.

"We're only measuring the most severe form of AIDS," said Jaffe.

To better determine how many children are affected, the federal government plans to launch pilot programs soon in New York City, Miami, northern New Jersey and a number of other areas to be selected. Authorities will count AIDS patients who don't have the physical symptoms that currently are required by the CDC.

"Now that the blood test is available, the case definition for children and adults may be broadened," Jaffe said. A new definition based on patient's blood should give a better picture of how widespread the AIDS epidemic is, he said.

Federal researchers have estimated that 500,000 to 1 million people have been infected with the AIDS virus and about 5 to 20 percent of those people will develop the disease.

In Washington, officials of Children's Hospital, George Washington University Medical Center, Georgetown University Hospital and the local Red Cross met last week to "exert some pressure on the CDC to get the definition changed," Dr. Luban said. "We're also concerned about exactly how the donors are tracked" by the Red Cross, which supplies blood to 60 area hospitals.

Dr. Paul McCurdy, director of the local Red Cross blood services, said, "We begin an investigation of potentially involved donors whenever a patient with possible transfusion-associated AIDS is reported to us."

But in the case of Matthew Kozup, the Red Cross apparently did not check donors for some months, until pressure was applied by the infant's doctors at Georgetown University Hospital and a team of CDC investigators, according to CDC officials.

"We thought that a donor investigation should be considered," said Jaffe. "For a long time, blood banks weren't doing these on their own."

Dr. Corn, of Georgetown, said he doesn't know "whether it was our honeyed words, or our table pounding" that got the Red Cross to track down the donors. Hospitals, he said, "cannot do the tracking."

The Red Cross said it would not discuss individual cases.

Oleske said that the transfusion-related AIDS cases should not be blamed on the nation's blood banks. "More people's lives have been saved by the American Red Cross' blood delivery system than who will ever die of AIDS," he said. "We have to be tempered and realize we can put blood transfusions [as a risk] behind us now."