ANNAPOLIS, SEPT. 29 -- Maryland prison officials said today they fear a "whopping epidemic" of AIDS cases in the state's prisons, but added that they are encouraged by a study that shows transmission of the disease in the institutions is low.

Officials said they also don't plan any change in the state's decision not to require mandatory AIDS testing of incoming inmates, even though legislators today criticized the decision as "stupid" and called it an attempt to conceal the number of prisoners who have been exposed to the acquired immune deficiency syndrome virus.

"I'm not hiding anything," said Arnold J. Hopkins, commissioner of the state Division of Correction.

Dr. Thomas Brewer, chief medical officer for the division, said there are only two confirmed cases of AIDS among about 14,000 inmates now in the Maryland prison system, but warned that more cases are inevitable.

"The horror stories are true," Brewer told a Senate Budget and Taxation subcommittee that oversees the corrections system. "We're going to see a whopping epidemic."

Brewer said that a recently completed study, the full results of which will soon be published in the Journal of the American Medical Association, showed that 7 percent of the men and 15 percent of the women entering prison had been exposed to the AIDS virus. The study tested about one-quarter of the inmates entering prison in each of the last three years, he said.

"That's why I say there's an epidemic on the way," Brewer said after the meeting. "We're not sure why we haven't seen it yet."

Brewer said it was impossible to predict how many of those exposed to the virus would later develop AIDS, but said he would not be surprised to eventually see 30 cases a year in the prison system.

The study's retesting of those who entered prison without signs of the virus showed that less than 1 percent had been exposed to it in prison.

Hopkins and Brewer said they found the retesting encouraging. "I was afraid it would be much, much higher," Hopkins said.

But legislators were not as pleased. "I think it's a significant amount of transmission," said Sen. Julian Lapides (D-Baltimore). He said extrapolation indicates that about 70 inmates have been exposed to the virus since entering prison.

Lapides and others criticized the prison officials for not testing all incoming inmates for exposure to the AIDS virus. "I can't believe what I'm hearing," said Sen. John A. Cade (R-Anne Arundel).

Brewer said the Correction Division is following a policy set by the governor's advisory commission on AIDS in not requiring mandatory testing and said it would be expensive to test all inmates. He said prison officials already treat each prisoner as if he has been exposed to the disease.

"I think it's absolutely essential" to know how many of the inmates have been exposed to the virus, Lapides said. "I don't know whose policy it is, but it's a stupid one."

Sen. Charles Smelser (D-Frederick) said he supported mandatory testing to get treatment for afflicted prisoners and to "protect society" when inmates are released.