WASHINGTON - C. Everett Koop, the surgeon general who gave the country its first frank talk about AIDS almost 25 years ago, warned Wednesday that the disease is becoming 'the forgotten epidemic.' About 56,000 Americans become infected each year, about 15,000 die and about one-fifth of those with the virus don't know they have it, he told a gathering at the National Press Club. HIV - the virus that causes AIDS - continues to be transmitted readily in the gay community, and efforts to prevent infections or diagnose them early have not made much progress. 'Simply put, HIV is no longer on the public's radar screen, and the result is deadly serious,' Koop said. Although ignorance about AIDS remains widespread, the 'irrational fear' that accompanied its emergence in the early 1980s has now been replaced by 'a growing sense of complacency that is as dangerous,' he added. Koop, who is 95 and lives in New Hampshire, is in Washington to attend the National Summit on HIV Diagnosis, Prevention and Access to Care. He will give an address on Friday about his experiences in the early days of the AIDS epidemic and will receive an award. At the news conference, Koop spoke from a wheelchair, his head bent forward close to his text. He told the gathering that he is 'very, very deaf' and in the past few months had become legally blind. 'I suspect this is probably the last time I'll be speaking in the National Press Club,' he said. Appointed by President Ronald Reagan in 1981 - the year AIDS was first described - Koop was an unexpected vehicle for AIDS education and advice on safe-sex practices. He was a pediatric surgeon, not a public health physician. He was a practicing Christian who wrote theological tracts. Unlike recent holders of the office, he always wore his surgeon general's dress uniform, which with his mustacheless beard made him look like an admiral from the Civil War. Koop became famous for frank, practical and nonjudgmental talk about AIDS. In 1986, he issued a report to the American people about the disease, with 20 million copies distributed to local governments, schools and physicians. In 1988, an eight-page version was mailed to 107 million households, which he recalled being told was the largest mass mailing in U.S. history. In the early years of the epidemic 'the country was rife with rumors and misinformation' that HIV could be contracted through casual contact at schools, restaurants and in bathrooms, he said. There was also 'a pervasive bias against the people most affected by HIV/AIDS, which severely hampered our ability to respond,' he added. In his public pronouncements, he said he focused on two messages: that the risk of infection increases with the number of sexual partners and that the best protection besides abstinence is the use of condoms. The unchecked expansion of the epidemic slowed as that message sank in. 'What was the lesson here?' Koop asked. 'If you tell people the truth, in a very factual way, they will act. When it comes to bad news or controversial issues, Americans want to hear it straight.' While HIV infection remains concentrated in the gay community - 53 percent of new cases are in gay and bisexual men - almost half of the people who are infected are black, which is far different from the white, middle-class first face of the epidemic. Gay men in the 1980s altered their behavior, but a generation later 'a whole new cohort moved from adolescence into adulthood totally untaught,' Koop said. Prevention efforts should be aimed at gays, bisexuals and intravenous drug users, as in the early years, and also at African Americans, who account for half of the people with HIV, and Hispanics, a population group with rising rates of infection. Koop appeared with three AIDS scientists and public health physicians, who previewed what they would say at the HIV summit, being held at National Harbor in Maryland. He was asked to give the final message at the news conference. 'I occasionally get birthday cards that say, 'Never, never, never, never give up,' ' he said. 'That's my message.' 