LONDON, JAN. 27 -- The U.S. government plans to mail an informational brochure about AIDS to all American households later this year, a top official in the U.S. Department of Health and Human Services announced today.

Assistant Health Secretary Robert E. Windom did not describe the brochure in his speech to a global AIDS conference here. But other U.S. officials said it would probably discuss how the deadly virus is transmitted, the importance of abstinence from sex before marriage and faithfulness thereafter, and the use of condoms.

"We are continuing to expand our national information campaign with a national household mailing scheduled for midyear," Windom told senior health officers and government ministers from 146 countries attending the conference.

The mailing was authorized by Congress last year, but there had been little indication of its timing.

Dr. Gary Noble, deputy director for AIDS at the Centers for Disease Control in Atlanta, told reporters earlier in the day that research is being conducted in small and large cities throughout the United States "to find out exactly what information is needed."

The AIDS brochure will probably address "risk behavior, sex, sexual transmission, HIV {the AIDS virus}, drug transmission, the importance of abstinence before marriage and faithfulness after marriage, and for those who are unable or unwilling to follow this advice, {the need} to use condoms properly," he said. He said the brochure would go to every U.S. household.

Separately, U.S. Surgeon General C. Everett Koop told reporters he predicts more American heterosexuals will become infected with AIDS, but said the United States probably will not face an explosion of cases among heterosexuals.

Koop said the prevalence of the AIDS virus among heterosexuals makes it "quite evident" that the incidence of the disease in that group will rise from the current 4 percent attributed to heterosexual intercourse.

An estimated 70-80 percent of AIDS cases reported in the United States and Europe have been among male homosexuals, but in parts of Africa and the Caribbean the disease is striking men and women in roughly equal numbers, according to the World Health Organization.

Asked about programs in some European countries to give drug users sterile needles in hopes of slowing the spread of AIDS, Koop said, "With a fatal epidemic that's spreading as this one is, you do anything in the world that you can do to stop it. And if providing free needles will stop it, that's fine."