Public health officials, although not predicting a flu epidemic this year, are advising persons in the "high risk" category to be vaccinated now against influenza.

These officials say that the elderly and persons with a variety of chronic ailments should protect themselves against influenza, bacterial pneumonia and resulting complications. But, still mindful of the swine flu fiasco six years ago, they are not recommending vaccinations for the population as a whole.

Alaskan health officials have reported an outbreak -- a higher than average occurrence -- of A Bangkok flu. A Bangkok, A Brazil and B Singapore were the most prevalent influenzas last year, and they are expected to be around again this season as well. The vaccine being administered acts against all three types.

According to Dr. Karl D. Kappus, an epidemiologist in the flu branch of the Centers for Disease Control in Atlanta, no major new strains of flu have been spotted this year.

Health officials vary in their predictions of how severe this flu season will be, after last year's relatively mild experience.

In 1975-76, health officials advocated a mass inoculation campaign to ward off what they predicted would be a severe epidemic of swine flu. Although the epidemic never materialized, millions of Americans were inoculated against swine flu. One person died of swine flu, but 120 died from reactions associated with the flu shots they received.

Partially as a result of that experience, health officials have taken a more cautious approach to influenza inoculations. Dr. Richard J. Duma, president of the National Foundation for Infectious Diseases, specifically rejected the idea that persons who are not "at risk" should be vaccinated as part of a mass campaign.

Dr. Sidney Wolfe, director of the Health Research Group, supported inoculations for high-risk individuals but said it was a "bad idea" to try to inoculate the general population. Wolfe said influenza vaccines are among the "less effective" of vaccines. Duma said flu vaccines are 70 percent effective in preventing influenza.

Although most persons who get the flu recover from it within a week to 10 days, thousands die from it, or a combination of flu and pneumonia, every year. In 1980-81, according to the CDC, between 60,000 and 70,000 persons died from one or both of the diseases.

In addition to the elderly -- defined as those 65 or older -- persons with chronic ailments (including heart disease, kidney disease, diabetes and alcoholism), respiratory problems, sickle cell anemia, transplant recipients, persons taking steroids and persons in chronic-care facilities should receive the vaccination, according to the National Foundation for Infectious Diseases.