For the first time, doctors early next year will be able to immunize people against a major kind of pneumonia.

A new vaccine is proving nearly 80 per cent effective in preventing this disease's most common form - pneumonia caused by pneumococcus bacteria.

The vaccine will be licensed late this year, it is expected, for initial use mainly in the two groups most susceptible to this common lung disorder: those over 50 and those with heart and lung problems, diabetes and other chronic illnesses.

Among its successes, however, the vaccine has shown its ability to reduce the incidence of pnuemonia in another highly vulnerable group - children and young adults with sickle cell anemia.

One black in 400 has this often fatal or crippling disorder. The vaccine's use in one of the first advances in its treatment despite fervent efforts in the last five years.

These advances against pneumonia caused by pneumococcus bacteria were reported yesterday by the National Institutes of Health, the Bureau of Biologics, which licenses vaccines and doctors at the University of California at San Francisco who conducted the sickle cell disease tests.

Perhaps half of the 2.8 million cases of pneumonia in the United States each year are caused by bacteria, the rest by viruses or another class of organism called mycoplasma. Of the bacteria, the pneumococci - tiny oval or sphere-shaped disease organisms -are by far the most common.

Despite use of penicillin and other antibiotics, pneumococcal pneumonia is still fatal in at least one patient in 20, and often far more. According to an editorial in today's issue of the New England Journal of Medicine, the death rate was 17 per cent in one closely studied group of patients, and 27 to 28 per cent among people 50 and older and among the chronically ill.

There are some 500,000 cases of pneumococcal pneumonia in the United States each year estimates teh editorial's author, Dr. Robert Austrian of the University of Pennsylvania. Calculating deaths at a conservative 5 per cent, this would mean 25,000 people die from the disease each year.

In 1967, N'H's National Institute of Allergy and Infectious Diseases started a program to develop a pneumococcus vaccine. Eighty-four types of pneumococci have been identified since, and a vaccine against the 14 most common ones has proved 72 to 82 per cent effective in trials.

Among these was a trial among 12,000 South African gold miners, who are highly susceptible to the disease when they leave their homes to work in the mines.

Similar trials have been conducted among 14,900 Americans, including some trials in progress at Kaiser Permanente Medical Center in San Francisco and Dorothea Dix Hospital in Raleigh N.C.

Though all results are not yet in, Austrian - one of the vaccine's leading developers - says the vaccine has been proving "safe and effective."

It has caused no recorded deaths. But 35 to 40 per cent of those immunized have temporary pain of discomfort and swelling, and 3.4 per cent have elevated temperatures. Until health officials are more certain of the vaccine's safety - and this may take many thousands of immunizations - use will be limited to those with the highest risk of fatal pneumonia.

This might include those in schools, military installations, industries, Indian reservations and other crowded places where pneumonia is often epidemic.

In the two-year test in sickle cell disease patients aged 2 to 25, there was no pneumonia in 77 immunized individuals. There were eight cases in the same period in 106 unimmunized sickle cell patients.

The vaccine the Bureau of Biologics expects to license has been developed at Merck, Sharp & Dohme Research Laboratories in West Point Pa., Under Dr. Maurice Hilleman, a leader in immunization.