Chicago ? Doctors are not following guidelines recommending flu and pneumonia vaccinations for hospitalized adults, leaving millions of elderly patients vulnerable to potentially deadly ailments, a study suggests.

Of patients aged 65 and older who were not already vaccinated, more than 95 percent were not immunized against either disease during their hospital stays, the researchers found. They analyzed medical records for 107,311 Medicare patients nationwide who were hospitalized for various ailments during 1998 and 1999.

The results, appearing in today’s Archives of Internal Medicine, suggest that millions of patients nationwide are failing to get the inoculations each year, the study says.

Combined, pneumonia and flu are the fifth leading cause of death for older Americans, killing at least 40,000 annually. Yet national data suggest that only about 50 percent of adults 65 and older have received the pneumococcal vaccine and only 65 percent get annual flu shots.

Annual flu shots are recommended for all adults aged 50 and older. Pneumococcal vaccine, recommended for adults 65 and older, is usually given once to prevent pneumonia, meningitis and bloodstream infections.

To boost vaccination rates, the government’s Advisory Committee on Immunization Practices recommends that both vaccines be administered to adults during hospitalizations. Hospitalized adults are a captive audience and are especially vulnerable to serious complications from flu or pneumonia because they’re already sick, said the lead researcher, Dr. Dale Bratzler of the Oklahoma Foundation for Medical Quality.

Bratzler said lack of awareness about the guidelines and patients’ unfounded concerns about the vaccines’ safety were partly to blame.

The Mayo Clinic in Rochester, Minn., has made the two vaccines part of a “standing orders” program, said Dr. Greg Poland, director of the Mayo Vaccine Research Group. Nurses screen every adult inpatient and vaccinate those who consent and are not already immunized, Poland said.

The study suggests far too few hospitals are doing the same, he said.

“To actually have hard numbers now that that’s how miserable this is should embarrass the medical system and hopefully outrage us and propel us to action,” Poland said.

Poland said data have shown that giving the flu vaccine to people age 65 and older can reduce by half all causes of death because influenza often weakens older people and makes them vulnerable to even more deadly ailments.

To remedy the problem, Bratzler said hospitals should make vaccination part of routine inpatient treatment by, for example, incorporating it into procedures surrounding patients’ discharge.

But doctors and nurses often have their hands full just treating a patient’s underlying ailment, said Dr. William Schaffner, a Vanderbilt University infectious diseases specialist.

Another problem is low Medicare reimbursement for vaccinations, which often doesn’t cover the cost of giving the shots, Schaffner said.