The number of seniors vaccinated for flu and pneumococcal infections rose in most of the United States last year, but remained below the government’s target for this high-risk group, federal officials said on Thursday.

A study by the Centers for Disease Control and Prevention found that influenza vaccination coverage among those 65 and older increased in 37 states, the District of Columbia as well as Puerto Rico, Guam and the U.S. Virgin Islands in 2003.

Vaccination rates for pneumococcal disease, which is spread by bacteria that invade the lungs, were up in 34 states, D.C. and the three territories, according to the CDC, which is campaigning to increase coverage against both diseases.

Older Americans who get the flu or pneumococcal disease are at higher risk of developing pneumonia, meningitis and other potentially deadly infections. The diseases together are the fifth leading cause of death among the elderly.

Seniors in the U.S. Virgin Islands were the least likely to get vaccinated, while Minnesotans were the most likely to line up for the jabs.

Vaccination rates ranged from 34.9 percent to 80.3 percent for the flu and 31.6 percent to 73 percent for pneumococcal disease. The federal government’s target for 2010 is 90 percent coverage for both diseases among seniors.

Getting more doctors and other health-care providers to recommend the vaccinations to high-risk patients is one of the keys to achieving this goal, said Barbara Bardenheier, a CDC epidemiologist and one of the study’s authors.

The CDC also said on Thursday that flu vaccination rates for diabetes patients between the ages of 18 and 64 were above 50 percent in almost half the states last year. Diabetes increases the risk for complications from the flu.

The agency’s findings were released amid a shortage of flu shots in the United States.

Vaccine manufacturer Chiron Corp., which had been expected to supply 48 million doses to the nation, lost the license for its British vaccine plant last month, just before the traditional beginning of the annual flu season.

U.S. health officials have rounded up several million more doses but still have only about 61 million out of an anticipated 100 million for the 2004-2005 season.

They are recommending that only high-risk people - seniors, people with chronic diseases, babies, and pregnant women - get the vaccine. People who care for anyone in those groups should also be vaccinated.

“Ensuring adequate amounts of influenza vaccine is critical if vaccination rates of persons at high risk are to continue improving,” the CDC report said.

Influenza kills about 36,000 people and hospitalizes 200,000 in the United States each year. About 90 percent of the deaths occur among those 65 and older.