Only 12 percent of teenagers in the United States got a meningitis shot recommended by U.S. health officials, according to a government survey released Thursday.
And only 11 percent got another relatively new shot, one that guards against tetanus, diphtheria and whooping cough. Health officials said they were not alarmed, however, because the two shots only came on the market in 2005.
Health officials say children should get both shots when they are 11 or 12.
While bacterial meningitis is rare, it can be deadly and is easily spread within schools and dormitories. The new vaccine was in short supply at first, so many students had difficulty getting vaccinated. But officials say the supply has stabilized.
Doctors with the U.S. Centers for Disease Control and Prevention said the surveys were the first to measure vaccination rates for shots aimed specifically at teenagers, and they will use the results as a baseline for future comparisons.
"The good news is we now have a way to measure coverage in this age group," said Dr. Melinda Wharton, deputy director of the CDC's National Center for Immunization and Respiratory Diseases.
Researchers conducted household telephone surveys from October to February, and verified vaccinations through medical records. The study's results include nearly 3,000 adolescents ages 13 to 17.
The survey did not include the new HPV vaccine, which prevents a virus that causes cervical cancer, because that vaccine was just recommended by the CDC in March.
Vaccination rates were 70 percent to 90 percent for shots guarding against chickenpox, hepatitis B and measles, mumps and rubella, the study found. But those shots have been available for years and are required in most states before children are allowed to attend grade school.
"That's not true of these newer vaccines" aimed at teenagers, said Dr. Daniel Blumenthal, professor of community health and preventive medicine at Atlanta's Morehouse School of Medicine.
In a second study released Thursday, researchers found a slight increase in vaccination rates last year for very young children, for ages 19 months through 35 months.
The results were based on a national telephone survey of the families of 21,000 children. The study found 77 percent had received all six recommended shots for that age group, just slightly higher than the 2005 rate.
Massachusetts has the highest vaccination level, at 84 percent, and Nevada has the lowest at 59.5 percent.