THURSDAY, Aug. 18 (HealthDay News) -- Flu vaccination levels among U.S. health care workers have risen in recent years but are still below the 2020 national health objectives, a new study says.

Researchers from the U.S. Centers for Disease Control and Prevention also found that too few moms-to-be are getting flu vaccinations.

All health care personnel should get an annual flu vaccination, according to recommendations from the Healthcare Infection Control Practices Advisory Committee and the Advisory Committee on Immunization Practices.

But this study found that fewer than two-thirds of health care personnel had a flu vaccination in the 2010-2011 flu season.

Flu vaccination was reported by only 63.5 percent of 1,931 health care personnel who took part in a national survey in April 2011. Coverage was 84 percent among doctors and 70 percent among nurses.

Flu vaccination was nearly universal among health care personnel (HCP) whose employers required staff to get vaccinated. Higher rates of vaccination were also seen in workplaces that offered free vaccinations to employees on multiple days.

"Influenza vaccination coverage among HCP is important for patient safety, and health care administrators should make vaccination readily accessible to all HCP as an important part of any comprehensive infection control program," the researchers concluded.

The study is published Aug. 18 in the CDC's Morbidity and Mortality Weekly Report.

Another study in the same issue found that flu vaccination levels among pregnant women in the United States are at historically low levels.

Pregnant women are at increased risk for influenza-related illness and death. Influenza vaccination protects pregnant women and their infants, especially those younger than 6 months old who are not old enough to receive a flu vaccination.

Despite the importance of flu vaccination, only about half of pregnant women in the United States were vaccinated during the 2009-2010 flu season, and that low level was repeated in the 2010-2011 season (49 percent).

Women who were offered an influenza vaccination by a health care provider were five times more likely to be vaccinated than those who didn't receive such an offer, the researchers said.

However, 40 percent of the women in the study didn't receive an influenza vaccination offer from a health care provider.

"Health care providers need to strongly recommend and offer inactivated influenza vaccination to their pregnant patients. Vaccinating pregnant women against influenza protects both women and their infants," the researchers concluded.

More information

The March of Dimes has more about flu and pregnancy.