More flu shots will be produced this upcoming influenza season, as health officials are urging every American to get the vaccine though the strain of flu remains unchanged since the 2010 to 2011 flu season.

The U.S. Centers for Disease Control and Prevention on Thursday once again recommended that everyone over the age of 6 months get the flu shot, even if they got it last year.

Annual vaccination is recommended including people who were vaccinated last year, said Dr. Carolyn Bridges, associate director for adult immunization, Immunization Services Division in our National Center for Immunization and Respiratory Diseases during a telebriefing on Thursday.

She said this is because levels of protective antibodies against influenza viruses decline over the course of the year, particularly in elderly and people with compromised immune systems, and other people who may be susceptible to complications of flu.

So even people that got a flu vaccine last year should get vaccinated again this year to ensure that they are optimally protected, Bridges said.

This year's vaccine protects against H1N1, or swine flu, and two other flu strains namely H3N2 and influenza B.

CDC anticipates that an estimated 166 million doses of the flu vaccine will be produced this year, which is more than the 157 million doses distributed last year.

The influenza vaccination of health-care personnel has increased slowly over the past decade, Bridges said, adding that for this past season it reached 63.5 percent. It was 62 percent last season.

But coverage is well below the healthy people 2020 goal of 90 percent, she added.

Coverage was highest amongst physicians, among health-care personnel who worked in hospital settings, and among those who are 60 years of age and older, Bridges said. Among the 13 percent of surveyed health-care personnel who have reported that their workplace required influenza vaccination, 98 percent were vaccinated.

She added that among the remaining health-care personnel surveyed who didn't report having a workplace requirement, coverage was 58 percent. In the absence of a workplace requirement, higher vaccination coverage was associated with vaccine being offered on site at the workplace, being offered free of charge, and being offered more than one day, she said.

Offering vaccines in the work site was particularly important; coverage was 66 percent among health-care personnel who were offered vaccine at the workplace versus 38.5 percent among those not offered at the workplace, according to Bridges. And this is among health-care personnel who did not have a workplace requirement. Making vaccination convenient for health-care personnel is a key strategy for raising vaccination rates.

The CDC is also encouraging pregnant women to ensure they get the flu vaccine, as they are known to be at higher risk of severe illness from the flu.

Vaccination during pregnancy has been shown to decrease the risk of illness in the mother as well as to decrease of the risk of influenza and influenza hospitalization in their infants during the first six months of life, Bridges said. This is important because children under 6 months of age are the pediatric group at highest risk of flu-related hospitalization, but they are not old enough to get vaccinated.

The Aug. 18 issue of the CDC's Morbidity and Mortality Weekly Report estimates that the influenza vaccine coverage among pregnant women for the 2010 to 2011and found that 49 percent of pregnant women had received influenza vaccination; 32 percent during pregnancy and 17 percent before pregnancy or after delivery.

The overall coverage of 49 percent was comparable to the coverage for 2009 to 2010 during the pandemic year, Bridges said.