Uptake of the influenza 2009 pandemic H1N1 vaccine by the American public showed a striking state-by-state variation, ranging from a high of 39% in Rhode Island to a low of 13% in Mississippi, the Centers for Disease Control and Prevention reported.
The CDC's H1N1 vaccination data, which covered the period through the end of January 2010, also showed sharp variations in vaccine uptake based on people's age and whether or not they fell into one of the initial target groups for the vaccine, the agency reported in an article in Morbidity and Mortality Weekly Report (2010;59:363–8).
Among Americans aged 6 months to 17 years, which was one of the initial target groups, vaccine coverage ranged from a high of 85% in Rhode Island to a low of 21% in Georgia. For all people in the initial target groups, uptake rates ranged from 58% in Rhode Island to 19% in Mississippi. In addition to children aged 6 months to 17 years, other initial target groups included pregnant women, health care and emergency medical personal, adults aged 18–24 years, and adults 25–64 years with high-risk medical conditions.
The wide geographic variation in vaccination rates “suggests opportunities for improvement” in future flu vaccine seasons, such as boosting the distribution of vaccine at public venues such as schools, the investigators wrote. Among four New England states that achieved especially high vaccination rates of 60% or greater among children, three states—Maine, Rhode Island, and Vermont—had statewide school vaccination campaigns that coincided with a period of high vaccine demand.
“While it is premature to conclude that this [statewide school-based vaccination campaign] is the reason for their success, I think there is a compelling story there that we'll have to evaluate more carefully,” Dr. Anne Schuchat, director of the CDC's National Center for Immunization and Respiratory Diseases, said at a press conference.
Health care personnel also showed high levels of H1N1 vaccine uptake, although the rate fell short of their uptake of seasonal flu vaccine during the period of August 2009 to January 2010. During that period, overall uptake of any influenza vaccine occurred in 64% of health care personnel, including 62% who received the seasonal flu vaccine and 37% who received the H1N1 vaccine. A total of 35% received both vaccines, the CDC reported in a second MMWR article (MMWR 2010;59:357–62).
The 64% overall flu vaccine uptake rate among health care personnel “for the first time meets the Healthy People 2010 target of 60%,” CDC staffers noted in the article.
The CDC also found that health care personnel who were subject to employer requirements for vaccination were most likely to receive a flu vaccine. Those results were based on health care personnel flu vaccination rates obtained in an Internet-based survey with 1,417 respondents.
In addition, 81% of the health care personnel surveyed believed the seasonal influenza vaccine was safe, compared with 67% who believed the H1N1 vaccine was safe. The two most commonly cited reasons for not receiving vaccine were “I don't need it” and “I may experience side effects.”
“We were very pleased that at least seasonal flu vaccine rates were higher than in prior years,” Dr. Schuchat said. “Maybe we're at a tipping point, where consumers and patients will demand that health care personnel be vaccinated and institutions [will] pay attention. We'd love to see health care facilities compete with each other and publicize” their vaccination rates.
Other findings from the CDC's survey of vaccination uptake in the general U.S. population showed median, nationwide rates for H1N1 vaccination of 22% in people aged 65 years or older, 14% in those aged 25–64 years and not in an initial target group, and 25% in those aged 25–64 years in an initial target group.
The rate in the elderly notably fell far short of the typical 65% rate for seasonal flu vaccine, but still was substantially higher than the 14% rate in middle-aged adults who did not have risk factors that placed them in the initial target group, Dr. Schuchat said.
The national median rate for children aged 6 months to 17 years reached 37%, which is a “a big jump” above prior flu vaccination efforts, she said. In the 2008–2009 season, for example, immunization with seasonal flu vaccine occurred in about 24% of children aged 6 months or older.
For all Americans aged 6 months or older, the median H1N1 vaccination rate was 24%, the CDC reported in the MMWR. As of the end of February 2010, between 72 million and 81 million Americans had received at least one dose of the H1N1 vaccine, Dr. Schuchat said.