CDC: Flu Vaccine for All, Again

Although the influenza strains included in the upcoming season's trivalent vaccine are unchanged from last season, the CDC is still recommending that everyone older than 6 months get vaccinated this year.

This season's vaccines, which have already begun to ship, protect against the pandemic H1N1 virus, as well as an H3N2 and a B strain, the same as last season, according to new recommendations from the Advisory Committee on Immunization Practices (ACIP) published in Morbidity and Mortality Weekly Report.

Even so, because studies have shown that protection can wane in the year after receiving the vaccine, everybody who is eligible should be vaccinated again this season, said Carolyn Bridges, MD, of the CDC's National Center for Immunization and Respiratory Disease, on a conference call with reporters.

One group of individuals who might not need as much vaccine as in years past are children younger than 9. Normally, these children would need two doses to provide sufficient protection against the flu. But because the strains are the same as last season, any children who received at least one dose of vaccine last season only need to get one for the upcoming season, according to the recommendations.

Although the guidance is largely similar to that from previous seasons, additional updates include the availability of the intradermal formulation of Fluzone -- which was approved by the FDA in May -- and new recommendations regarding vaccination in individuals with egg allergy -- which were discussed at one of ACIP's meetings in June.

Included in the recommendations for vaccination in the presence of egg allergy:

• Those with a history of hives only after exposure to egg can receive influenza vaccine, but should receive the trivalent inactivated vaccine (TIV) rather than the live attenuated influenza vaccine (LAIV), should be vaccinated by a healthcare provider who is familiar with potential manifestations of egg allergy, and should be observed for at least 30 minutes following administration.
• People who have had more severe allergic reactions to egg should be referred to a physician with expertise in the management of allergies for further risk assessment.
• The vaccine should be administered in settings equipped for the rapid recognition and treatment of anaphylaxis.

The authors noted that a previous severe allergic reaction to influenza vaccine, regardless of the component causing the reaction, is a contraindication to getting the vaccine.

Although the CDC recommends that everyone get an influenza vaccine every year -- barring a contraindication -- certain groups have been identified as high priorities for vaccination.

Two such groups -- healthcare personnel and pregnant women -- were the subject of MMWR reports this week.

Both included comparisons based on Internet surveys of vaccination rates in the 2010-2011 season with those in the 2009-2010 season -- which included the H1N1 pandemic.

For healthcare personnel, in whom vaccination protects both the individual workers and any patients they encounter, receipt of the trivalent seasonal vaccine changed little, from 61.9% in 2009-2010 to 63.5% in 2010-2011. The vaccination rates in 2009-2010 were higher than in the previous decade, attributed to the H1N1 pandemic.

Nearly all of those who worked at a facility that required vaccination (98.1%) were vaccinated, compared with just 58.3% of those without such a requirement.

Among healthcare personnel who worked at a facility that did not have mandatory vaccination but offered vaccine on site, factors associated with a greater likelihood of receiving flu vaccine were a personal reminder from the employer to get immunized (OR 1.6, 95% CI 1.1 to 2.3) and the availability of free vaccine for more than one day (OR 2.8, 95% CI 1.7 to 4.5).

The coverage rate for pregnant women also showed little change from 2009-2010 to the most recent season.

Historically, the vaccination rate has hovered around 15%, although that spiked to about 50% during the H1N1 pandemic.

Nearly half of respondents (49%) reported receiving flu vaccine during the peak of the 2010-2011 season, still well below the Healthy People 2020 goal of 80%.

The advice of a healthcare provider appeared to be influential in a pregnant woman's decision to get vaccinated, as the coverage rate was dramatically higher among women who were offered the vaccine by their doctor (71% versus 14%).

"The study underscores the fact that continuing efforts are needed to encourage providers to strongly recommend and to offer vaccination to their pregnant patients," Bridges said.