Flu Vaccine Recommended for All Adults

In late February 2009, the Advisory Committee for Immunization Policies (ACIP) of the Centers for Disease Control and Prevention (CDC) expanded its guidelines on who should take the seasonal influenza vaccination in the 2010-2011 flu season. ACIP advises, and CDC will likely recommend, that all adults should receive the seasonal flu vaccine. In previous years, healthy adults ages 19-49 with no underlying risk factors were not recommended to receive the vaccine.

Now all people 6 months and older are recommended to be vaccinated for seasonal influenza.

Read ACIP’s provisional recommendation here.

What will this mean?

First, the recommendation will greatly simplify the guidelines. In the 2009-2010, a complicated set of conditions recommended seasonal flu vaccination to adults in five main categories, including three subcategories. (See the complete list at CDC’s Key Facts About Seasonal Flu Vaccine, at least until the new guidelines are adopted.) Effectively, the new recommendation will state that all individuals ages 6 months and up, who don’t have contraindications, should receive the seasonal flu vaccine.

Clearly, past recommendations for flu vaccination in adults did not result in full coverage: in the 2006-2007 influenza season, only about 37% of high-risk adults ages 18-49 took the seasonal flu shot (National Immunization Survey 2007, CDC). It’s possible that the simplified recommendation may reduce confusion among the general public, leading to increased uptake.

Second, according to Thomas Fekete, MD, Section Chief of Infectious Diseases at Temple University School of Medicine, ACIP’s recommendation may lead the general public to think about influenza differently. He suggests that we may come to regard influenza as a community issue as well as an individual one: “We’ve been more accustomed to thinking of community vaccination benefits when it comes to childhood illnesses like polio and pertussis, but universal flu vaccination for all adults may lead us to engage more fully in questions about community health as they relate to adult illnesses.”

The new recommendations may lead to a secondary benefit to people who don’t (or can’t) get vaccinated, or who don’t have a robust reaction to the vaccine. In fact, a recently published large-scale study showed an overall reduction in seasonal flu incidence when all children in a community were vaccinated (Loeb MB, et al. Effect of influenza vaccination of children on infection rates in Hutterite communities: A randomized trial. JAMA, 2010; 303 (10): 943-950). We don’t know whether universal flu vaccination of adults will have the same effect of interrupting flu transmission, but presumably researchers will look at this question.

Future studies will, no doubt, evaluate the costs and benefits of this new influenza vaccination strategy. For now, the guidelines will certainly be much simpler to explain and remember.