Highlights of the Advisory Committee on Immunization Practices' Prevention and Control of Influenza for 2007-2008

Highlights of the Advisory Committee on Immunization Practices' Prevention and Control of Influenza for 2007-2008

Seasonal epidemics of influenza and influenza-like illnesses continue to have a major impact upon the population of the United States, resulting in approximately 36,000 deaths and over 200,000 hospitalizations each year during recent decades.^1,2 The Advisory Committee on Immunization Practices (ACIP)³ published its recommendations for the upcoming 2007-2008 influenza season in the July 13th issue of the Centers for Disease Control's Morbidity and Mortality Weekly Report (MMWR). This yearly publication provides a review of the influenza disease patterns for the prior year, recommendations on immunization practices and treatment for the upcoming influenza season, and new and updated treatment recommendations.

One of the most important updates is on the composition of the trivalent vaccines for 2007-2008. A new H1N1 strain of influenza A, the A/Solomon Islands/3/2006 strain, is included in both the injected trivalent inactivated influenza vaccine, and the inhaled live attenuated influenza vaccine (LAIV), along with A/Wisconsin/67/2005-like (H3N2), and B/Malaysia/2506/2004-like viruses. The inclusion of this new strain is the first change in the H1N1 vaccine strain since the 2000-2001 influenza season,⁴ and is in response to an antigenic drift of the influenza virus. As many people in the United States will have limited cross-immunity to this particular H1N1 strain, immunization is necessary to prevent disease. The report reinforces that providers should offer influenza vaccination throughout the season, which extends into March of each year. Although influenza immunity requires approximately 2 weeks to take effect, it is never too late to receive the vaccine during the influenza season.

The immunization of children is further emphasized and detailed in this report. The report reiterates the new formulation of LAIV introduced in January of 2007, with single-use sprayers dosing 0.1 mL per nostril for children >5 years of age and adults. The need for 2 doses of either trivalent inactivated influenza vaccine or LAIV among children aged 6 months to 8 years is re-emphasized. Also, children 6 months to 8 years who received only 1 dose in their first year of vaccination should receive 2 doses the following year. These recommendations attempt to prevent a repeat of the morbidity and mortality seen in children during the 2003-2004 influenza season.⁵ During that season, there were 153 laboratory-confirmed deaths, 100 of which were among children without an underlying medical condition. The latter data suggested the likelihood that these deaths were potentially preventable by vaccination.

The report also lists the estimated immunization rates of adults, and reinforces immunization of particular risk groups. For example, influenza vaccination rates among pregnant women were 15% for 2005, despite the endorsement of immunization of pregnant women by the American College of Obstetricians and Gynecologists, and the American College of Family Physicians, respectively.⁶ At the other end of the age spectrum, immunization of adults aged 50 to 64 were estimated to be only 32% and 66%, respectively, of those >65 years of age in the first quarter of 2006.⁷ However, these figures remain well below the goal of 90% vaccine coverage within this age group by 2010.⁸ A final group which deserves mention are healthcare professionals, whose immunization rates were estimated to be only 33.5% in 2005. With a number of published studies noting the value of immunizing healthcare workers, it is difficult to reconcile that only 1 in 3 healthcare professionals chose to be vaccinated against influenza. A new recommendation from the ACIP is that healthcare administrators should consider the level of influenza vaccination coverage as a measure of patient safety quality. This recommendation should be applauded and implemented.

In summary, strategies to improve the vaccination rates of the US population are detailed and well referenced among the ACIP recommendations. Encouraging the use of alternative sites, such as grocery stores, pharmacies, and the workplace, to improve vaccination rates is welcomed. Perhaps it is time to consider other creative strategies for improving influenza vaccination coverage as well.