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Influenza and Adults A Patient-Specific Approach to Universal Immunization © Digital Vision/Getty Images
Dear Colleague: It’s an extraordinary concept, really. Despite the medical breakthroughs of the last century—advances in antimicrobial therapy, advances in immunization—influenza and pneumonia still rank among the top killers of adults in the United States. A seasonal influenza outbreak can put hundreds of thousands of people in the hospital and result in tens of thousands of deaths. Those numbers are not acceptable. The licensure of new influenza vaccines in recent years, with others in the pipeline, gives health professionals more tools to customize their approach to flu prevention in the context of a universal immunization recommendation. Vaccines geared toward select groups of adults (eg, those over 65 years of age), or administered other than intramuscularly, complement traditional influenza vaccines. Age, health status, and patient preferences should all be factored into the mix in vaccinating patients. But getting vaccines from shelf to patient remains a challenge, one that you can help meet by implementing immunization strategies such as those presented in this newsletter. Beyond these practical strategies, it’s important that we impress upon our patients our determination to get everyone immunized. It should be crystal clear to your patients that you and your staff are passionate about protecting them against the flu.
Sincerely,
William Schaffner, MD FACULTY REVIEWER William Schaffner, MD Professor and Chair Department of Preventive Medicine, Vanderbilt University School of Medicine Nashville, Tennessee
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he Centers for Disease Control and Prevention (CDC) has endorsed universal influenza vaccination since 2010, when it expanded its recommendations for annual immunization to include everyone 6 months of age and older.1 Evidence supports the safety and effectiveness of influenza vaccination across all demographic groups, including healthy, nonpregnant adults 18-49 years of age, most of whom were previously excluded from recommendations for routine immunization.1 One analysis of the annual toll of seasonal influenza in the United States estimated that the disease was responsible for 5 million illnesses, 2.4 million outpatient visits, 32 000 hospitalizations, and 680 deaths among otherwise healthy adults 18-49 years of age.1 The burden of influenza, however, continues to fall disproportionately on older adults. Adults ≥65 years of age, along with children <2 years of age and people of any age who have an underlying medical condition that puts them at increased risk of influenza-related complications, have the highest rates of serious illness and death from the disease.1 During 1976-2007, the estimated annual number of influenza-related deaths from respiratory and circulatory causes ranged from 2344 to 43 727 among adults ≥65 years of age.2 Approximately 90% of all influenza-associated deaths occur among adults in this age group.2 This group is also more likely to have a reduced response to traditional influenza vaccines, due to immunosenescence—the gradual decline in immune function that accompanies aging. Pregnant women are another vulnerable population. In their second or third trimester, they are 4 times more likely than their nonpregnant counterparts to be hospitalized for flu-related complications.3 During the pandemic of 2009-2010, 75 of 347 (22%) severely ill pregnant women died from H1N1 influenza; 272 (78%) were admitted
to an intensive care unit and survived.4 Some studies have linked maternal influenza to adverse birth outcomes, including fetal distress, preterm labor, and low birth weight.1,4 Maternal influenza vaccination has been associated with improved fetal and neonatal outcomes.5 Although seasonal influenza vaccination rates for pregnant women have risen substantially since the years prior to the 2009 H1N1 pandemic, it’s estimated that only 47% of pregnant women were immunized for the 2011-2012 flu season.6 Across all ages and risk groups, coverage rates fall well short of Healthy People 2020 goals for seasonal influenza immunization (Figure 1).7,8 Overall, the estimated immunization rate for adults ≥18 years of age for the 2011-2012 flu season was 39%.8 Rates among adults at high risk of influenza-related complications remain disappointingly low—37% in the 18- to 49-year age group for 2011-2012.8 Rates for adults ≥65 years of age have stagnated in the range of 65%-70% in recent years.1,8 Racial disparities in adult immunization have also endured. It’s estimated that 33% of non-Hispanic black adults and 29% of Hispanic adults were immunized against influenza during the 2011-2012 season, compared to 42% of non-Hispanic white adults.8 Among health care personnel, 1 in 3 did not receive the vaccine during the 2011-2012 flu season.9 Why aren’t more adults getting vaccinated? Adult immunization rates are suboptimal for all recommended vaccines. Barriers to immunization of adults include lack of patient knowledge about the risks of vaccine-preventable disease and concerns about vaccine safety and effectiveness.10,11 Barriers cited by health care professionals include the infrequency of adult well-visits, lack of systems for identifying