Seasonal Influenza: Burden of Illness
According to the US Centers for Disease Control and Prevention, influenza and pneumonia combined were the eighth leading cause of death in the United States. Furthermore, in a 1993 article by Sullivan and colleagues, it was estimated that over 4.1 million people had excess respiratory illnesses due to influenza and that this translated to 16.6-17.9 million restricted activity work days. In a study by Molinari and colleagues, they estimated that in 2003, the cost of caring for influenza in the United States alone would be $10.4 billion with another $16.3 billion in lost earnings and productivity -- with a total economic cost of $87 billion.Seasonal Influenza: Clinical Presentation
Typically patients become infected with influenza by inhalation of respiratory droplets from another infected individual. There is a 1- to 4-day incubation period, and once sick, the patient can be infectious up to 10 days after the onset of symptoms. Typical symptoms include significant malaise, fever, body aches, headache, sore throat, and cough. Unlike common cold symptoms, rhinorrhea and sinus congestion are not as prominent symptoms. Clinical symptoms alone cannot either rule in or rule out the presence of influenza, and rapid testing is now available for both influenza A and B. Secondary bacterial infections are possible, including staphylococcal pneumonia, usually heralded by a rapid worsening of the pulmonary picture and fevers in a patient with previously diagnosed influenza. The influenza virus may also cause a primary viral pneumonia. Most patients recover from influenza with little or no residual problems, although the malaise may last for 2-4 weeks in some cases.Seasonal Influenza: Vaccine and Treatment Rates
Although there are studies that show ranges of efficacy that can be up to 70% to 90% depending on the year for the inactivated influenza vaccine, the vaccination rate in the general population is low (only 48% in 2004). Despite medication being available for those who are diagnosed with the flu, it has been estimated that only 15% of primary care physicians prescribe this medication for those with the flu, and more importantly, 24% who met the criteria did not receive the medication.
Adolescents and college-age students represent groups that are not at high risk for serious disease or mortality, but because of their living and going to school in such close quarters, they can easily spread the infection. Although there are segments of this population that are at higher risk for severe infections, such as those with asthma, HIV, and those who are pregnant, the vast majority are healthy adults for whom there are little trial data to show clinical or economic benefit for mass influenza vaccination. Thus, with its low mortality in this younger population, making a case for universal vaccination of the adolescent and college-age population requires one to look beyond influenza's mortality potential.
There are a few studies, however, that have looked at the impact of vaccination of healthy adults. In one of the only placebo-controlled, randomized trials of 2375 healthy adults, vaccination when well matched (efficacy over 80%) provided protection against influenza-like illness, excess physician visits, and lost workdays by 34%, 42%, and 32%, respectively. This came at an overall cost of $11 per person vaccinated for the healthy adult. The Advisory Committee on Immunization Practices has recently put out its 2007 update of its 2006 recommendations and stated that all healthy people, including school-aged children, who want to reduce their risk of becoming ill with influenza should be vaccinated.
College-age students do not get vaccinated as often as those who are older. Some studies have shown that vaccination is linked to individual health beliefs on susceptibility to influenza and a higher degree of fear about side effects, but also may be related to costs.[9,10] In her August 2007 article, Middleman proposed more use of mandatory vaccinations in adolescents to improve vaccination rates for other vaccines. She noted, however, the potential backlash for making certain vaccinations mandatory. This may be especially true in cases in which the benefit for certain populations in terms of economic outcomes has not been conclusively shown. Developing new models to get messages on susceptibility, safety, and costs to students on influenza vaccination could be an important method to increase the number of students choosing to become vaccinated.
Medscape Infectious Diseases © 2008 Medscape
Cite this: Influenza Vaccination: Challenges for Adolescent and College Healthcare - Medscape - Jan 15, 2008.