Influenza is a disease caused by a virus that is passed from person to person through exposure to fluid droplets that contain the virus. Thus, the majority of transmission is caused by physically being coughed or sneezed upon or coming in contact with a surface shortly after it had been coughed or sneezed upon (Centers for Disease Control and Prevention (CDC), 2008). Symptoms of influenza infection include fever, cough, sore throat, runny or stuffy nose, muscle aches, headaches, and fatigue. The one universal symptom of influenza is the fever (CDC, 2011). The primary approach for combating influenza is prevention, through vaccination.
Recent reports do indicate that there may be a shortage of vaccine in the coming influenza season, with an estimated delay of vaccination seen with up to fifty percent of the at risk population. Thus, if prevention is not successful for this reason or simply a lack of vaccination, there are two prescription anti-viral medications recommended to treat the strains of influenza anticipated to be part of the 2012-13 flu season, zanamivir (Relenza) and oseltamivir (Tamiflu) (CDC, 2013). The following report will discuss issues surrounding the upcoming influenza season, continue with recommendations and conclude with a brief suggested infection control policy for the local community.
Questions from Leadership Regarding Anti-viral Treatment
The anticipated need to possibly rely more heavily on anti-viral treatment this influenza season has raised several questions concerning these treatments and their side effects. A first question is what is and how common are the most prevalent side effects? A related question is whether these are enough of a problem to preclude chemoprophylaxis (preventative administration)? The most common side effect from Tamiflu is nausea and vomiting, which occurred in 6.1% of patients (Genentech, n.d.). This can be reduced if taken with food. The most common side effect with Relenza, which is an inhaled powder, is trouble breathing. This has caused Relenza to not be recommended for patients with underlying airway disease, such as asthma or chronic obstructive pulmonary disease (COPD) (NIH, 2011). However, these problems can be avoided by screening patient populations or are not severe enough to make preventative use these medicines too great of a risk and they are approved by the FDA for certain age ranges in this way (CDC, 2013a).
A second question is what is the impact of anti-viral drug resistance with influenza viruses? Currently, 99% of all circulating strains are sensitive to the anti-viral drugs present in Tamiflu and Relenza. However, this could change and the CDC will be monitoring for this issue. If resistance is developed this would impact the recommendations of use for the drugs (CDC, 2013a).
A third question related to side effects of anti-virals is how common are allergic reactions? Allergic reactions to the drugs are very rare. However, Relenza includes lactose in its formulation, so anyone with an allergy to that should avoid that medicine as swelling of the throat and face have resulted (CDC, 2013a). A fourth and final questions addresses a rare but serious side effect of anti-virals involving transient neuropsychotic events that can include self-injury. What precautions should we take to avoid this? This is a serious side effect that needs to be monitored for. A predisposition of persons of Japanese heritage for this side effect is helpful in focusing monitoring efforts (CDC, 2013a).
Lessons from Past Influenza Seasons
There have been several lessons learned from the more serious influenza seasons, particularly 2009-10 that was characterized by the presence of the H1N1 strain. The first of these lessons is that following hospitalization numbers can be useful in tracking both the time path and severity of a flu season. Numbers are tracked on a weekly basis by the CDC and are available on their website (CDC, 2013c). A high peak early in the season could be either an early peak or a severe season. Hospitalization rates broken down by age can be useful in differentiating between an early peak and a more severe season (Wolf, 2012). If the ages of patients are different than a U-shaped curve from youngest to oldest, this suggests the strains are impacting young people more often than usual, reflective of a severe season rather than just an early peak.
A second less is that vaccination remains the best tool for containing influenza (Wolf, 2012; CDC 2013c). Although treatment is available, the need to both recognize that the illness is influenza and administer the medicine at an early stage for effective treatment makes preventing infection altogether the best course. A final lesson is that stay-at-home and hand washing campaigns are also effective methods of combating spread of influenza infection (Wolf, 2012; CDC 2013c). The importance of community education and outreach cannot be underestimated, particularly when a season is predicted to have vaccine shortages.
Recommendations Regarding Anticipated Vaccine Shortage
The following two recommendations are made considering the possibility of a vaccine shortage. First, vaccines should be preferentially given to the highest at risk persons such as young children, pregnant women, people with chronic health problems and those over 65 (CDC, 2013c). This will focus our best measures where they are most likely to have the greatest impact. Second, measured use of anti-viral drugs for preventative treatment should be initiated if the strains prove to have high impact on low risk and therefore unvaccinated populations. This is because of the relatively low side effects risk and proven ability to reduce transmission (CDC, 2013a).
Community Infection Control Policy
An effective local community infection control policy can be based upon the “Take 3” actions campaign being promoted by the CDC (2013b). The first of the actions recommended is to get vaccinated. With the possible vaccine shortages and recommended targeting of the available vaccine to high risk populations, this could prove more difficult than in prior years. However, it remains that even in years where vaccine is plentiful the recommended levels of vaccination are not met, so continued emphasis on vaccination is still justified.
The second action recommended by the CDC is following standard approaches for avoiding infection (2013b). This is particularly helpful for diseases like influenza where moisture droplets are needed to keep the virus alive outside the body. Thus, just by avoiding sick people and, if becoming sick, staying home makes important inroads in the rate of infection. Using proper hygiene with tissues and coughing are very useful, as is washing hands with soap and water or an alcohol-based hand rub. Disinfecting surfaces can also help with prevention of the spread of influenza.
The final action recommended by the CDC is to take anti-viral drugs if they are prescribed. This of course requires a visit to the doctor at an early stage, when the anti-viral medicines are still helpful. Although the past few influenza seasons have seen an increased awareness of the availability of anti-virals and the timing needed for treatment effect, continued community instruction will help promote the drugs’ effective use. If these three actions are followed by the community, it will have a positive effect on controlling influenza infection in the coming flu season.
References
Centers for Disease Control and Prevention. (2008). Clinical signs and symptoms of influenza. Retrieved from
http://www.cdc.gov/flu/professionals/acip/clinical.htm
Centers for Disease Control and Prevention (2011). Flu symptoms & severity. Retrieved from
http://www.cdc.gov/flu/about/disease/symptoms.htm
Centers for Disease Control and Prevention (2013a). Antiviral agents for influenza.
Retrieved from
http://www.cdc.gov/flu/professionals/antivirals/antiviral-agents-flu.htm
Centers for Disease Control and Prevention (2013b). CDC says “take 3” actions to fight the flu. Retrieved from
http://www.cdc.gov/flu/protect/preventing.htm
Centers for Disease Control and Prevention (2013c). Situation update: Summary of weekly FluView. Retrieved from
http://www.cdc.gov/flu/weekly/summary.htm
Genentech (n.d.). Highlights of Tamiflu prescribing information. Retrieved from
http://www.gene.com/download/pdf/tamiflu_prescribing.pdf
National Institutes of Health (2011). DailyMed. Relenza. Retrieved from
http://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=d7c3bcc3-0c0d-4068-fd80-88cf54a376ef
Wolf, M. (2012 January 11). Flu season could be deadly or dud. Health Policy Solutions. Retrieved from
http://www.healthpolicysolutions.org/2012/01/11/flu-season-could-be-deadly-or-a-dud/
