The CDC recently announced that the influenza vaccine has been 48% effective this year in preventing influenza illness. Presumably, it has been even less effective in subgroups like the elderly, the immunosuppressed, and those with chronic heart, kidney, or liver disease. The CDC recommends antiviral treatment for documented, or even suspected, influenza illness in these high-risk groups.
The list of high-risk groups the CDC has targeted for antiviral treatment of influenza is quite extensive. They include children <2 years old, persons <19 years old receiving long-term aspirin therapy, adults ≥65 years old, morbidly obese persons (BMI ≥40), women who are pregnant or ≤2 weeks postpartum, persons of American Indian/Alaska Native heritage, residents of nursing homes or other chronic care facilities, and persons who are immunosuppressed or have certain chronic medical conditions (including pulmonary, cardiovascular, renal, hepatic, hematological, metabolic, neurologic, or neurodevelopmental disorders). Antiviral treatment is recommended for all patients with suspected or confirmed influenza who have severe, complicated, or progressive illness, develop symptoms of lower respiratory tract infection, or require hospitalization. Antiviral treatment can be considered even for previously healthy persons with uncomplicated influenza if it can be started within 48 hours of illness onset.
Three drugs are recommended this year for treatment of influenza. All three are neuraminidase inhibitors. Oseltamivir (Tamiflu, and generics) is taken orally. Zanamivir (Relenza) is inhaled. Peramivir (Rapivab) is given intravenously. All three have been shown, if started within 48 hours of the onset of symptoms, to shorten the duration of illness by about one day. None has been shown conclusively to reduce the incidence of complications of influenza, but a strong consensus of infectious disease specialists has interpreted the available data as showing that early antiviral treatment of high-risk patients reduces the incidence of pneumonia, respiratory failure, and death. Influenza kills about 50,000 patients annually in the US. Neuraminidase inhibitors are generally well tolerated, and there is no acceptable alternative treatment.
Unfortunately, neuraminidase inhibitors are expensive. Oseltamivir is now available generically, but even the generic costs more than $100. Patients without insurance, those with high deductibles, high copays, donut holes, etc. may have to pay that much for the requisite 5-day course of the drug.