280 updated guidelines for the treatment of patients with con- firmed or suspected influenza virus infections caused by either pandemic H1N1 or seasonal strains [41 , 70 ]. According to these recommendations, those individuals with severe disease (requiring hospitalization or with evi- dence of lower respiratory tract infection) or those at high risk for complications (Table 1) should receive antiviral therapy even after 48 h of symptom onset. Adults with mild illness without high risk conditions who are younger than 65 years of age do not require treatment. If such individuals present within the first 48 h of illness, antiviral treatment can be considered in order to reduce the duration of illness. In all cases, decisions to administer antiviral medications for influenza treatment should be based on clinical and epide- miologic grounds, and never be delayed because of confir- matory laboratory tests [41 ]. The usual dosing of oseltamivir for the treatment of influenza is 75 mg orally twice daily and of zanamivir is 10 mg (2 inhalations) twice daily. The recommended duration for antiviral treatment is 5 days, although longer treatment courses for patients who fail to improve after 5 days of treatment can be considered [70 ]. Also, doubling the dose of oseltamivir to 150 mg orally twice daily has been suggested to be beneficial for some severely ill patients with H5N1 avian influenza [24, 67]. The FDA licensed oseltamivir for use in children 1 year of age and older in a liquid formulation at a dosage of 2 mg/kg/dose twice daily for 5 days. Zanamivir is not approved for use in children under 5. Oseltamivir and zanamivir are Pregnancy Category C drugs, but since influenza causes more severe disease and an increased rate of mortality among pregnant women, they should receive antiviral therapy with oseltamivir when indi- cated, since the potential benefit outweighs the theoretical risk to the fetus (Table 1). Resistance Although oseltamivir-resistant seasonal H1N1 influenza A viruses have been identified since 2007 (the H274Y mutation) [71], in 2009 the CDC reported that most circulating strains of the novel H1N1 influenza A virus were sensitive to the NI, oseltamivir and zanamivir, but that nearly all strains were resistant to the amantadines [41 , 72]. Consequently, the ACIP has advised against the use of M2 inhibitors for treat- ment of influenza, except in selected circumstances [41 ]. Additional Management Strategies It is recommended that patients with pandemic H1N1 influenza A who develop pneumonia be treated empirically for CAP according to published evidence-based guidelines, given the risk of secondary bacterial pneumonia [73]. In the presence of Curr Infect Dis Rep (2012) 14:275–283 profound hypoxemia that has been refractory to routine me- chanical ventilation, salvage therapies include neuromuscular blockade, inhaled nitric oxide, high-frequency oscillatory ven- tilation, extracorporeal membrane oxygenation (ECMO), and prone positioning ventilation [74 , 75]. Corticosteroids should not be used routinely, but may be considered for septic shock with suspected adrenal insufficiency requiring vasopressors [76]. Therapy for influenza-associated ARDS should be based upon published evidence-based guidelines for sepsis-associated ARDS, specifically including lung protective mechanical venti- lation strategies [76]. Prevention The CDC recommends routine annual influenza vaccination for all persons 6 months of age and older. When vaccine supply is limited, vaccination efforts should focus on those groups with health conditions associated with increased risk of influenza complications [40 ]. Antiviral drugs should not be used as a substitute for influenza vaccination. Their adjunctive use is appropriate in certain targeted populations at high risk for complications of influenza who are close contacts with suspected or confirmed cases [Table 1]. Post- exposure prophylaxis should only be used when antivirals can be started within 48 h of the most recent exposure. Recommended duration is 7 days after exposure, and the CDC recommends a minimum of 2 weeks for control of influenza outbreaks in long–term care facilities (i.e., nursing homes with elderly) and hospitals [70 ]. The choice to offer post-exposure prophylaxis to otherwise healthy unvaccinated adults should be weighed against the risk of promoting anti- viral drug resistance [41 , 1 ]. Conclusions A potentially fatal complication of influenza infection is the involvement of the lower respiratory tract caused directly by the influenza virus, and the development of secondary bac- terial pneumonia. In these cases, and in patients who are at an increased risk for influenza infection complications, con- firmation of etiology by laboratory testing is required in order to guide the initiation and duration of antiviral treat- ment, and for the implementation of infection control meas- ures and surveillance. Recently, the emergence of novel influenza A strains that carry the risk for more severe disease regardless of age or previous health status, has prompted the development of quick and reliable laboratory tests in an effort to optimize their management and reduce morbidity and mortality. Pneumonia related to the 2009 influenza A pandemic was found in many cases to be rapidly progressive, leading to respiratory failure which in