02). In the HIV-positive group, prior or current AIDS-defining events were reported for 30% of patients, 9% and 30% had CD4 counts of <200 and 200–500 cells/μL, respectively,

and 95% had HIV-1 RNA <50 copies/mL. Pneumonia (9%vs. 25%, respectively, in the HIV-positive and HIV-negative groups; P=0.01) and respiratory failure (9%vs. 21%, respectively; P=0.04) were less common in the HIV-positive group. Oseltamivir RG7204 in vitro (95%vs. 71% in the HIV-positive and HIV-negative groups, respectively; P=0.003) was administered more often in HIV-positive patients. Three patients (all HIV-negative) died. In the HIV-positive group, CD4 cell count and plasma HIV-1 RNA did Abiraterone not differ before and 4–6 weeks after influenza A H1N1 diagnosis (P>0.05). HIV infection did not increase the severity of influenza A H1N1 infection, and influenza A H1N1 infection did not have a major effect on HIV infection.

Influenza is a common cause of acute respiratory illness in HIV-infected adults [1,2]. Before the widespread use of effective combination therapy, small case series and anecdotal reports suggested that low CD4 cell counts or concomitant respiratory or cardiovascular comorbidities were associated with a higher risk for complications [3–8]. It is unclear to what extent effective antiretroviral therapy may have affected the risk for severe or complicated influenza, but HIV-infected patients are still considered to be Carnitine palmitoyltransferase II at a higher risk [9] and for that reason they are preferentially targeted for influenza vaccination [10–12]. Human infections with a novel A H1N1 influenza virus were first identified in April 2009 [13,14] and they were increasingly reported throughout the world in the following weeks [15]. The rapid spread of the infection and the extensive reporting of associated deaths occupied the attention of the media and contributed to increased awareness

in the general population [16,17]. Data from the beginning of the epidemics suggested that many influenza A H1N1 infections were not necessarily severe [18] and that HIV-infected patients were not overrepresented among those hospitalized or severely ill [14,19–21]. Nevertheless, health authorities considered that HIV-infected patients were at a higher risk for influenza A H1N1 complications, as they were for seasonal influenza, and this assumption remains unchanged [22–24]. With open access to combination antiretroviral therapy, many HIV-infected adults show sustained suppression of HIV replication in plasma, resulting in immunological and clinical benefits [25]. In Spain, health care for chronic conditions such as HIV infection and also for acute conditions and emergencies is provided free of charge by the public health care system [26].