title: Influenzavirus infection is a primary cause of febrile respiratory illness in HIV-infected adults, despite vaccination.
abstract: BACKGROUND
  There are, to our knowledge, no prospective studies of respiratory tract infections in human immunodeficiency virus (HIV)-infected adults in the highly active antiretroviral therapy (HAART) era. We performed a surveillance study of outpatients who presented with fever and respiratory symptoms to examine the role of viral pathogens in these patients.
  
  
  METHODS
  Consecutive patients with a temperature of >38.0 degrees C and respiratory symptoms were recruited from a tertiary care HIV clinic during the period 2003-2006. Nasal pharyngeal samples were tested for influenzavirus A and B, respiratory syncytial virus, and human metapneumovirus using real-time multiplex polymerase chain reaction assays. Paired acute- and convalescent-phase serum samples were tested for respiratory viruses by complement fixation.
  
  
  RESULTS
  Fifty patients (90% of whom were receiving HAART) were included in the study (median CD4(+) T cell count, 325 cells/microL; median HIV RNA level, <50 copies/mL). A causative pathogen was identified in 25 patients (50%). Even though 76% of subjects had received influenza vaccine, viral infections were diagnosed in 21 patients (42%), as follows: influenza A, 10 patients; influenza B, 10; and parainfluenza virus type 3 infection, 1. Patients with and those without viral infection had similar demographic characteristics and HIV statuses. No patients with influenza and 23% of patients with other conditions had radiography-confirmed pneumonia (P=.07). Antibiotic prescriptions were common: 70% of patients received antibiotics. No patients with influenza required hospitalization, compared with 21% of other patients (P=.03).
  
  
  CONCLUSIONS
  Although illness was mild, influenza accounted for a large proportion of unscheduled visits to a health care provider for respiratory illness and was associated with unnecessary antibiotic prescriptions that may contribute to antimicrobial resistance. Vaccination alone was insufficient to prevent infection. Thus, specific identification and management of influenza should be performed in HIV-infected outpatients who present with fever and respiratory symptoms.
authors.affiliation: Department of Medicine, Division of Infectious Diseases, Royal Victoria Hospital, McGill University Health Centre, Montreal, Quebec, Canada. marina.klein@muhc.mcgill.ca
authors.forename: Marina B
authors.initials: MB
authors.lastname: Klein
authors.forename: Ying
authors.initials: Y
authors.lastname: Lu
authors.forename: Lina
authors.initials: L
authors.lastname: DelBalso
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Coté
authors.forename: Guy
authors.initials: G
authors.lastname: Boivin
mesh_terms: D000328:Adult; D017677:Age Distribution; D023241:Antiretroviral Therapy, Highly Active / Q000379:methods; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D005334:Fever / Q000453:epidemiology / Q000503:physiopathology / Q000821:virology; D015658:HIV Infections / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D007252:Influenza Vaccines / Q000008:administration & dosage*; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D009975:Orthomyxoviridae / Q000302:isolation & purification; D011336:Probability; D011379:Prognosis; D011446:Prospective Studies; D012141:Respiratory Tract Infections / Q000453:epidemiology* / Q000503:physiopathology / Q000821:virology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012720:Severity of Illness Index; D017678:Sex Distribution; D018709:Statistics, Nonparametric
chemical_list: D007252:Influenza Vaccines