title: Epidemiology of H1N1 (2009) influenza among healthcare workers in a tertiary care center in Saudi Arabia: a 6-month surveillance study.
abstract: BACKGROUND
  Certain emerging infections, such as severe acute respiratory syndrome and avian influenza, represent a great risk to healthcare workers (HCWs). There are few data about the epidemiology of H1N1 influenza among HCWs.
  
  
  METHODS
  We conducted a prospective surveillance study for all HCWs at King Abdulaziz Medical City (Riyadh, Saudi Arabia) who were confirmed positive for H1N1 influenza by polymerase chain reaction (PCR) from June 1 through November 30, 2009.
  
  
  RESULTS
  During 6 months of surveillance, 526 HCWs were confirmed positive for H1N1 influenza. The distribution of these cases showed 2 clear outbreaks: an initial outbreak (peak at early August) and a shorter second wave (peak at end of October). Among all PCR-confirmed cases, the attack rate was significantly higher in clinical HCWs than in nonclinical HCWs (6.0% vs 4.3%; P < .001) and in HCWs in emergency departments than in HCWs in other hospital locations (17.4% vs 5.0%, P < .001). The percentage of HCWs who received regular influenza vaccination was greater for clinical HCWs than for nonclinical HCWs (46.2% vs 24.6%; P < .001). The majority of HCWs with confirmed H1N1 influenza were young (mean age + or - standard deviation, 34.5 + or - 9.5 years), not Saudi (58.4%), female (55.1%), and nurses (36.1%). Approximately 4% of women who were less than 50 years old were pregnant. Reported exposures included contact with a case (41.0%), contact with a sick household member (23.8%), and recent travel history (13.3%). Respiratory symptoms (98.0%), including cough (90.1%), were the most frequently reported symptoms, followed by muscle aches (66.2%), fever (62.5%), headache (57.9%), diarrhea (16.5%), and vomiting (9.8%). None of these HCWs died, and all recovered fully without hospital admission.
  
  
  CONCLUSIONS
  The results confirm the vulnerability of HCWs, whether clinical or nonclinical, to emerging H1N1 influenza.
authors.affiliation: King Abdulaziz Medical City, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia. balkhyh@hotmail.com
authors.forename: Hanan H
authors.initials: HH
authors.lastname: Balkhy
authors.forename: Aiman
authors.initials: A
authors.lastname: El-Saed
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Sallah
mesh_terms: D000328:Adult; D004196:Disease Outbreaks; D005260:Female; D006282:Health Personnel; D006761:Hospitals / Q000706:statistics & numerical data*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000302:isolation & purification*; D007251:Influenza, Human / Q000175:diagnosis / Q000453:epidemiology* / Q000821:virology; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods; D011159:Population Surveillance / Q000379:methods*; D011446:Prospective Studies; D012529:Saudi Arabia / Q000453:epidemiology; D055815:Young Adult