Objectives: To estimate the prevalence of acute respiratory tract infections (ARI) among 250 personnel serving in a Hajj medical mission, Al-Hada and Taif Armed Forces Hospitals, during the 2005 season and to determine the effectiveness of protective measures, including influenza vaccination, for these infections. Methods: This was a nested case-control study. A questionnaire was distributed to the study cohort two weeks after the Hajj period and was self-administered by all recruited subjects. In addition, the medical records of study subjects were reviewed at Al-Hada Hospital for the same period in order to document ARI. Results: The attack rate for ARI among study subjects during Hajj season or within two weeks of returning was 25.6% (64/250). Logistic regression analysis of factors related to acquiring ARI revealed that contact with pilgrims imposed an extremely high risk of infection (adjusted OR 13.2, 95% CI 1.5-117.6). Moreover, non-use of alcohol-based hand disinfection carried a more than 8-fold risk of acquiring ARI compared to those who always used alcohol. for hand disinfection (adjusted OR 8.4, 95% CI 2.2-32.2). Smoking was also a predictor of ARI in our cohort and influenza vaccination was associated with a 30% reduction in ARI compared to unvaccinated subjects, although this finding was not statistically significant. Unexpectedly, the logistic regression model showed that Saudi nationals were three times more likely to acquire ARI than non-Saudis (adjusted OR 3.1, 95% CI 1.2-8.4). Conclusions: The common practice among pilgrims and medical personnel of using surgical facemasks to protect themselves against ARI should be discontinued and regular use of alcohol-based hand scrubs should be more vigorously encouraged. Further research is needed to evaluate the protective value of N95 facemasks against ARI during the Hajj period. (C) 2006 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.
