title: Vaccination in Hajj: An Overview of the Recent Findings.
abstract: BACKGROUND
  About two million people annually travel to Kingdom of Saudi Arabia to perform Hajj. The pilgrims may be at risk of exposure to communicable diseases in this mass gathering and their vaccination against contagious diseases can prevent many morbidities and mortalities. The aim of our study was to review the papers which evaluated effectiveness and compliance of the vaccines applied in Hajj.
  
  
  METHODS
  We used PubMed and Scopus to search international medical databases. The key words were as follows: Hajj, Haj, vaccine, vaccination, and immunization. The time interval of the search was from the beginning of 2010 to May 23, 2016. One hundred and thirty papers were extracted, and their contents were subsequently reviewed after title and abstract screenings. The original articles were included in the study and non-English articles were excluded from the study.
  
  
  RESULTS
  Considering the extracted papers, almost all pilgrims were vaccinated against meningococcal diseases. Using of influenza and pneumococcal vaccine rates were different among the pilgrims. The other vaccines have been taking according to specific conditions.
  
  
  CONCLUSIONS
  The findings regarding influenza vaccine effectiveness are contradictory. A few studies confirmed the flu vaccine effectiveness while some others rejected its usefulness. Meningococcal immunization is an effective preventive tool with high compliance for Hajj pilgrims. Further investigations are recommended for the other vaccines.
authors.affiliation: Department of Community Medicine, Research Center for Rational Use of Drugs, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Seyed Mansour
authors.initials: SM
authors.lastname: Razavi
authors.affiliation: Faculty of Medicine, Islamic Azad University, Tehran Medical Branch, Tehran, Iran.
authors.forename: Mina
authors.initials: M
authors.lastname: Saeednejad
authors.affiliation: Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Payman
authors.initials: P
authors.lastname: Salamati
keywords: Communicable diseases; preventive medicine; travel medicine; vaccination