Background: Hajj is an annual religious ritual that takes place for a specific period in Makkah city. Every year, the Kingdom of Saudi Arabia hosts more than two million pilgrims from more than 160 countries around the world for Hajj. It is crucial to minimize illnesses among pilgrims. This study aimed to assess the impact of preventive measures on acute illnesses among pilgrims. Methods: A retrospective cross-sectional study was conducted during the Hajj season from August to September 2019. A random sample was extracted from electronic evaluation forms filled by professional health care workers at two airports in Saudi Arabia including pilgrims before their departure and after the end of hajj season. Results: The study included 2,479 pilgrims. The most frequently associated comorbidity was Diabetes Mellitus in 49.54%. Upper respiratory tract infection was found in 39.17% and was the most common illness reported. Comorbidities had a crude odds ratio (OR) of 2.67 with a p-value of 0.000 and an adjusted OR of 2.80 with p-value of 0.000. The pre-Hajj examination had an OR of 0.37 with a p-value 0.000 that remained significant even after adjusting age and gender. Hajj health education had a crude OR of 0.17 with a significant p-value of 0.000 and adjusted OR 0.39 with p-value 0.003. Conclusion: Based on the current observation, strict compliance with standard pre-Hajj clinical examination, health education, and the use of umbrella during Hajj seasons is recommended to reduce the impact of acute illness among pilgrims.

Keywords: Hajj; preventive measures; health education; chronic diseases; mass gatherings