A case-control study of influenza vaccine effectiveness among Malaysian pilgrims attending the Haj in Saudi Arabia

Objectives: To determine influenza vaccine effectiveness against clinically defined influenza-like illness among Malaysian pilgrims attending the Haj in Saudi Arabia. Methods: During February and March 2000, the authors conducted an unmatched case-control study. Case patients were identified at o...

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Bibliographic Details
Main Authors: Mustafa, Amal Nasir, Abdullah, Nasuruddi, Bradford D, Gessner, Raman, Ismail, Yusoff, Ahmad Faudzi, Ishak, Ilina, Mohd Ismail , Merican
Format: Article
Language:English
Published: Elsevier 2003
Subjects:
Online Access:http://irep.iium.edu.my/30760/
http://irep.iium.edu.my/30760/
http://irep.iium.edu.my/30760/
http://irep.iium.edu.my/30760/1/A_case_control_study_1-s2.0-S1201971203900543-main.pdf
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Summary:Objectives: To determine influenza vaccine effectiveness against clinically defined influenza-like illness among Malaysian pilgrims attending the Haj in Saudi Arabia. Methods: During February and March 2000, the authors conducted an unmatched case-control study. Case patients were identified at one of five hotel clinics, while controls were residents of these hotels who had not attended a clinic. Results: Among 820 case patients–84% of whom had received antibiotics—and 600 controls, the adjusted vaccine effectiveness against clinic visits for influenza-like illness was 77% (95% confidence interval: 69,83), and that against receipt of antibiotics was 66% (95% confidence interval, 54, 75). The vaccine did not prevent clinic visits for non-influenza-like upper respiratory tract illness (adjusted vaccine effectiveness, 20%; 95% confidence interval: −24,49). Conclusions: Influenza vaccine was effective in preventing clinic visits for influenza-like illness and antibiotic use. Pilgrims traveling to the Haj in Saudi Arabia should consider influenza vaccination use.