We presumed other causes or etiological agents responsible for respiratory symptoms in this cohort. The previous study had shown find more that influenza A virus was only detected in 0.6%,31 8.1%,32 8.6%,17 and 10.2%,29 respectively, of the hajj pilgrims. Other earlier studies also showed that the crude ILI attack rate among vaccinated persons was significantly lower than control group.21,33 But later, another study showed that influenza vaccine appeared to provide some protection against influenza in immunosuppressive conditions and those hajj pilgrims over the

age of 65 but not in the others.34 In the previous study by Meysamie et al. (2006), the rate of respiratory diseases significantly increased from 35% in year 2004 to 70% in 2005 LBH589 molecular weight with the increment of influenza vaccination coverage.24 In the era of H1N1 pandemic influenza, the ILI cases increased five times more than baseline rate and the pandemic influenza strain took over the seasonal vaccine strain.35 There was no epidemiological evidence of significant protection by seasonal vaccine against pandemic influenza virus infection.36 Although some cross protection of H3N2 was documented

when the subjects are injected by H2N2 vaccine, the protection of H1N1 pandemic influenza 2009 is not expected after vaccination with H1N1 2008 strain because of major different in antigenic site.37 H1N1 pandemic strain vaccination is expected to be the best solution for ILI prevention at the moment. While waiting for the vaccine to appear in the market, infective control measures were implemented, including to hajj pilgrims. Restricting high-risk Muslims from performing hajj this year was one of the options.38 Regular reminders on personal hygiene, avoiding mass crowds as much as possible, reducing unnecessary exertions and taking a lot of water are very important to minimize the problem

with respiratory symptoms. In conclusion, respiratory symptoms were very common among Malaysian hajj pilgrims. The current protective measures are inadequate to give protection. Future research should be aimed at finding other possible interventions which could reduce respiratory infections. As the number of hajj pilgrims increases BCKDHA each year, these measures ought to be instituted soon. Future studies should also aim at standardization of the terms used and be done in collaboration with researchers from the host nation. This study was funded by Ministry of Higher Education, Malaysia through Universiti Sains Malaysia Hajj Research Cluster. We also would like to acknowledge the Custodian of Two Holyland Hajj Research Center, University of Umm al Qura, Makkah for support with the accommodation and transportation during research in Makkah; Tabung Haji Malaysia for continuous support; and Ms Rohana Che Yusof and Mr Mohd Bazlan Hafidz Mukrim for helping in the data key-in.