Detection of respiratory viruses among pilgrims in Saudi Arabia during the time of a declared influenza A(H1N1) pandemic.

BACKGROUND

The objectives of this study were to determine whether pilgrim attendance at the Hajj was associated with an increased risk of acquiring influenza, and other respiratory viruses, and to evaluate the compliance of pilgrims with influenza vaccination and other recommended preventive measures.

METHODS

A cross-sectional survey was conducted among pilgrims as they arrived at the King Abdulaziz International Airport in Jeddah for the 2009 Hajj and as they departed from the same airport during the week after the Hajj. Nasopharyngeal and throat swabs were tested for 18 respiratory virus types and subtypes using the xTAG Respiratory Viral Panel FAST assay.

RESULTS

A total of 519 arriving pilgrims and 2,699 departing pilgrims were examined. Their mean age was 49 years and 58% were male. In all, 30% of pilgrims stated that they had received pandemic influenza A(H1N1) vaccine before leaving for the Hajj and 35% of arriving pilgrims reported wearing a face mask. Only 50% of arriving pilgrims were aware of preventive measures such as hand hygiene and wearing a mask. The prevalence of any respiratory-virus infection was 14.5% (12.5% among arriving pilgrims and 14.8% among departing pilgrims). The main viruses detected (both groups combined) were rhinovirus-enterovirus (N = 414, 12.9%), coronaviruses (N = 27, 0.8%), respiratory syncytial virus (N = 8, 0.2%), and influenza A virus (N = 8, 0.2%) including pandemic influenza A(H1N1) (N = 3, 0.1%). The prevalence of pandemic influenza A(H1N1) was 0.2% (N = 1) among arriving pilgrims and 0.1% (N = 2) among departing pilgrims. The prevalence of any respiratory virus infection was lower among those who said they received H1N1 vaccine compared to those who said they did not receive it (11.8% vs 15.6%, respectively, p = 0.009).

CONCLUSION

We found very low pandemic influenza A(H1N1) prevalence among arriving pilgrims and no evidence that amplification of transmission had occurred among departing pilgrims.