Hajj and the risk of influenza

Abstract

The threat can no longer be ignored

At the end of next month Saudi Arabia will again host the Hajj—the largest annual gathering in the world—which attracts more than two million pilgrims from almost every country on earth.^{1 2} For the individual pilgrim this is a deeply spiritual journey that represents the culmination of months if not years of preparation. From a public health perspective, however, such a gathering makes the possible rampant spread of the influenza virus and a global pandemic—which many experts believe is overdue—a potentially devastating prospect that has been inadequately prepared for.³

Recent work highlighting the high rates of infection and carriage of influenza virus in pilgrims returning from Mecca has emphasised the need for internationally agreed strategies to minimise the risk of a pandemic.^{4 5 6} Such a strategy should centre on ways to prevent transmission, but must also include facilities for prompt diagnosis and treatment of infected individuals. No such comprehensive strategy currently exists.

The Hajj and its associated rites are a once in a lifetime obligation for people who have the means to undertake the journey. The Hajj attracts ever increasing numbers of men, women, and children from a diverse array of ethnic, linguistic, and social backgrounds.^{1 2} Because the sacred rites are undertaken at the same time, overcrowding is considerable throughout the five day Hajj period. Accommodation is, of necessity, in tents in the desert plains of Mina and Arafat, and it is not unusual for 50-100 people to share a tent overnight. Such overcrowding and continuous close contact greatly increases the spread of respiratory infections. It has been estimated that more than one in three pilgrims will experience respiratory symptoms during their stay.⁴

The Saudi Arabian Ministry of Health has recommended that masks be used to minimise droplet spread,^{7 8} but many Muslims consider covering the face during the Hajj to be prohibited. In addition, masks need to be of a high quality and changed at least every six hours to remain effective, so general compliance with this advice is unlikely.

The Department of Health (for England) does not advise the use of masks, but frequent hand washing is recommended to reduce spread of the virus. Given the religious insistence on ritual purity before the five daily prayers and other acts of worship, this suggestion should be acceptable to most pilgrims and relatively easy to implement.⁹

Although the Saudi authorities currently recommend vaccination against influenza for pilgrims with “high risk” chronic illnesses such as pre-existing respiratory disorders, data from the United Kingdom indicate that many such high risk pilgrims remain unimmunised.¹⁰ The situation is probably far worse among the large numbers of people coming from the economically developing world. Given this fact and the risks of a pandemic originating from the Hajj, mandatory influenza vaccination for all pilgrims should be considered.¹¹ Mandatory meningococcal vaccination was introduced after a meningococcal epidemic among pilgrims and their contacts. As pilgrims already need to seek medical attention to obtain a meningococcal vaccination, this extra vaccination should not be too inconvenient and should be readily acceptable.

Neuraminidase inhibitors can reduce the duration of the illness and its spread to household contacts.¹² However, two practical difficulties need to be overcome before these drugs can be made available to pilgrims. Firstly, the high prevalence of general respiratory symptoms and the absence of state-of-the-art diagnostic testing facilities make it difficult for infected people to be identified quickly.⁵ Early diagnosis is important for treatment to be effective, so near patient testing should be more readily available. The second difficulty lies in the cost of stock piling sufficient supplies for the numbers that may be affected and the logistical challenge of ensuring that household contacts of returning pilgrims are treated promptly.

Virus surveillance studies to identify newly emerging strains are needed urgently. Currently Saudi Arabia is not among the 100 centres around the world where such structured surveillance studies are being undertaken.⁴ The World Health Organization is still developing its strategy to prevent a possible influenza pandemic. WHO must work with the Saudi authorities to minimise the risk of the influenza virus spreading among pilgrims (and the rest of us). A coherent international response will be needed to ensure that the resources and logistics are in place so that these strategies can be implemented.¹³