Middle East Respiratory Syndrome (MERS-CoV) first emerged in Saudi Arabia in 2012 and has since infected 681 people, of whom 204 have died. It has hop-scotched around the Middle East and appeared in at least eight countries farther afield, but the bulk of cases remain concentrated in the Kingdom.
Some cases may have been transmitted through person-to-person contact, which suggests there could be a particular risk wherever people gather in great numbers. However, no sustained community transmission has been detected in the general public. Most cases appear to be either new introductions of the virus into people or through hospital-based outbreaks.
Saudi Arabia draws millions of pilgrims to its holy places every year, from both within its borders and around the globe. Peak times for worshippers to visit include the holy month of Ramadan, which begins on June 29th this year, and in October of this year the Hajj—an event that drew three million visitors in 2012.
With the number of MERS-CoV cases increasing, the Bulletin spoke with Maurizio Barbeschi, a scientist at the World Health Organization, about the virus and the risks posed by mass gatherings. Barbeschi leads the organization’s Preparedness, Mass Gatherings and Deliberate Events group, which provides strategic guidance on dealing with high-visibility and high-consequence events. He is a contributor to “Mass gatherings medicine: international cooperation and progress,” a new report published in The Lancet.
Barbeschi answered the Bulletin’s questions with support from his team at WHO, including Medical Officer David Brett-Major and Technical Officers Nicolas Isla and Sascha Meijers.
Saudi Arabia will draw millions of pilgrims this year, during Ramadan in July and the Hajj in October. How can such mass gatherings affect the spread of viruses like the one that causes MERS?
Mass gatherings can be wonderful events, but also may give any potential infection the opportunity to spread. People are close to one another, often in confined spaces, over a prolonged period of time. Sometimes they change their eating, drinking and hygiene habits. And mass gatherings attract many international participants who could potentially export an infection to their home countries.
To date, only limited, non-sustained human-to-human transmission of MERS-CoV has been observed. Performing the Umrah—pilgrimage to Mecca at any time—or the Hajj—pilgrimage to Mecca at an annual fixed time on the Islamic calendar—does not appear to have been a significant risk factor for infection since MERS-CoV was first detected in 2012. However, given the significant increase in recent infections, each mass gathering’s health risks should be viewed in light of the evolving outbreak.
Can you give past examples of mass gatherings that contributed to the spread of viruses?
A number of scientific studies conducted during and after the 2008 World Youth Day in Sydney, Australia, found that participants from overseas introduced influenza during a non-seasonal period. During the celebrations, 223,000 pilgrims from 170 countries attended the mass religious gathering over a five-day period. Some events were attended by an estimated 400,000 persons. An influenza outbreak occurred among participants and likely resulted in increased influenza in Australia with some imported strains. Crowded accommodation conditions and low immunization rates were likely factors.
There was also an influenza outbreak that occurred during the Salt Lake City Winter Olympics in 2002, with more than one third of infections appearing in athletes. Three clusters in particular were identified—among law enforcement personnel living in close proximity to one another, among 12 national team members who trained together and were staying at a common location, and among eight athletes participating in one sport with common training venues.
And, there was a 2010 outbreak of measles found to have originated in Taizé, France. The area is home to the Taizé Community, an ecumenical monastic order and one of the most important sites of Christian pilgrimage. Each summer the community attracts up to 5,000 pilgrims. In September and October of 2010, primary measles cases were found in 13 people in Germany, all of whom had attended meetings in Taizé.
What have you learned from these past events?
First, that continuous risk assessment should be the backbone of any public health planning for a mass gathering.
Second, that while mass gatherings may pose significant challenges, they also present an opportunity to have a positive long-term impact in the form of enhanced public health services, improved hospital and emergency services, a healthier living environment, and enhanced health awareness.
Planning for a mass gathering generally involves the whole government. Therefore, it is of paramount importance that health has a seat at that planning table and that there is interoperability between sectors and their plans and risk assessments.
Finally, participants should be provided with travel and health advice on recommended vaccinations and precautions to be taken before the event. WHO routinely generates and publishes such advice on its International Travel and Health website. Individual country public health agencies also generate related advice.
Mass gatherings are increasing in size and international participation. How big and diverse are events today compared to those in the past?
In general, the size of mass gathering events, especially ones like the Olympics and the FIFA World Cup, has increased in the past 30 years. At the 1996 Olympic Games in Atlanta, 8.3 million tickets were sold, a record at the time. At the 2012 London Olympics, 10 million were sold. The year 1994 still holds the record for attendance at a FIFA World Cup, but the 2006 and 2010 World Cups saw the second- and third-greatest number of participants in history with more than three million people each.
Although it is more difficult to measure, it also appears that mass gathering events are attracting a more diverse set of participants. Data collected during the Hajj shows that the proportion of pilgrims from outside Saudi Arabia increased by almost 30 percent between 1996 and 2006. Total numbers of pilgrims were down in 2013, in part thanks to risk communication and steps taken by the Saudi government to reduce the number of persons at risk for MERS-CoV infection during the pilgrimmage. Of the two million pilgrims in 2013, though, some 70 percent were foreign, hailing from more than 180 countries, and the long-term trend for total numbers attending the Hajj is upward.
But we should not focus only on the largest events; there are also many medium-sized events all over the world that introduce risk, create public health opportunities, and have significant international participation.
What are some of the challenges that mass gatherings present to health authorities?
The strain on health systems may come from having to support both the local population and the transient population during the period of the event. This may be true for the broad range of services that health systems provide, for example, acute and chronic care.
Mass gatherings can also potentially increase the risk of transmission of infectious diseases between countries. Participants from overseas could potentially import infectious diseases into the host population and vice versa.
The risks are diverse. There may also be an increased risk of accidents and mass casualty events—such as stampedes—as well as violence and terrorist activities, all demanding greater health surveillance and response systems than local authorities may be accustomed to providing. Food and waterborne disease is almost always a concern, and in some locations heat injury and dehydration must be considered.
In addition, it’s difficult to coordinate and share information with participants from a large number of regions, nations and cultures that may not share a common language.
Governments’ reputations can also be put at risk, especially at events with heavy media coverage, which can be politically sensitive. A well-managed mass gathering can boost a government’s reputation and trust with people in a community, particularly if the event is seen to have a lasting positive impact.
What should Saudi health authorities do to combat the spread of MERS-CoV during the Hajj?
WHO is regularly updating its travel advice on MERS-CoV for pilgrimages. Much of the guidance will be the same as last year, and will focus on effective communication on how to lower risk. Pilgrims should be advised that pre-existing major medical conditions—such as diabetes, chronic lung disease, or immunodeficiency—can increase the likelihood of severe illness. Washing hands often with soap and water, adhering to good food safety practices, maintaining good personal hygiene, and avoiding unnecessary contact with animals should also be encouraged.
WHO does not recommend the application of any travel or trade restrictions or entry screening. All countries should ensure that routine measures are in place for detecting and assessing ill travelers entering the country, as well as for safe transportation of symptomatic travelers to hospitals or clinics.
In terms of planning for the events themselves, the government should undertake a risk assessment—in partnership with local, national and international public health authorities and experts—taking into account the latest science and epidemiological situation of the virus, the particular characteristics of the gathering, and current capacity for dealing with any risks.
Are there other upcoming mass gatherings around the world that you worry about? What are they?
All mass gatherings can potentially pose challenges as well as opportunities for public health. While we often focus on the negative, mass gathering events can be a great opportunity to improve public health within the host community and leave a positive legacy.
An analysis of the 2010 FIFA World Cup in South Africa identified five main public health legacies. These included the transfer of knowledge; improved co-operation and communication; the potential for increased training and expertise in human resources; improvements in processes and available resources; and improved confidence within the country that it can host future mass gatherings. Indeed, senior health officials in South Africa informed me that health lessons from the World Cup are now used in all aspects of the public health system as well as at other mass gatherings. Recent examples include former President Nelson Mandela’s funeral in December and the Africa Cup of Nations, also last year, which South Africa agreed to take on at short notice after war-torn Libya was forced to pull out of hosting the championships.
What about mass gatherings caused by natural disasters or political unrest? How do they interact with viral spread?
Natural disasters and political unrest can create unplanned mass gatherings, such as refugee camps or emergency shelters. Unsurprisingly, these types of settings can create enormous public health challenges. Viral, bacterial and parasitic diseases all have the potential to spread in crowded settings with poor sanitary conditions and a lack of safe food and water.
At the moment there is particular concern over wild poliovirus, which is spreading in areas currently facing political unrest and a growing number of refugees—including in Afghanistan and Pakistan, parts of Sub-Saharan Africa, and Syria. From January 2012 through early 2013, international transmission of wild poliovirus had nearly ceased, so its resurgence constitutes an alarming reversal—at the end of April, WHO declared the situation a public health emergency of international concern.
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