On August 9, more than 2 million Muslims converged on Mecca, Saudi Arabia, to take part in this year’s Hajj pilgrimage. The Hajj is one of the central pillars of the Islamic faith, an homage to the last pilgrimage of the Prophet Muhammad and a requirement for any able-bodied Muslim with the means to afford the journey once in their life. In a previous Outbreak Thursday post, we discussed how the 5-day mass gathering poses a complex public health challenge in terms of managing increased risk of communicable disease transmission due to the large crowds of travelers from around the world. The Hajj has faced various outbreaks in the past, including meningococcal disease, gastrointestinal diseases, pneumonia, and influenza. Research indicates that pilgrims may also be at elevated risk for other diseases such as hemorrhagic fevers, arbovirus infections, and vector-borne protozoan infections (eg, leishmaniasis). In order to address these continuing risks during the annual gathering, the Saudi Ministry of Health (Saudi MOH) has deployed a combination of traditional and innovative disease surveillance, prevention, and control measures. This week, Outbreak Thursday will take a closer look at some of the newer efforts, including Saudi Arabia’s new Health Early Warning System

Awareness & Education

The first step toward preventing disease transmission at the Hajj is educating the pilgrims on infectious disease risks and appropriate protective measures. The Saudi MOH published a comprehensive guide for pilgrims with health information related to Hajj attendance, titled “For a Healthy Hajj.” This guide includes preventive measures that pilgrims can take to avoid getting sick, with targeted messaging for diseases that have caused outbreaks in previous years, special considerations for those with chronic health conditions, and other useful health-related information. In addition, Saudi officials coordinated with other countries to implement awareness-raising campaigns regarding health risks and associated preventive practices before and during the Hajj. National and international health agencies, such as the US CDC and the European CDC, also posted health alerts and other resources with precautionary measures for travelers, including recommendations for pilgrims to consult a physician specializing in travel medicine prior to departing and to practice enhanced hygiene measures during their trip. 


Saudi officials expanded Hajj immunization recommendations and requirements since our last post in order to further reduce the risk of outbreaks of vaccine preventable diseases during the event. In 2017, only the meningococcal vaccine was required for pilgrims arriving from other countries. Saudi Arabia now requires yellow fever vaccination for travelers from certain countries in Africa and Latin America and polio vaccination from travelers arriving from the Saudi MOH’s list of targeted countries as well as meningococcal vaccination for all travelers. Certificates of vaccination are required at ports of entry and during the visa application process to attend the Hajj. Additionally, the Saudi MOH recommends the seasonal influenza and MMR vaccines for all pilgrims, but they are not required. Pilgrims traveling from within Saudi Arabia are required to have the meningococcal and seasonal influenza vaccines as well. 

Last year, Saudi MOH statistics showed that pilgrims were largely heeding these recommendations, with field hospitals and clinics reporting that 96% of patients were vaccinated against yellow fever, 87.5% vaccinated against polio, and 80% vaccinated against meningitis. 

Deploying Health Personnel & Preparing Facilities

Saudi officials also increased the number of health personnel offering free care in order to ensure access to treatment for any ill pilgrims as well as increase the likelihood of identifying suspected cases. This year, 30,000 health professionals were deployed to provide care to Hajj pilgrims, and reported response times to health-related incidents have ranged from mere seconds to 20 minutes. Personnel came from a variety of disciplines and provided care via a comprehensive network that included hospitals, health centers, mobile clinics, ambulances, and medical evacuation by air, if necessary. In terms of facilities, 25 hospitals, 156 health centers, and 5,000 beds were prepared to provide care for suspected cases of infectious diseases and establish capacity for a potential surge in admissions. 

Expanding Surveillance

Saudi Arabia already has routine passive surveillance for infectious diseases in place year-round, for which facility data is reported to the MOH via local public health authorities and regional public health directorates. This surveillance system has demonstrated effectiveness during previous outbreaks of measles (2012-13) and scabies (2015) in the country. Saudi Arabia’s routine disease surveillance system also received a score of 3.75 out of 5 as part of their Joint External Evaluation.

In 2018, Saudi officials introduced the Health Early Warning System, an event-based, syndromic surveillance system that supplements existing surveillance systems used during the Hajj. During its pilot year, 8 hospitals and 25 primary healthcare facilities in Mina and Muzdalifah participated in implementation and monitoring. Data collected electronically from medical records at these facilities was compared with existing reporting systems to identify patterns and detect disease threats such as acute febrile illness, respiratory disease, hemorrhagic fever, clusters of neurological symptoms, gastrointestinal illness, heat-related illness, and other conditions. This system is linked to the general public health command center, which can mobilize a rapid response team to verify suspected incidents and respond if necessary. Automated reporting of syndromic data is designed to provide near-real-time surveillance capabilities, which can decrease the time between cases seeking care and authorities detecting and responding to an event. Research has found that reducing the delay before initiating response activities can substantially increase the likelihood of successfully containing outbreaks before they become regional epidemics or pandemics. 

The Health Early Warning System was expanded in 2019 to include 17 hospitals and 96 health facilities in Mecca, Madinah, Mina, Arafat, Mozdalefah, and other areas in the vicinity of Hajj activities. Additionally, a new technological pilot program was introduced this year, which involves wearable smart cards issued to 25,000 pilgrims by the Ministry of Hajj and Umrah. These cards are outfitted with a location tracker, allowing service providers to know the exact location of the wearer at all times and provide assistance quickly when requested. These cards also store pilgrims’ personal information, health status, residence, and Hajj tour details. Paird with the Health Early Warning System, the smart card pilot program could provide rapid geographic and health information about pilgrims, which could enable healthcare providers to more readily respond to health emergencies.

Benefits of Existing Measures & Remaining Gaps

Awareness campaigns and immunization requirements for the Hajj implemented by the Saudi MOH are mitigating the risk from infectious diseases. Increased staffing and facilities for patient care provide surge capacity in the event of an outbreak or other health emergency. The new surveillance initiatives will also hopefully increase sensitivity to infectious disease events during the Hajj and reduce delays in initiating outbreak response operations. 

Despite these initiatives, however, gaps remain in the Saudi outbreak prevention, preparedness, and response plans for the Hajj. While increased healthcare personnel and bolstered facilities provide surge capacity, there was little mention of enhancing infection control standards or stockpiling supplies in preparation for an outbreak of MERS or other diseases that can spread readily in healthcare settings. The new Health Early Warning System and smart card pilot programs are innovative additions to existing surveillance programs, but their major limitation is their reliance on individuals seeking care or reporting illnesses to healthcare providers. Some diseases can be transmissible while the patient is asymptomatic (eg, measles), and some individuals experiencing milder symptoms may be contagious without feeling the need to seek medical care (eg, for influenza or gastrointestinal diseases). These individuals could potentially infect a number of others without being recognized by syndromic surveillance systems, so more traditional public health capabilities, including contact tracing and active disease surveillance, remain critical components of outbreak preparedness and response.


Saudi Arabia has steadily increased its efforts to implement disease prevention and control measures during the Hajj in order to mitigate infectious disease risk for the millions of pilgrims that attend each year. It remains to be seen whether new systems, such as the Health Early Warning System and smartcard pilot program, or expanded mandatory vaccinations will impact infectious disease incidence in future Hajj pilgrimages. Visitors from all over the world remaining in prolonged close contact with others provides conditions that could result in the rapid international spread of disease, particularly as pilgrims return home, but Saudi health officials continue to expand their efforts to prevent these events from happening.

Outbreak Observatory aims to collect information on challenges and solutions associated with outbreak response and share it broadly to allow others to learn from these experiences in order to improve global outbreak response capabilities.


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