Disease Surveillance During a Large Religious Mass Gathering in India–The Prayagraj Kumbh 2019 Experience

Aggrawal, Vikasendu; Dikid, Tanzin; Jain, S.K.; Khasnobis, Pradeep; Choudhary, Sushma; Chandra, Ramesh; Patil, Amol; Maramraj, Kiran Kumar; Talyan, Ashok; Singh, Akhileshwar; S. Babu, Binoy; Kumar, Akshay; Kumar, Davendra; Singh, Jayanti; Kumar, Rakesh; Qadri, S.S.; Madan, Preeti; Vardan, Vaishali; Anthony Dzeyi, Kevisetue; Gupta, Ginisha; Mishra, Abhishek; TP, Vaisakh; Patel, Purvi; Kaur, Suneet; Shrivastava, Anubhav; Dhuria, Meera; Chauhan, Ritu; Singh, S.K.

BACKGROUND: Mass gathering (MG) events are associated with public health risks. During 14 January–4 March 2019, Kumbh Mela in Prayagraj, India was attended by an estimated 120 million visitors. An on-site disease surveillance was established to identify and respond to disease outbreaks. METHODS: A health coordination committee was established for planning. Disease surveillance was prioritized and risk assessment was done to identify diseases/ conditions based on epidemic potential, severity of illness and reporting requirement under International Health Regulations (IHR) 2005. A daily indicator and event-based disease surveillance was planned. The indicator-based surveillance (IBS) manually and electronically recorded data from patient hospital visits and collected MG area water testing data to assess trends. The event-based surveillance (EBS) helped identify outbreak signals based on pre-identified event triggers from media, private health facilities and food safety department. Epidemic intelligence was used to analyse data and events to detect signals, verify alerts and initiate response. RESULTS: At Kumbh Mela, disease surveillance was established for 22 acute diseases/ syndromes. Sixty-five health facilities reported 156,154 illnesses (21% of total 738,526 hospital encounters). Among reported illnesses, 95% (n = 148,834) were communicable diseases such as acute respiratory illness (n = 52504,35%), acute fever (n = 41957, 28%) and skin infections (n = 27,094, 18%). There were 5% (n = 7300) non-communicable diseases (injuries n = 6601, 90%; hypothermia n = 224, 3% and burns n = 210, 3%). Water samples tested inadequate for residual chlorine in 20% (102/521). The ICC generated 12 early warning signals: acute diarrheal (n = 8,66%), vector-borne (n = 2,16%), vaccine-preventable diseases (n = 1,8%) and thermal event (n = 1,8%) from IBS and EBS. There were two outbreaks (acute gastroenteritis and chicken pox) that were investigated and controlled. CONCLUSIONS: This on-site disease surveillance imparted a public health legacy by successfully implementing an epidemic intelligence enabled system for early disease detection and response to monitor public health risks. Acute respiratory illnesses emerged as a leading cause of morbidity among visitors. Future MG events should include disease surveillance as part of planning and augment capacity for acute respiratory illness diagnosis and management.