Reddit Chatter Signaled Virus Surge in World Cup Host City

Public health surveillance tactics in place for the FIFA World Cup identified and confirmed a gastrointestinal virus surge in a host city.

The Health Security Operations Center (HSOC) has been leading an independent and collaborative public health effort during the soccer tournament, with more than 30 partners contributing public health surveillance and data that HSOC synthesizes and sends out in daily situation reports.

One of HSOC’s communication partners is Katelyn Jetelina, PhD, MPH, creator of the widely read “Your Local Epidemiologist” newsletter that now has a listening research arm called Project Stethoscope, which has been activated for the World Cup. Jetelina’s team is triangulating data sources with social listening on platforms like Reddit and Facebook, utilizing Google data, and conducting weekly surveys to World Cup attendees and people living within 30 miles of stadiums.

“Chatter can act as an early signal of health events that are happening that traditional epidemiological systems haven’t necessarily picked up yet, or we haven’t seen yet,” Jetelina said during an HSOC press call.

Indeed, on the morning of June 10, Jetelina’s team picked up “a social listening data signal around significant chatter about gastrointestinal symptoms in the Seattle area,” she told MedPage Today. This chatter was detected on a general Reddit thread, not a World Cup-specific one. Jetelina’s team escalated this information to the larger HSOC team and wastewater partners looked at data in and around Seattle and across Washington state.

“When we looked deeper into the epidemiological data, there sure was a big wastewater signal there,” Jetelina said.

Specifically, there was a large signal for an increase in adenovirus beginning in May from one watershed in Snohomish County, which is approximately 30 minutes away from a World Cup stadium.

HSOC reported that “while this seasonal increase has occurred across multiple states in previous years, Washington’s current rise is steeper than in past years and is occurring independently of other states.” This information was escalated to Snohomish County and Washington state for their situational awareness, Jetelina noted.

The Snohomish County Health Department told MedPage Today that they were notified of an uptick in adenovirus F40/41 at a single WastewaterSCAN site, though it’s not a reportable condition and the clinical course is generally mild and self-limiting, lasting 1 to 2 weeks.

Adenovirus F40/41 is a major cause of acute gastroenteritis in children, second only to rotavirus. It has an incubation period of 8 to 10 days and infection typically presents with periodic diarrhea, low-grade fever, vomiting, abdominal pain, and mild dehydration. Transmission predominantly occurs via the fecal-oral route, and the virus is resistant to detergents, acidic conditions, and moderate heating due to its non-enveloped structure.

The county health department said they have not seen any other concerning indicators, like school or long-term care facility gastrointestinal outbreaks, and so far, syndromic surveillance has not shown any upticks related to FIFA events.

“While levels have risen, similar increases occurred last summer and in the fall, and the current signal isn’t high enough to be considered alarming,” they said, adding that this could change if levels continue to rise or if they see an increase in severe disease.

The Washington State Department of Health told MedPage Today this wastewater was collected at the Snohomish Wastewater Treatment Plant, where WastewaterSCAN also tests for hepatitis A and norovirus. As of yesterday, the wastewater surveillance testing there showed “‘high’ levels of norovirus in samples” but compared to historic levels, this reading wasn’t unusual.

“This is why HSOC was created,” Jetelina said: to use innovative sources of health intelligence data, to triangulate data sources, and to support local public health efforts. “It’s a team effort to ensure fans can enjoy the chaotic, beautiful joy that the games bring.”