One person responsible for 180 coronavirus cases in one night at Enschede club

The coronavirus outbreak at the Aspen Valley nightclub in Enschede on June 26 that resulted in 180 people contracting the coronavirus can be traced back to one person, an investigation from the GGD Twente showed. Other factors also facilitated the widespread of the disease on that night.

“There are strong indications there was one person infected with the SARS-CoV-2 coronavirus present who caused the remaining infections”, said Dr. Sanne Mensink of the GGD in a statement. Attendees were required to show proof of vaccination or negative coronavirus test upon entry.

“One person infected with the virus can spread the disease to dozens, if not a hundred, other people. This can happen due to a combination of different factors”, Mensink said. Such circumstances include that people in nightclubs tend to talk louder in order to be heard over the music and ventilation is not always sufficient in indoor areas. Additionally, the Delta variant is more contagious than previous mutations of the coronavirus.

The party where the outbreak occurred took place on June 26, the same day the Cabinet loosened coronavirus restrictions. This meant that nightclubs were able to reopen their doors for the first time in over a year. The first positive coronavirus test from a person who attended Aspen Valley nightclub on that night was reported on June 30. Ultimately, 180 out of the around 800 people who were present contracted the viral infection.

The GGD said it worked with a variety of stakeholders on its "extensive source and contact research" and additional research into the circumstances that night. "This concerns an extensive laboratory analysis of the variant, a visit to the location and a ventilation study."

The nightclub itself participated in the study, as did the municipality of Enschede. The findings were shared with them and the RIVM.

"We still don't know everything about the cause of major outbreaks. These studies have given us the opportunity to gather a lot of valuable information for the fight against the virus," said Reinier van Broekhoven, who heads the coronavirus department at GGD Twente. "It is good to see how everyone has contributed from their own role in recent weeks and wants to learn from this outbreak."