964 people got COVID-19 after an outdoor music festival, despite compulsory negative tests, vaccines, or other proof of immunity

• 964 people who attended a Dutch outdoor music festival tested positive for the coronavirus.
• The festival did not impose social distancing, arguing that its screening procedures were enough.
• Information on the severity of the cases was not available.
• See more stories on Insider's business page .

Nearly a thousand people tested positive for the coronavirus after attending a two-day outdoor festival in the Netherlands on the weekend of July 3.

Figures from health officials in Utrecht indicated that 448 were exposed during the first day of the festival, and 516 the second day. The figures were reported by Algemeen Dagblad , a Dutch daily newspaper.

More cases are likely to be identified in the coming days, one official said, the online news portal Dutch News reported.

Information about whether the festivalgoers developed symptoms from the infection - and if so, how badly - was not immediately available.

Among vaccinated people who developed "breakthrough" infections, symptoms are typically milder .

The Verknipt festival, which attracted about 20,000 visitors, was one of the first after the country relaxed its COVID-19 measures on June 26, local media RTV Utrecht reported.

Before entry, visitors were asked to prove that they had been vaccinated, had recovered from COVID-19 recently, or had tested negative for COVID-19.

Posts from the festival show attendees in close proximity, as can be seen in this tweet from the mayor of Utrecht, Sharon Dijksma, who went on July 3.

A tweet from Spanish DJ Fatima Hajji showed a similar scene.

The government says it went too fast

On Monday, Dutch Prime Minister Mark Rutte apologized for lifting restrictions too soon, calling it a "miscalculation," Euronews reported.

"What we thought was possible turned out to be wrong in practice. We made a miscalculation, we are disappointed about it and we apologise," he said.

The government reimposed restrictions on nightlife two weeks after lifting them, and canceled all events with large crowds until August 14, The Irish Times reported.

Data from the Dutch Institute of Public Health indicated that cases in the Netherlands have shot up, reaching almost 52,000 new reported COVID-19 infections on the week of July 6.

The figure was five times the number reported the previous week. Of the infections that could be traced back to the source, 37% happened in the hospitality industry, the country's institute of public health found, ABC News reported.

Late last month, 180 people were infected at a "covid-free" party attended by 800 people in a nightclub in Enschede, in the eastern Netherlands, Insider's Mia Jankowicz reported.

In spite of the rise in cases, COVID-19 hospitalizations stayed low, with 60 new hospital admissions in the week of July 6, of which 12 required intensive care, official data showed.