Despite claims that people are unlikely to become infected with coronavirus outdoors, some 14 people in their 20s and 30s have picked up Covid-19 after spending time on a busy café terrace in the Frisian town of Dokkum.

The source of the outbreak has been traced out to one young man, and most of the others are thought to have become infected while sitting too close together outside, the local health board said in a statement.

Everyone found to have the virus is now in quarantine and no-one has been hospitalised, the health board said. The young man who spread the virus to others picked it up at a small gathering of friends at home in late July.

‘We do not know exactly how the virus was able to multiply but we have established that the group were not keeping far enough apart and that most infections took place on the terrace,’ the health board said. ‘This is a typical example of going out when you have symptoms. The rules have clearly been ignored.’

Dokkum mayor Johannes Kramer says officials will now step up monitoring cafes and bars. ‘The virus is not a problem happening somewhere else,’ he told local paper Leeuwarder Courant. ‘It is just round the corner.’

The infection rate in the north of the country remains far below that of the south and central areas. Nationwide, officials have identified 259 separate infection clusters but this is the first in Friesland, the paper said.

Prime minister Mark Rutte made a direct appeal to youngsters to keep to social distancing and other rules at Thursday’s press conference.

Update August 10
The health board has confirmed it cannot be 100% certain that the virus was spread outdoors, but says it considers this to be ‘very likely‘ given there was no social distancing or wind.

‘In this way, GGD Fryslân considers it as likely that the virus was spread on the terrace as in the bar, where they also were.’