Belgium has been cited by the UK health secretary, Matt Hancock, as a model for getting coronavirus under control – just as its public health body recorded a 15% rise in the number of daily infections compared with the previous week.

Despite a dip in the number of new infections in August, after a tightening of rules by the Belgian prime minister, Sophie Wilmès, the most recent data suggests the country’s success may be short-lived as people return to work and school.

An average of 509.7 people a day have tested newly positive during the past seven days, according to the latest figures by from Belgium’s scientific institute for public health.

Thursday marked the fifth successive day that the number of people newly infected rose.

Hospital admissions are also up. Between 3 to 9 September, an average of 20.6 new admissions per day was recorded, an increase from 16.7 the week before.

Hancock had praised Belgium as he sought to justify strict new laws on social gatherings in England, including the so-called rule of six people, limiting the size of social groups.

The health secretary said the UK was learning from the experience of other European countries that had recorded an increase in coronavirus infections in recent months.

“Some of those countries have then got that second wave under control,” Hancock said. “If you look at what’s happened in Belgium, they saw an increase and then they’ve brought it down, whereas in France and Spain that just hasn’t happened.”

Belgium had a sustained decrease in the number of people recorded as being newly infected in August, after the government responded to a worrying spike the previous month.

A gradual lifting of social restrictions was halted by the government with the order that each household would only be allowed to meet and have close contact with five other adults from outside their household rather than 15, as had been previously permitted. The so-called social bubbles were to remain the same for a month.

Indoor events were also limited to 100 people or 200 outdoors, down from 200 and 400 respectively. The wearing of face masks in public was made obligatory.

But despite those measures, infections have since risen. Analysis by the Flemish Agency for Care and Health of contacts and sources of contamination, published on Thursday, has suggested a direct link with the start of the school year and the resumption of work after the summer holidays.