The number of people who have tested positive for coronavirus has risen for the first time in three months, according to new figures from national health institute RIVM. But experts say it is too early too judge if this is the start of another wave.

Some 9,459 people tested positive in the last week, compared to 7,088 a week earlier. The RIVM said there was no single cause for the rise. ‘We see more people with new variants. The holiday weekend could have something to do with it, or the fact that more people are getting tests ahead of a holiday,’ a spokesman told the Parool.

However, there is no telling when a new wave might hit the Netherlands, he said.

The European Centre for Disease Prevention and Control ECDC has said the rise in ‘variants of concern’ could lead to a new wave of infections this summer. In Portugal, the BA.5 variant is now dominant and has already led to more hospital admissions.

New variants are less susceptible to vaccines and declining protection from booster shots is expected to lead to more infections here as well, experts told the paper.

While the new variants are not thought to be more severe, a rise in infections could lead to more hospital admissions. A coronavirus summer wave could create problems for staffing, with numbers already stretched and the holidays in sight, they said.

Official testing figures in the Netherlands do not provide a complete snapshot of the spread of the virus because PCR testing is much less widely available and people are officially advised to test at home.

However, tests on waste water do show that there is no longer a steady reduction in coronavirus particles, the RIVM said.