Fourth wave feared: RIVM finds several Delta coronavirus variant clusters in Netherlands

Just days before the Netherlands is set to relax coronavirus restrictions in the Netherlands, the country's top public health organization is sounding the alarm bell over the delta coronavirus variant. New research from England determined the variant is about 64 percent more contagious than the alpha variant common to the Netherlands.

The delta variant is believed to be currently responsible for about 9 percent of coronavirus infections in the Netherlands. The RIVM said the variant will become the main coronavirus strain in the country this summer. The RIVM said this could lead to a fourth wave of infections later this year, similar to after the summer of 2020.

"This happened because travelers became infected at their holiday destination and brought the virus back to the Netherlands. This, combined with more social contacts, resulted in a further spread of the new variants in the Netherlands," the RIVM said.

Over the past two weeks, 624 people who tested positive for coronavirus had recently traveled to Spain or Portugal. Many of them were high school students celebrating the completion of their final exams. Genome sequencing of the coronavirus which infected the young people "revealed that a large part of these infections was caused by the delta variant."

The GGD municipal health service in Amsterdam has asked more of these students to come forward and get tested. Health Minister Hugo de Jonge said on Tuesday that they should get tested even without symptoms of Covid-19.

The RIVM is mainly concerned about the autumn, with the general seasonal increase of infections expected. "The more contagious delta variant could then lead to a new wave of infections, since not everyone in the Netherlands has yet been fully or partially vaccinated." In fact, the latest data from the agency showed that about 34 percent of the adult population was fully vaccinated against Covid-19 through Sunday.

"An increase in infections can lead to an increase in hospital and ICU admissions. Whether the delta variant is not only more contagious, but also more pathogenic is being investigated further," the RIVM said. Such an increase in hospitalizations is not expected in the short term.

"Coronavirus is not gone. We have to stay alert, especially on vacation," De Jonge said. He and Prime Minister Mark Rutte announced on Friday that the Cabinet would release most lockdown restrictions from June 26.

Noted virologist Marion Koopmans told Rijnmond that the Delta variant will become the dominant strain in July.