National statistics agency CBS and public health institute RIVM say they have not yet been able to establish the reason for the large number of excess deaths during the third coronavirus wave, which are unlikely to be down to the virus.

A cause of death analysis puts the coronavirus death toll over 2020 and 2021 at around 40,000, amounting for most of the excess deaths in the first two waves. But in the third wave, 11,300 more people died than would have been expected, and only 7,900 of them were down to coronavirus.

The cause of death in the remaining 3,400 cases remains unclear and cuts across all age groups though it is biggest in the 65 to 80 category. Nursing home residents amounted for 1,000 of the unexplained deaths.

The research was carried out on the request of MPs, because the number of excess deaths far exceeded the number of people dying from coronavirus in the second half of the year.

The RIVM said the results showed that vaccination offered good protection against dying from coronavirus and did not increase the risks of dying from other causes.

Of the 166,000 death certificates studied by the researchers, just 162 listed vaccination as a possible contributing factor but they did not go into enough details to allow conclusions to be drawn, the RIVM said.

At the same time, further research is needed to establish what caused the high number of excess deaths in the second half of 2021.

Hypotheses including the delay in treating some illnesses because hospitals were too full, the failure to get treatment at all and the pressure that healthcare workers were operating under, the agencies said.