The number of estimated vaccinations is now nearly 5.2 million (vaccinations administered by Tuesday 27 April). Due to a programming error, an overestimation occurred in the vaccination figures. As a result, 220,000 excess vaccinations were reported on 13 April. The Coronavirus Dashboard and the RIVM weekly update will be updated today to reflect the correction. The corrected figures do not affect the progress of the vaccination programme.

Starting on Wednesday 13 April, RIVM applied a new method for calculating the estimated vaccination figures. In programming the new calculation method, an error was made that caused the number of vaccinations given by GPs and institutions since 13 April to be overestimated by about 10%. This is about 4% of the total number of vaccinations.

After the error was corrected, the programming and calculation method were also checked and validated by an external party. 

Vaccination registration system

RIVM receives vaccination data from various systems: hospitals, Municipal Public Health Services (GGDs), healthcare institutions and GP practices. The data is stored in CIMS, the national COVID-19 vaccination Information and Monitoring System. CIMS is used to keep track of key data on COVID-19 vaccination that will be important in controlling the epidemic. The GGD and hospitals consistently supply vaccination data.

Not all implementing parties provide their vaccination data to RIVM and CIMS. There could be various reasons for this: people may not have given consent for their data to be shared, consent may not have been requested, or organisations have a backlog in providing data. 

In order to arrive at the most accurate and timely estimates of how many people have been vaccinated despite this, RIVM uses programmed computer scripts. They estimate the vaccination figures based on the number of vaccines sent out for delivery, receiving parties and assumed wastage (1%), and the period in which the vaccines are administered.

Data supply

To ensure that CIMS is as complete as possible, all parties involved need to supply their data. RIVM and the Ministry of Health, Welfare and Sport (VWS) are working on a solution. RIVM is contacting as many institutions as possible with an urgent request to supply the missing data. The Minister of VWS is consulting with the sector organisations to encourage them to improve their data supply.

The correct estimates of the vaccination figures are in the weekly RIVM update published today. The figures on the Coronavirus Dashboard will also be updated today.