No 6b - 2024

Vaccination reminders not sent out for the childhood vaccination programme

Statens Serum Institut (SSI) has become aware that errors have occurred affecting the sending of vaccination reminders for the childhood vaccination programme as from late June 2023. The errors have affected both proactive reminders (sent 14 days ahead of the recommended vaccination date) and reactive reminders (sent 30 days after the recommended vaccination date if the vaccination has not been administered).

Due to an error in the IT systems employed by the reminder scheme, approx. 82,000 proactive reminder letters informing of upcoming vaccinations were not sent. The error affected reminders that should have reached the custody holders of five-year-olds who were approaching their diphtheria-tetanus-whooping cough-polio booster vaccination, and 12-year-olds who were approaching their HPV vaccination date.

Furthermore, reactive reminders were not sent in connection with approx. 44,000 recommended vaccinations in the same period. Among others, this has affected the second MMR vaccination given at four years of age.

The lacking proactive reminder letters were sent via e-Boks on 17 January 2024 , and the lacking reactive reminder letters were sent on 29 January 2024. No reminder letters were sent to children who had already received the vaccination in question.

In relation to the proactive reminder system, general practitioners may therefore experience, in the coming period, that more parents than normally request vaccination of their child, and that the children are up to 6 months older than their recommended vaccination date. Vaccination activity data show that HPV vaccination of 12-year-olds was particularly affected by the lacking vaccination reminders.

The established reminder schemes have proven effective in increasing the already high coverage of the childhood vaccination programme, and SSI is cooperating with the IT technology provider to ensure that any systematic failure to send out the electronic reminder letters in future will be detected without undue delay.

(J. Grau, L. Hallundbæk, P.H. Andersen, Department of Infectious Disease Epidemiology and Prevention)