overall mortality influenza-related mortality (influenza, pneumonia, respiratory and circulatory causes of death)
Conditions
Interventions
Since this is an observational study on survival of the two groups mentioned below, no other interventions were carried out apart from the vaccine or placebo administration in November 1991.
Previous
Sponsors
None
Eligibility
Inclusion criteria
Inclusion criteria: A randomized clinical trial on the efficacy of influenza vaccination in the elderly, involving 31 general practitioners in 15 practices in the southern region of the Netherlands, was conducted in the winter of 1991-1992. All persons aged 60 years or older were invited to enter the trial if they did not belong to those high-risk groups in which vaccination was recommended. At that time, age was no criterion for recommendation. In total 1838 patients (869 male, 989 female) agreed to participate. Of those who enrolled, 490 patients with heart conditions, lung conditions or diabetes mellitus were not considered to belong to the high-risk group by their general practitioner. In order to perform the new study, we complement the data of the previous trial with present information on mortality of the former participants. In specific, date and causes of death are added. In order to complete our data with additional mortality statistics the Municipal Personal Records Database (Gemeentelijke Basisadministratie, GBA) is searched by a government official to identify the former participants’ “vital status”, i.e. whether they had died, and the date of death if applicable. In case of negative findings we contact the participants’ family practice to enquire about the vital status. If this cannot be provided by the family practice (e.g. due patients’ migration), we request the Netherlands Centre for Family History (Centraal Bureau voor Genealogie, CBG) and – subsequently - an archivist of the Regional Historical Centre of Limburg (Rijksarchief Limburg) to conduct an extensive genealogical search in the national or respectively regional archives. If a search for an individual is not successful, the vital status is checked by the local municipality where the former participant has been living according to our most recent information. Search results of the family practice will be double-checked by the municipalities. Finally, using the service of Statistics Netherlands (Centraal Bureau voor de Statistiek, CBS) we will verify the dates of death that have been found, and trace back the cause of death of deceased participants up to present time. The CBS will be asked to perform this search during March 2017.
Exclusion criteria
Exclusion criteria: All former trial participants (n=1838) were included. In case of loss to follow-up, the data was censored. No participants were excluded from the analysis.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| -overall mortality -cause-specific mortality | — |
Contacts
Public ContactG.J. Dinant
University Maastricht (UM), Department of General Practice, P.O. Box 616
Outcome results
None listed