The Capture-Recapture Method in the Analysis of a Measles Epidemic in the County of Cluj, Romania

Abstract

Aim: Measles is an infectious disease that has been proposed to be eliminated, but epidemics continued to appear mainly due to unvaccinated persons who refused to be vaccinated. The aim of our study was to estimate, using the capture-recapture method, the real number of cases that existed in a measles epidemic which evolved in the Cluj County’s population. Material and Method: A survey to compare the cases of measles that were declared to the Cluj County Public Health Authority during the 1993 epidemic, with those registered in the medical records from Family Doctors’ Offices, was conducted between February and March 1994. Descriptive statistics for the characterisation of non-normal distributed samples were performed using XLSTAT software. Results: In the survey, two samples were constituted, the first sample comprised of declared cases (1,404 cases), and the second sample comprised of the field-identified cases (2,383). The monthly cases’ in the samples were not different (Mann-Whitney upper-tailed test), with a cold period seasonality. For the field-identified sample, 1,667 cases were undeclared and 716 were declared and identified (“recaptured”) in the field investigation. The estimated number of cases at the Cluj County level was 4,673 cases, of which the declared ones represented 30% of all cases. Conclusion: The capture-recapture method is an easy methodology to apply, that can indicate the magnitude of an epidemic by the estimated number of cases in a specific time period and can also provide some details regarding a disease’s epidemiological characteristics.