Estimation of the basic reproduction number of measles during an outbreak in a partially vaccinated population

J Mossong1, C P Muller

  • 1Department of Biological Sciences, University of Warwick, Coventry, UK.

Insights

A 1996 measles outbreak in Luxembourg highlighted the critical need for high vaccination coverage. To prevent major outbreaks, especially in schools, vaccination rates must exceed 90%.

Area of Science:

  • Epidemiology
  • Public Health
  • Immunization

Background:

  • Measles outbreaks pose a significant public health risk, particularly in school settings.
  • Understanding transmission dynamics and vaccine effectiveness is crucial for outbreak control.

Purpose of the Study:

  • To analyze a measles outbreak in northern Luxembourg from March to July 1996.
  • To estimate vaccine coverage, vaccine efficacy, and the basic reproduction number (R0) during the outbreak.
  • To determine the minimum vaccination coverage required to prevent major measles outbreaks in school environments.

Main Methods:

  • Serological confirmation of suspected measles cases.
  • Questionnaire-based surveys to estimate vaccine coverage in primary schools.
  • Calculation of vaccine efficacy and basic reproduction number (R0) using outbreak data and survey results.

Main Results:

  • 110 measles cases were reported, primarily linked to two primary schools.
  • Estimated vaccine coverage was 70% and 76% in the affected schools.
  • Vaccine efficacy was calculated at 94.6%, with estimated R0 values of 7.7 and 6.2.
  • Minimal vaccination coverage required to prevent major outbreaks was estimated between 88.3% and 91.6%.

Conclusions:

  • High vaccination coverage, exceeding 90%, is essential for preventing major measles outbreaks in school settings.
  • The study reinforces the importance of robust immunization programs to maintain community immunity.
  • Effective measles control relies on achieving and sustaining high vaccine uptake rates.