1.3 Key points

  Measles is an extremely contagious viral disease found worldwide.

■  It most often affects children under 5 years of age.

■  Immunity can be acquired by contracting the disease (lifelong) or by immunisation. One dose of the vaccine administered after age 9 months confers immunity in 80 to 95% of cases.

  The case fatality rate during epidemics is between 3 and 15%.

  The group of susceptibles is composed of unvaccinated individuals and vaccination nonresponders.

■  Areas with inadequate vaccination coverage (≤ 80%) or a high birth rate are at high risk for outbreaks.

■  In the absence of outbreak response vaccination, outbreaks can last anywhere from a few weeks to several months.

  An early vaccination campaign that targets a broad age range and achieves high vaccination coverage has a significant impact on the shape of the epidemic curve.

  The decision on which groups to vaccinate is based on available epidemiological data and the resources that can be mobilised.