Despite free basic vaccines administered by the Expanded Programme on Immunization (EPI), there is still a fairly high death rate of children aged 0-5 worldwide due to vaccine-preventable diseases. Sub-Saharan Africa is the most affected region due to low levels of vaccination. This study analyses the effect of birth order on the immunization status of children in Cameroon, considering the contribution of cultural, economic and community factors. To do this, it uses data from the Demographic and
Health Surveys of 1991, 1998, 2004 and 2011 produced by the National Institute of Statistics with the support of UNFPA, UNICEF, the World Bank and USAID. The EPI module was administered to 3,350, 2,317, 8,125 and 25,524 children under five in 1991, 1998, 2004 and 2011, respectively. The multinomial probit model makes it possible to find that birth order has a negative and highly significant effect on the full and timely immunization of children under five and the impact increases with birth order. Moreover, the impact of birth order increases after adjusting for cultural factors. This increase indicates that, beyond the effect of birth order, cultural factors are at the root of prejudices leading to the abandonment of children. Considering children under two years of age, and vaccines taken during the first four months, the corresponding birth order effect points to the benefits of routine immunization and response campaigns in promoting immunization of children under five.
