Vaccination, the most cost-effective health care intervention preventing morbidity and mortality associated with vaccine-preventable diseases (VPDs), has been estimated to prevent between 2 and 3 million deaths annually. It is well established that immunisation is one of the most cost-effective and successful public health interventions in the history of mankind. In 1974 the World Health Organization (WHO) established the Expanded Programme on Immunisation (EPI), which originally provided universal vaccination against six VPDs (tuberculosis, polio, diphtheria, tetanus, pertussis and measles), to children under the age of six years. Over the next four decades, as safe and effective vaccines became available against other infectious diseases causing high global burdens of mortality and morbidity, these were incorporated into the EPI. Since it was launched in 1995, the EPI of South Africa (EPI-SA) has closely followed WHO guidelines, and currently provides free immunisation against 11 VPDs, having added vaccines against five VPDs to the traditional six, these being vaccines against hepatitis B (1995), Haemophilus influenzae type b infection (1999), invasive pneumococcal disease (2009), rotavirus diarrhoea (2009) and cervical cancer (2014). EPI-SA has achieved many successes, with neonatal tetanus being eliminated by 2002; no wild-type poliovirus transmission reported since 1989; >60% reduction in hepatitis B virus (HBV) prevalence in those born after 1995; >40% reduction of pneumococcal disease in all age groups since 2009; and a 60% reduction in rotavirus-associated hospitalisations since 2009. Furthermore, since its inception EPI-SA has enjoyed tremendous political and financial support from the national treasury, which has allowed it to be an African leader in introducing new and underutilised vaccines. For example, South Africa was the first African country to introduce into its EPI (a) the pneumococcal conjugate vaccine; (b) the rotavirus vaccine; and (c) a hexavalent vaccine against diphtheria, tetanus, pertussis, polio, Haemophilus influenzae type b infection and hepatitis B.

As new vaccines become available and are recommended by the WHO, countries face many challenges in introducing these vaccines into their existing immunisation programmes. These challenges include decision-making and prioritisation of these vaccines against other competing health programmes; addressing strengths and weaknesses in the immunisation programme; managing more complicated vaccination schedules; developing multi-year plans to ensure sustainable use of the new vaccines; integration of these vaccines in the broader context of health systems; and building and maintaining public trust in these vaccines. Thus, continued and increased efforts are required not only to accelerate action to vaccinate children against VPDs, but to reach and maintain high vaccination coverage.