Impact of New Childhood Vaccines

228 March 2014, Vol. 104, No. 3 (Suppl 1) Rationale for pneumococcal conjugate vaccine and rotavirus vaccine introduction into public immunisation programmes While progress has been made in preventing deaths due to some of the vaccine-preventable diseases (e.g. measles deaths reduced from 535 000 in 2000 to 139 000 by 2010), a greater proportion of vaccine-preventable deaths is now attributed to diseases for which there are under-utilised and/or newly developed vaccines, such as those against pneumococcal disease and rotavirus. Although these vaccines are widely used in developed and well-resourced countries, their use in middleand lower-income countries has remained limited, mainly owing to the high costs of the vaccines. Worldwide it was estimated that pneumococcal disease was responsible for 14 million severe cases and 830 000 deaths in 2000, and that there were 7 million severe cases of rotavirus diarrhoea and 453 000 deaths in 2004. Significant declines in severe disease and/or mortality from these pathogens have been demonstrated in countries where the newer vaccines were introduced into public immunisation programmes. In the absence of targeted vaccination, rotavirus remains the most common cause of severe diarrhoea (associated with 28% of cases) and Streptococcus pneumoniae is still responsible for a high proportion (18.3%) of cases of severe pneumonia. In 2007, the World Health Organization (WHO) recommended that countries with under-5 mortality rates of >50/1 000 live births, and with a high prevalence of HIV or conditions that increase the risk of pneumococcal disease, should prioritise the introduction of the 7-valent pneumococcal conjugate vaccine (PCV-7) in their national immunisation programmes. Similar recommendations for rotavirus were subsequently issued. These global recommendations were premised in part by pivotal studies that had been undertaken in South Africa (SA). These included a study on a 9-valent PCV in which vaccine efficacy was established against vaccine-serotype invasive pneumococcal disease in HIV-uninfected (83%) and HIV-infected children not on antiretroviral therapy (ART) (63%), as well as against pneumonia in the first 2 years of life. Also, a vaccine efficacy study on rotavirus vaccine (RV) observed 73% protection against rotavirus-associated severe diarrhoeal disease in the SA setting, with its high prevalence of HIV infection. Although the efficacy study on RV was not specifically powered to evaluate for protection in HIV-infected children, the immunogenicity and safety of RV in this group had been established in a separate SA study.