The burden of measles in sub-Saharan Africa can be reduced to very low levels by means of appropriate strategies, resources, and personnel.

As polio eradication inches closer, the absence of poliovirus circulation in most of the world and imperfect vaccination coverage are resulting in immunity gaps and polio outbreaks affecting adults. Furthermore, imperfect, waning intestinal immunity among older children and adults permits reinfection and poliovirus shedding, prompting calls to extend the age range of vaccination campaigns even in the absence of cases in these age groups. The success of such a strategy depends on the contribution to poliovirus transmission by older ages, which has not previously been estimated. We fit a mathematical model of poliovirus transmission to time series data from two large outbreaks that affected adults (Tajikistan 2010, Republic of Congo 2010) using maximum-likelihood estimation based on iterated particle-filtering methods. In Tajikistan, the contribution of unvaccinated older children and adults to transmission was minimal despite a significant number of cases in these age groups [reproduction number, R = 0.46 (95% confidence interval, 0.42-0.52) for >5-y-olds compared to 2.18 (2.06-2.45) for 0-to 5-y-olds]. In contrast, in the Republic of Congo, the contribution of older children and adults was significant [R = 1.85 (1.83-4.00)], perhaps reflecting sanitary and socioeconomic variables favoring efficient virus transmission. In neither setting was there evidence for a significant role of imperfect intestinal immunity in the transmission of poliovirus. Bringing the immunization response to the Tajikistan outbreak forward by 2 wk would have prevented an additional 130 cases (21%), highlighting the importance of early outbreak detection and response.epidemiology | infectious diseases | mathematical modeling T he Global Polio Eradication Initiative (GPEI) has achieved >99% reduction in the global annual incidence of poliomyelitis since the program began in 1988, and in 2012, just three countries were yet to interrupt wild poliovirus transmissionAfghanistan, Pakistan, and Nigeria-and 223 poliomyelitis cases were reported, the lowest in history (1). However, the absence of wild poliovirus transmission from most of the world, together with long-standing suboptimal vaccination coverage, has created cohorts of susceptible children and adults. As a result, an increased number of polio outbreaks affecting older children and adults have occurred in countries previously free of wild poliovirus (2-6). These outbreaks have significantly raised the cost of the GPEI and are a major challenge to achieving the goal of stopping all transmission by end-2014.It has also become clear that intestinal immunity to poliovirus wanes over time, allowing individuals vaccinated with oral poliovirus vaccine (OPV) to become reinfected and shed poliovirus (7). Therefore, older children and adults could theoretically contribute to wild poliovirus transmission without developing poliomyelitis. The World Health Organization (WHO) has recommended vaccination of older age groups as a standard for outbreak response (8). In addition, the recent GPEI strategic...

Highlights GVAP provided a comprehensive and coherent global framework for immunization. Much progress was achieved under GVAP, although most GVAP goals will not be met. GVAP was perceived as top-down, with too little consideration of country context. GVAP was only partially implemented, and it had limited levers to influence country actions. Many targets were seen as unrealistic, particularly in the absence of additional funding. Lessons learned from GVAP can inform the Immunization Agenda 2030.