Active Surveillance for Adverse Events After a Mass Vaccination Campaign With a Group A Meningococcal Conjugate Vaccine (PsA-TT) in Mali

New vaccines, such as those against malaria and dengue, are being developed for use primarily in low-resource countries. Emerging manufacturers provide an increasingly large volume of vaccine products to global programs that will never reach industrialized country markets [1]. Concerted efforts are being made to reduce the time from availability of new vaccines, such as rotavirus and human papillomavirus vaccines, to their introduction in developing countries [2]. The current vaccine pipeline includes products based on complex technologies such as genetic recombination or novel adjuvant systems, and theoretical concerns about the safety of new products indicate the need for postlicensure safety monitoring [3, 4]. Public concern about vaccines can also adversely impact vaccination programs, and having systems in place to monitor safety can help address these concerns with reliable data [5]. Most low-income countries do not have the resources or infrastructure in place for postlicensure safety surveillance. PsA-TT is a lyophilized conjugate vaccine developed for use in the meningitis belt of sub-Saharan Africa and manufactured by the Serum Institute of India Ltd [6]. Clinical trials in India and West Africa included nearly 12 000 individuals aged 1–29 years, although at the time of licensure <5000 individuals had received the vaccine [7–9]. The World Health Organization (WHO) Global Advisory Committee on Vaccine Safety reviewed clinical trial data and concluded there were no significant safety issues identified from the trials [10], but the committee recommended vaccine safety surveillance postlicensure in countries introducing the vaccine [11, 12]. PsA-TT was initially rolled out in select districts in Burkina Faso, Mali, and Niger in September 2010 with mass vaccination campaigns targeting all individuals 1–29 years of age. The public health benefits of PsA-TT have already been demonstrated by a sharp decline in reported cases of meningococcal disease in the countries where it has been introduced [13–15]. The purpose of this study was to assess the safety of the PsA-TT vaccine in people aged 1–29 years in Mali. Previous studies of PsA-TT utilized passive surveillance systems to assess vaccine safety. Here, we report the results of a novel active vaccine safety surveillance system that we piloted during a rollout campaign in Mali.