Improving rotavirus vaccine adoption in low- and middle-income countries

ust over a decade ago, concerns regarding vaccine-re-lated risks led to the demise of the first rotavirus vac-cine to enter the market. Licensed in the US in 1998, RotaShield was withdrawn voluntarily in 1999 by its man-ufacturer, Wyeth, when it was found to be associated with an increased risk of intussus-ception, a potentially serious and occasionally fatal intestinal obstruction estimated to occur in one case per 10 000 infants given the vaccine(1). This deci-sion was a compelling and con-troversial one for global health: In seeking to avert rare but seri-ous adverse events caused by the vaccine in the US, it never-theless vexed efforts to address the staggering burden of diar-rheal disease in developing countries. In other words, the potential benefits of a vac-cine that might have prevented most of the approximately 500 000 deaths and 1.5 million hospitalizations of infants and young children in Africa and Asia each year caused by rotavirus gastroenteritis (RGE) were overshadowed by risks that some commentators have argued ought to have paled in comparison (2). In 2011, the rotavirus vaccine landscape has changed with two licensed vaccines recommended by the WHO Strategic Advisory Group of Experts (SAGE) on Immunization, available for adoption into national immunization pro-grams, and several other vaccines in the development pipe-line. And yet, the stark reality is that as of July 2011, only 24 countries (10 of which are low- and middle-income countries (LMICs), Sudan being the most recent) and no low-income countries had adopted rotavirus vaccines into their immunization programs(3), leaving millions of chil-dren without access to the crucial tool to prevent RGE-associated morbidity and mortality.The barriers to uptake dotting the landscape have also changed. Safety remains an issue of some concern, particularly in light of emerging data from some post-marketing studies of the current-ly available rotavirus vaccines that suggest caution. However, considerations of efficacy and cost are assuming more promi-nence, which is appropriate as each barrier needs to be carefully assessed by decision-mak-ers weighing benefits versus risks. Indeed, the ability to overcome other potential barriers – such as the need to en-hance public perception of (and demand for) vaccines, or to stimulate the political will required to commit funding and address implementation challenges – is predicated on rotavirus vaccines demonstrating a favorable balance of ben-efits to risks. Numbers – efficacy data, calculations of avert-able and attributable deaths, vaccine costs – are extremely useful tools, but determinations of a favorable balance (be-tween risk and benefit; between safety, efficacy and afford-ability) defy simple calculation. Where numbers fail, ethical Diarrheal disease caused by rotavirus claims approximately 500 000 lives each year, mostly in low-income coun-tries. Many of these deaths are prevent-able through the use of available rota-virus vaccines. Yet, in spite of a WHO recommendation that these vaccines be adopted into all national immuniza-tion programs, only a few countries have done so.