The paediatric rotavirus vaccination programme that is currently being rolled out by the WHO worldwide may actually be more cost-effective than previously thought, as vaccinating children against rotavirus may indirectly protect unvaccinated adults from the highly contagious disease.
Rotavirus is the most common cause of severe diarrhoea in infants worldwide, accounting for over a third of severe diarrhoea cases worldwide. In 2008, an estimated 453,000 children under the age of 5 died as a result of the virus, so rotavirus diarrhoea represents a major cause of childhood morbidity and mortality worldwide. Fortunately, the vaccines that are available for rotavirus have been shown to be effective, with Rotarix (GlaxoSmithKline) and RotaTeq (Merck & Co) showing high efficacy against severe rotavirus diarrhoea in industrialized countries.
In 2009, the WHO recommended that the use of rotavirus vaccines should be rolled out across all countries on the basis that they would prevent a large amount of severe disease and deaths, particularly in Africa and Asia where mortality from rotavirus was high. Since then, eight GAVI-eligible countries – that is, countries with a Gross National Income per capita below US$1520 – have been approved funding for the rotavirus vaccine. The countries are Sudan (2011), Armenia (2012), Ghana (2012), Rwanda (2012), Malawi (2012), Moldova (2012), Tanzania (2012) and Yemen (2012), following in the footsteps of Nicaragua (2006), Bolivia (2008), Honduras (2009) and Guyana (2010). The GAVI Alliance and its partners plan to introduce the vaccine to at least 40 of the world's poorest countries by 2015. If used in all GAVI-eligible countries, rotavirus vaccines could prevent about 180,000 deaths per year.
The research carried out at Northwestern Memorial and Children's Memorial Hospitals in Chicago, and published in Clinical Infectious Diseases, compared the prevalence of rotavirus in stool samples collected from 3,500 adults before and after the implementation of paediatric rotavirus vaccination in the US. The results showed that the number of unvaccinated adults testing positive for rotavirus had almost halved in 2010, following the implementation of the widespread vaccination schedule, compared to previous levels in 2006.
It would seem that the most likely reason for this decline in rotavirus in unvaccinated adults is that vaccinating children decreases the amount of rotavirus circulating in the community. The fact that the rotavirus immunisation schedule has been so successful in children, coupled with the indirect protection of adults, really highlights the value of the worldwide rotavirus vaccination programme.
Do you think the successes currently being seen with the rotavirus vaccination programme are sustainable?
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If you'd like to hear more about strategy and innovation in vaccines, including a talk on âRotavirus vaccines: successes, challenges and opportunites', you might be interested in attending the World Vaccine Congress & Expo 2013, 16-18 April 2013 at the Gaylord National Hotel and Convention Center, Washington DC.