Dr Sanet Aspinall reports on the progress of the Rotavirus Vaccine trial to World Health Organisation (WHO)

The World Health Organisation's Committee on Vaccines for Diarrhoeal Diseases, invited Dr Sanet Aspinall to their meeting, heald on 23-24 April 2007 to provide an update on the Phase III Rotavirus Vaccine efficacy trial currently conducted in South Africa and Malawi.

Dr Aspinall, the Managing Director of Clinical Research Centres SA, now known as Synexus Clinical Research SA, part of the Synexus group of companies, is also the National Coordinator of this vaccine trial in South Africa.  Several Synexus Clinical Research SA sites are currently participating in this study.  In South Africa alone, 3167 subjects have been enrolled in the trial and are being followed for diarrhoeal episodes.

The Rotavirus Vaccine Project, a partnership between the WHO and the Seattle-based non-profit organisation, PATH, and the vaccine's manufacturer, GlaxoSmithKline, is currently involved in efficacy studies with various sites in South Africa and Malawi.

The aim of this current study is to evaluate the efficacy of the vaccine in the developing world and to assist with WHO pre-qualification of the Rotavirus vaccine for use in Africa.  The vaccine is particularly important to Africa.

In sub-Saharan Africa, diarrhoeal diseases follow malaria and pneumonia as one of the most common causes of mortality in children under 5 years.  However, a recent report has highlighted that while the global mortality rate due to diarrhoeal diseases has declined, the overall incidence of diarrhoeal disease in the under 5 age group, has not.  On average, 3.2 eposides of diarrhoea per child-year are still seen resulting in an estimated 4.9 deaths per 1000 children annually, constituting approximately 20% of childhood mortality.

Rotavirus is the single most important aetiological agent of diarrhoea, responsible for 20-25% of all deaths due to diarrhoea and 6% of all deaths among children less than 5 years old.  Rotavirus infections are characterized by the acute onset of watery diarrhoea, fever and vomiting and are more likely to be associated with dehydration and hospitalization.  Effective medical care results in only 20-40 children dying per year due to rotavirus diarrhoea in the United States.  However, estimates from Africa attribute 301-411 deaths per day or a total of 10,000-15,000 deaths in children under 5 annually to Rotavirus infection.

Improvements in sanitation and the availability of clean water have not decreased the rate of Rotavirus diarrhoea in developed countries, focusing the need to develop vaccines as the first strategy of prevention.

RotaRix was licensed in South Africa in July 2006 and is administered orally on a two dose schedule to children less than six months of age in the private sector.  It is not yet available to the public.

Several challenges still remain, including efficacy of the vaccine against the specific human rotavirus serotypes remain to be addressed and this study is extremely important to the scientific community to provide these answers.