South Africa's introduction of a rotavirus vaccine will be launched at the earliest on 1 August 2009, after a three-month delay in its registration by the Medicines Control Council (MCC).
About four-fifths of rotavirus infections occur in Africa and Asia; it is the leading cause of severe, dehydrating diarrhoea in children younger than five years, and is blamed for the deaths of between 140,000 and 150,000 children annually in Africa and 500,000 globally.
In the developing world, diarrhoeal diseases account for 20 percent to 25 percent of deaths among children aged under five years. According to a 2005 World Health Organization report on rotavirus vaccine research, infection occurs in 25 percent to 40 percent of children hospitalized with diarrhoeal illness in Africa.
Nicola Page, a senior medical scientist at South Africa's National Institute for Communicable Diseases, told IRIN the transmission route was faecal-oral; the virus - part of the Reoviridae family - and its "three protein layers make it able to survive on a multiple of surfaces."
Most of the world's children - 95 percent - will have suffered a rotavirus infection by the time they are between three and five years old, but in Africa this has usually happened by the time a child reaches the age of two.
Peak incidence occurs in children aged between 6 months and 18 months, and the younger the child the higher the risk posed by the rotavirus. Page said children were usually infected numerous times, but the first infection was almost always the most severe, becoming milder with each subsequent bout.
The vaccine was designed to protect against the first infection, and would also alleviate the burden of hospitalization in already stretched health infrastructure.
During the incubation period of less than 48 hours the virus begins attacking the villi - tiny tongue-shaped projections on the wall of the small intestine - causing vomiting, watery diarrhoea and fever that can lead to rapid dehydration.
Infections of the highly contagious rotavirus occur seasonally in South Africa, usually during the winter months from late March to August.
Page said the two-dose vaccine, part of South Africa's expanded programme of immunization, had been undergoing local trials since 2002. It will be given to babies when they are six weeks old, and again at 14 weeks.
Reasons for delay
Professor Anthony Mbewu, president of South Africa's Medical Research Council, said the rotavirus immunization programme would save thousands of lives each year.
|[The] biggest challenge to immunization is not the vaccine, but getting children vaccinated|
"[The] biggest challenge to immunization is not the vaccine, but getting children vaccinated," and overcoming such challenges as logistics and healthcare, he told IRIN.
South Africa's health department failed to respond to questions by IRIN, but according to reports the company awarded the tender to supply the vaccine had discontinued manufacture of the powder form registered by the MCC, and was only available as a liquid, which had not been registered.
The vaccine had to be re-registered by the MCC, which took place in March, allowing for batches to be sent to the National Vaccine Quality Control Laboratory for testing. Health department spokesman Fidel Hadebe has reportedly said the soonest possible introduction of the vaccine would be 1 August.