A vaccine capable of enduring scorching temperatures for months at a time could strike a decisive blow in the fight against rotavirus, preventing nearly half a million children around the world from dying of diarrhoea each year.
Médecins Sans Frontières (MSF) has hailed successful trials of the BRV-PV vaccine in Niger as a “game changer” in tackling rotavirus infection, which is the leading cause of severe diarrhoea globally and claims the lives of an estimated 1,300 children daily, most of them in sub-Saharan Africa.
According to results published in the New England Journal of Medicine, the vaccine has proven as effective as those currently used to treat severe gastroenteritis. Trials in Niger’s Maradi region successfully treated 4,000 children under the age of two.
Unlike existing vaccines, the BRV-PV vaccine does not require refrigeration and can remain stable for up to one year at 37C or six months at 40C. It is particularly effective against the strains of rotavirus found in sub-Saharan Africa, as well as affordable: at only $2.50 (£2), the vaccine could potentially be rolled out quickly in routine immunisation programmes.
“This is a game-changer,” said Dr Micaela Serafini, MSF’s medical director. “We believe that the new vaccine can bring protection against rotavirus to the children who need it most.”
Diarrhoea is the second largest cause of death in infants and children worldwide, primarily in low-income countries where access to clean water and sanitation is limited. Rotavirus is highly contagious, particularly among babies and young children, and can be spread by contaminated hands, objects such as toys and surfaces, and water and food.
Children in the world’s poorest countries account for 82% of rotavirus deaths, but vaccines make a significant difference. In Mexico, diarrhoeal deaths among children under five declined by as much as 50% after rotavirus vaccines were introduced.
A nurse administers a rotavirus vaccine to a baby in Port-au-Prince, the Haitian capital, as part of a 2014 public health initiative. Photograph: Hector Retamal/AFP/Getty Images
The World Health Organization recommends that rotavirus vaccines should be included in all national immunisation programmes, and considered a priority in south and south-east Asia and sub-Saharan Africa. The BRV-PV vaccine is awaiting pre-qualification from the WHO before it can be rolled out.
Licensing the product could take up to 18 months, said Anna-Lea Kahn, a WHO technical officer looking at innovations for facilitating vaccine supply and delivery. During that period, WHO scientists evaluate data supporting the vaccine’s quality and safety, drawing on independent specialist help when needed.
Most difficulties with vaccine delivery tend to arise during the “last mile” of the vaccine supply chain, said Kahn. “That’s where it goes wrong the most: where being able to maintain the cold chain is hardest; where constraints are most pronounced, be it due to lack of electricity or lack of resources, or inability to maintain a cold fridge. There may be geographical barriers, too, presenting a logistical challenge.
“In these scenarios, not having to depend on the cold chain … can make a valuable difference in getting vaccines to those who otherwise might not receive it.”