Discovery that one vaccine can withstand heat means it can be taken to more remote areas at less cost, opening the way for more comprehensive vaccination campaigns if other vaccines react the same way
DAKAR (Thomson Reuters Foundation) – Research has shown that a meningitis A vaccine can survive high temperatures for up to four days, and could therefore reach more people in remote areas across the African continent and cost half as much as it does now, a paper in the scientific journal Vaccine reported on Wednesday.
Scientists writing in the journal reported that MenAfriVac, used for protecting adults and children against meningitis A, could withstand temperatures of up to 40°C for as long as four days without losing its efficacy, according to trials in Benin in 2012.
This means the vaccine could be taken to distant health posts without the need of a cold chain – freezers, refrigerators and cool boxes for keeping the vaccine between 2°C-8°C – a fundamental requirement of the World Health Organisation (WHO).
“The need to continually keep vaccines in a 2–8◦C cold chain is a major constraining factor for achieving universal immunization coverage, especially in the ‘last mile’, from health centre to vaccinee,” the paper said. “The logistical challenges in maintaining the cold chain, from faltering electricity, poorly functioning or absent equipment, to ice pack production capacity are significant.”
The paper’s lead author, Simona Zipursky, said the discovery could open the way for other vaccines also to be used outside the cold chain. “We’re also looking at other vaccines that are used to control mass outbreaks, like the cholera, yellow fever and measles vaccines, to see if they too can be used outside the cold chain,” she said, adding that further research was needed to test their stability.
Meningitis outbreaks occur throughout the African meningitis belt, a region stretching from Senegal to Ethiopia, every eight to 12 years. In 1996 and 1997, an epidemic killed more than 25,000 people and made 250,000 ill. Those who survive often suffer from deafness, epilepsy, limb loss and/or mental retardation.
Periodic vaccination campaigns target up to 70 percent of the population, all those aged 29 and under, but the need to keep the vaccines cool as well as the labour intensive nature of the work mean that costs quickly mount.
“As a result of removing the cold chain, the cost of a vaccination has come down from $0.24 per person to $0.12 per person,” Patrick Lydon of the WHO told Thomson Reuters Foundation by telephone from Geneva. The money saved could be used to invest in other healthcare essentials.
Lydon said that despite this, vaccine manufacturers had been scared to go against the grain and to label vaccines as suitable outside the cold chain, a regulation that has been in place since the start of the WHO vaccination programme 40 years ago.
The research conducted for the first time in Benin has profound implications for vaccination campaigns around the world, Zipursky said.
“What the economics doesn’t take into account is the opportunity costs. At the moment, it’s health workers that have to make sure the cold chain is working - time they can spend immunising children, treating malaria or providing ante-natal care,” she said.
Although immunization is cost effective, over 20 million children worldwide do not receive vaccinations they need, partly because of the cold chain, and remain at risk of vaccine-preventable diseases each year, the paper said.
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