Outdated supply and distribution systems are delaying and limiting the impact of vaccines on safeguarding millions of Africans, according to researchers.
A special issue of Vaccine journal, titled Building Next Generation Immunization Supply Chains, said that vaccine stock-outs – or complete unavailability – occurred at least monthly for one in three countries, while 19% to 38% of vaccines were not refrigerated properly.
In a literature review of 45 studies that assess temperature of vaccines, UNICEF found that 33.3% of storage units in wealthier countries and 37.1% in lower-income countries contained vaccines that had been exposed to temperatures below the recommended ranges.
Benjamin Schreiber, a UNICEF senior health adviser and one of the editors of the articles, said the outmoded delivery systems could compromise the potency of vaccines.
“Often a supply arrives in a capital city and has to travel hundreds of miles before it gets to the correct clinic or health centre,” he said.
“We know a vaccine has to be kept stable at 2C to 8C, but our data shows that’s not happening at least 20% of the time.”
The 29-article issue was coordinated by the global health not-for-profit group PATH, with guest editors from the Bill & Melinda Gates Foundation, UNICEF, and the Johns Hopkins Bloomberg School of Public Health, to identify challenges and supply solutions to modernise immunisation supply chains.
The problem was most pronounced in sub-Saharan Africa, where 38% of countries reported national-level stock-outs annually.
The DTP (diphtheria, pertussis and tetanus) vaccine accounted for 43% of the stock-outs, and the BCG (Bacillus Calmette-Guerin) tuberculosis vaccine accounted for 31%.
Dr Jean-Marie Okwo-Bele, director of the World Health Organisation (WHO) Department of Immunisation, Vaccines and Biologicals, said government funding delays accounted for 39% of stock-outs, while 23% were caused by delays in procurement, and about 18% were because of poor forecasting.
“For too many countries, it is nearly impossible to collect and harness data to forecast vaccine requirements and deliver vaccines when and where they are needed,” he said.
“But there are innovations such as electronic data systems that are being piloted and scaled up in developing countries that could and should be more widely adopted.”
Immunisation supply chains were first developed in the late 1970s. By 2010 they were storing and transporting four times the volume of vaccines, according to the WHO.
Dr Orin Levine, director of vaccine delivery at the Bill & Melinda Gates Foundation, said only a handful of countries had considered how supply chains could be used to improve immunisation coverage.
“Immunisation is one our biggest public health success stories, but safe, effective vaccines don’t deliver themselves,” he said.
“With consistent, visible support from national and local leaders, every community can have 21st-century systems that reliably deliver faster lifesaving vaccines to everyone who needs them.”
Vaccines prevent an estimated 2-3m deaths every year, but an additional 1.5m could be avoided if global immunisation coverage improved, according to the WHO.
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