By Andrea Stanglmair
For decades, distribution of vaccines in Africa and other warm regions have been hampered by the need to keep vaccines refrigerated. An immunization campaign in Benin has shown that vaccines can be delivered to remote areas without using ice boxes, and yet still remain viable. The challenges of keeping vaccines cool appear at every step of the production chain from manufacture to use. Most vaccines must be kept cold, at temperatures between 2 and 8 degrees Celsius – a major challenge in remote areas without electric power. But the World Health Organization says a new vaccine aimed at preventing Meningitis A can be stored for up to four days at up to 40 degrees Celsius, without any loss of potency, efficacy or safety. This could really change the way mass vaccination campaigns are conducted in remote or low-resources settings.
Vaccination Campaign in West Africa
Conducted as part of a meningitis A vaccination campaign in Benin in 2012, a recently published study in the journal Vaccine represents a breakthrough not only for the vaccine MenAfriVac, but potentially for increasing the efficiency, coverage, and affordability of other lifesaving vaccines as well. Especially in remote, hard-to-reach areas where keeping the vaccine cold is difficult. MenAfriVac was first introduced in 2011 in a mass vaccination campaign in Africa’s meningitis belt. However it was not until the Benin trial that the vaccine was administered outside of the cold chain. The Benin study aimed to assess and demonstrate for the first time the feasibility and acceptability of using the Controlled Temperature Chain (CTC) approach in a massive vaccination campaign, rather than keeping the vaccine within the traditional recommended 2°to 8°C temperature range at all times.
Findings from the study show that the new flexibility makes it easier for vaccinators to reach ‘the last mile’ – the time from when the vaccine leaves the refrigerator at the district health center until it is injected. Vast resources are spent on the cold chain system, such as acquiring and transporting freezers, ice packs, transportation fuel, electricity fuel, ect. Sometimes, it is not only costly, but it is also very challenging to reach remote areas with such constraints. Additional transportation and human resources costs are also incurred when vaccines, cold boxes, and fresh ice packs need to be replenished. Not having to worry about freezer packs nor having to return to the district health center each day to replenish vaccine supplies means that health staff could vaccinate more people in a shorter amount of time and reach more remote areas. The potential gains by such vaccines extend beyond health. Removing the refrigeration requirement could also reduce costs. A related study by WHO looked at the economic benefits of transporting vaccines at ambient temperatures. Working outside the cold chain for a limited time could cut storage and transportation costs in half. As a result of the cold chain requirement, there is normally a lot of wasted vaccine vials during immunization campaigns. Normal wastage during vaccination campaigns can be as high as 5 percent, because as soon as the 2 to 8 degree temperature range is exceeded, the vaccine must be discarded.
Hopes for the Future
“In many countries where the cold chain is critical and can be a challenge, this new innovative approach could be a game changer,” says Stefano Malvolti, director of vaccine implementation at the GAVI Alliance, a public–private health partnership based in Geneva. The next step will be for pharmaceutical developers to see if the refrigeration requirements for other vaccines, such as yellow fever and cholera, can also be changed and being approved for CTCs. Many vaccines are actually thermostable outside the recommended temperature range, and some newer ones in particular can often remain viable for days, weeks or even months after exposure to higher temperatures. CTC would allow vaccines to be stored for short periods at higher temperatures for the ‘last mile’ of distribution, especially helpful in hot developing countries where electricity and refrigeration is lacking. If widely used, the approach could significantly reduce the cost and logistical challenges of reaching people living in remote areas and remove a major constraint to achieving universal coverage with vaccines.