One of the reasons that millions of people worldwide are undervaccinated and susceptible to vaccine-preventable diseases is the need to keep vaccines refrigerated—something that is difficult to do in warm and hard-to-reach areas of the world.
But a 10-day pilot project to deliver meningitis A vaccine to a remote area of Benin in western Africa found it is possible to deliver efficacious vaccine without the need to maintain refrigeration. The project’s description and results were published online this week in Vaccine.
MenAfriVac is a meningitis A polysaccharide conjugate vaccine intended for use across the sub-Saharan African “meningitis belt,” countries in which the incidence of the infection is high. As with most vaccines, MenAfriVac was supposed to be kept at a temperature between 2°C and 8°C (36°F and 46°F). In October 2012, based on scientific studies and analyses submitted by the vaccine manufacturer (Serum Institute of India), MenAfriVac’s regulatory agency of record (India) and the World Health Organization (WHO) both approved a temperature control revision that said the vaccine could be stored at temperatures up to 40°C (104°F) for not more than 4 days immediately prior to administration.
Vaccine vials were transported in coolers without ice. To ensure that the vaccine did not exceed the 40°C threshold, the project coordinators placed inside each cooler a card inside that changes color immediately upon being exposed to 40°C. They also affixed to the vaccine label a vaccine vial monitor, a heat-sensitive sticker that changes color to reflect cumulative exposure to heat.
Armed with those safeguards, vaccination teams, each comprising a nurse and 2 volunteers, set off for 150 villages and hamlets in Banikoara, a rural area in northern Benin, with the goal of vaccinating an estimated 147 000 children and adults up to age 30 years. Ultimately, the vaccination teams immunized 155 596 children and adults, with each team vaccinating on average 318 individuals a day. Only 9 of about 15 000 vaccine vials were discarded for surpassing the 4-day limit, and no vial was discarded because it was exposed to a temperature of 40°C or higher or because a vaccine vial monitor had reached its end point.
“Finding solutions to reducing the cost and logistical challenges of reaching people living in remote areas would remove a major constraint to achieving universal coverage with vaccines beyond MenAfriVac. Indeed, a similar approach is being explored with the manufacturers of other vaccines, such as the yellow fever or the oral cholera vaccines,” commented Michel Zaffran, coordinator of WHO’s Expanded Program on Immunization and former director of Optimize, a WHOand PATH collaboration aimed at improving immunization systems and technologies, in a release.
Support for the operational costs of the campaign was provided by the Global Alliance for Vaccine and Immunization. Optimize, funded by the Bill & Melinda Gates Foundation, provided additional specific funds for training, supervision, and the evaluation of the project.