Every day during a vaccination campaign, a health care worker in rural Africa hops on a motorbike early in the morning. She rides maybe an hour and a half over dirt roads to the district capital, where the refrigerators are functional. She picks up a batch of meningitis vaccines and fresh ice packs, and heads back to the health center, where she can divvy up her cargo among teams that are heading out to local villages. Armed with heavy coolers, they make their way, often going miles on foot if they don’t have a motorbike or if the route would have them crossing log bridges or hiking up mountains. Only then, possibly hours down the road, can the three-person team set up shop and give the first of their 200 or more shots for the day.
Across the widest part of Africa runs a narrow band ominously nicknamed the meningitis belt. Here, meningitis A seasonally sweeps through villages. It is spread by a bacterium, and causes inflammation in the membranes that surround the brain. Even with treatment, it can result in brain damage. Children and adults are both susceptible. A typical case costs a family $90, according to a study done in Burkina Faso, where that amount represents three to four months’ income. It can push poor families even deeper into poverty, as they sell tools and livestock to pay for care for a sick baby.
That’s why the meningitis A vaccine is administered in massive campaigns. One in Chad ran for just ten days and immunized 1.8 million people, much of that through outreach like what I’ve described here. Adults and children over a year old can receive the vaccine, and it’s extremely effective. But the need to keep the vaccine vials cool is a major problem in getting the shot to everyone. The outreach team can only travel so far in a day—about four to five hours—because they’ll have to pack up and return to the center to pick up fresh ice and vaccines the next morning.
Many of Africa’s health centers have refrigerators and ready access to electricity or kerosene to run them, but others (2 out of 14 in the Banikoara district in Benin, for example) do not. This week, the World Health Organization published a bulletin describing just how much time and effort it takes to maintain the “cold chain.” That’s the continuous refrigerated environment a vial of vaccine inhabits from its manufacture in India, through international shipping, to the health centers and its final ride in a cooler to the moment it’s injected into somebody’s arm. The cold chain is, the report concludes, an enormous drain of resources.
Happily, the report has a counterpart, published this week in Vaccine: a success story from a meningitis campaign in Benin where workers had permission to keep the vials out of the cold chain for up to four days at a time. “Many vaccines today have some stability we’re not taking advantage of,” says Simona Zipursky, a program coordinator at the World Health Organization, which worked with a nonprofit called PATH on this project. They didn’t reformulate the vaccine, which normally comes with a label stating it should be kept at 2-8 degrees C (about 36-46 degrees F). Instead, they consulted documents from the vaccine’s development that showed it could stay stable, with no change in its chemistry (and presumably no change in safety or effectiveness) if it was kept at warmer temperatures. Since the vaccine is manufactured in India, they approached Indian regulators with this information, and were able to get a new label stating that the vaccine could be used in a “controlled temperature” chain, where it could stay out of the fridge for four days, so long as the temperature never exceeded 40 degrees C (about 104 F).
The new label made a huge difference. Centers didn’t have to freeze dozens of ice packs every morning, so they could get started earlier. And outreach teams targeting distant villages didn’t have to return home each night, but could keep vaccinating and move to another, more remote village in the morning. Over the course of the four days they could make a loop through the countryside and vaccinate people they never could have reached under the cold chain system.
Health care workers spend a lot of time on logistics, Zipursky says. Supervisors can’t supervise while they’re running back and forth delivering ice packs. The same worker who provides vaccinations and keeps an eye on their temperature (and who, studies show, spends 20% of her time on “cold chain logistics”) is taking time out from prenatal checkups or dispensing malaria medication to do it. Get rid of the cold chain, the WHO calculated, and campaigns could reach more people with vaccines costing half as much.
After the controlled-temperature experiment, the health care centers in Benin returned to business as usual: in this case, a polio vaccine campaign with the regular cold chain. Despite concerns that workers might get confused and think all vaccines could be left out in the heat, the polio campaign went without a hitch. Follow-ups on the meningitis campaign showed that nobody who got the controlled-temperature vaccine contracted meningitis that season, indicating that the vaccine maintained its efficacy as promised. Over 15,000 vaccines were given, and only a handful had to be discarded for surpassing the four-day limit.
The next step is to pursue the controlled temperature chain strategy for yet more vaccines. They might try HPV next, says Zipursky, because it’s another vaccine adminstered by traveling teams. Regulatory hurdles must be cleared individually for each vaccine, but the benefits of the controlled temperature approach are hard to ignore: when asked if they’d like to do their next campaign this way, 98.7% of supervisors and 100% of vaccinators said yes.