WHO reports success in distributing vaccines at ambient temperatures

Meningitis A vaccine MenAfriVac has already made its mark on world health, with its nontraditional development model and subsequent success in reducing disease making headlines. Now the World Health Organization (WHO) is trying to maximize its use by freeing the vaccine from the need to be constantly refrigerated during transport and storage.

WHO trialed the distribution model in collaboration with nonprofit and MenAfriVac codeveloper PATH. In a 10-day vaccination drive in Benin in 2012, the partners kept MenAfriVac outside of the cold chain for up to four days. Despite ambient temperatures topping 102°F, no vials were discarded on the grounds of excessive heat. Each vial featured a heat-sensitive sticker that alerted healthcare workers if the vaccine got too hot. Nine vials were discarded for passing the four-day limit.

Freed from the need to maintain a constant cold chain, WHO and PATH vaccinated more people per day. The pilot project vaccinated 155,000 people in 150 villages across a remote part of Benin. In the year following the vaccinations, there were no cases of meningitis A in the country. "The impressive coverage we saw in Benin ... paves the way for future campaigns in other regions with challenging geography, including countries where the vaccine will be administered later this year to rural populations living in the desert," director of the Meningitis Vaccine Project Dr. Marie-Pierre Préziosi said in a statement.

The WHO-PATH project, like many ambient-temperature vaccine initiatives, framed the benefits of its work in terms of the ability to transport vaccines to remote regions beyond the cold chain. Yet the potential gains facilitated by such vaccines extend beyond health. A related study by WHO recently looked at the economic benefits of transporting vaccines at ambient temperatures. WHO models suggest adoption of the approach taken in Benin could slash cold chain and logistics costs by 50%.

- here's the PATH release
- view the WHO study (PDF)