Stockpiling for the future

Members of the International Coordinating Group on Vaccine Provision — UNICEF, MSF, IFRC, and WHO — work in concert with vaccine manufacturers to provide emergency vaccines during epidemics. The ICG manages a vaccine stockpile funded by Gavi that has been capped at 6 million doses since 2004, an amount thought to be sufficient to match demand at all times. Gavi-funded countries can request free doses during outbreaks.

The stockpile had been sufficient in controlling outbreaks in a one-year period up until 2016, when there were two connected outbreaks in Luanda, Angola, and in Kinshasa, Congo, whose populations far outnumbered the amount of available vaccines.

Sanofi Pasteur’s response to yellow fever in Angola in 2016

Source: WHO, Sanofi Pasteur

From February until August 2016, Sanofi Pasteur shipped a total of 11,825,500 yellow fever vaccine doses to Angola.
In addition, 4,030,000 doses were shipped to Democratic Republic of Congo for emergency response.

WHO took the exceptional decision to fraction available vaccines into multiple lower doses so as to immunize a greater number of people, with a 10-dose vial used to vaccinate up to 50 people. This was enough to tackle the outbreak and reduce the spread of the disease, but not to ensure lifelong immunization, as a full dose would.

Another outbreak emerged in Brazil later that year, when cases were reported in parts of the country where people were not routinely immunized since they were outside the endemic areas. The country was able to contain the epidemic by improving its vaccine production — Brazil is one of six nations that manufacture the yellow fever vaccine — and requesting additional doses from the ICG. More cases were then reported in 2017, prompting the country to start a new immunization campaign.

The events of 2016 sparked questions about the sustainability of the vaccine’s supply chain. Prior to this, Gavi estimated that routine immunization campaigns would increase around the world, leading to better coverage and a decrease in the stockpile over the next few years. But these recent events showed that the ICG needed the stockpile more than ever.

Instead of increasing the stockpile, which could result in losing expired doses in the absence of an outbreak, the ICG opted to implement a revolving stockpile. This means that 6 million doses are available at all times, rather than the stockpile depleting during outbreaks. Manufacturers must now be ready to ship new doses within 72 hours and to immediately replace doses from the stockpile that are sent out to respond to emergency situations. So, there is a reserve of yellow fever vaccine doses available at all times for potential outbreaks in the future.

Vaccination drive yellow fever in Togo (Africa) in 2007
Copyright: Sanofi Pasteur - Norbert Domy

“We still want to be able to ensure that we'll have a vaccine available if and when needed, and an opportunity to replace it as quickly as possible. But those opportunities are greater realized when you have a routine immunization program in place,” said Heather Deehan, chief of the vaccine center at UNICEF.