Vaccine Development Global Program


Vaccines for finishing the fight

Indian mother and child wearing purple head scarves.

Photo: PATH/Julie Jacobson.

The world has made remarkable progress against polio and is very close to eradicating this disease, having reduced the number of cases by more than 99 percent since 1988, when the global health community came together to form the Global Polio Eradication Initiative. Reaching this milestone will mark only the second time in history that an infectious disease has been fully eradicated, after smallpox was eliminated in 1979.

Completing the job will require stopping transmission of polio and maintaining immunity for several years thereafter, and new tools are needed to meet these challenges. PATH is providing technical support on the development of high-quality and low-cost polio vaccines needed to help achieve eradication and maintain protection posteradication.

Poliomyelitis (polio) is a highly infectious disease caused by a virus that invades the nervous system and can cause permanent paralysis. While polio can strike at any age, it mainly affects children under age five. Because there is no cure, prevention through vaccination is the only protection for children.

There are two types of vaccines against polio—oral polio vaccine (OPV) and inactivated polio vaccine (IPV) that is delivered via injection. While OPV has been a powerful tool in the campaign against polio and is extremely inexpensive (US$0.14 to $0.17 per dose), it has two drawbacks: the weakened virus in OPV can mutate into vaccine-derived poliovirus (VDVP) that can circulate and cause polio infections in a community and, on rare occasions, OPV can result in vaccine-associated paralytic polio. The currently available IPVs are safe and effective, but at more than $3 per dose, they are out of reach for low- and middle-income countries.

PATH is working with partners on the following new vaccine tools that can help the global community complete eradication and ensure protection post-eradication.

Lower cost OPV

OPV is still needed for maintaining population immunity, stamping out pockets of endemic wild-poliovirus transmission, and controlling outbreaks. Because billions of doses of OPV are delivered every year, even a modest cost reduction could help make better use of constrained public-health resources.

Much more affordable IPV

Because vaccination will be needed for years and even decades after polio transmission is ended and because VDPVs will continue to occur until all countries switch to IPV, it is essential to bring the price of IPV vaccines down so that low- and middle-income countries can afford them. Strategies to reduce IPV costs could include adjuvants—additional ingredients that can boost the body’s immune response—or needle-free delivery methods that require smaller amounts of vaccine for each dose.

Affordable IPV-containing pediatric combination vaccines

Ultimately, it would be advantageous to include more affordable IPV into combination vaccines that are part of the basic childhood immunizations to protect future birth cohorts in low-income countries.

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