From fragile to final gains: vaccines to end polio for good

June 15, 2018 by PATH

In 2017, 74 cases of type 2 poliovirus were reported in Syria before a swift and massive immunization response was deployed to stop the circulating virus in its tracks.

A nurse prepares doses of oral polio vaccine (OPV).

A health worker readies doses of oral polio vaccine (OPV). Photo: PATH/Gabe Bienczycki.

The outbreak, though apparently contained, illustrates how low vaccination rates in Syria and other conflict-ridden regions are a threat to eradication efforts, opening a window for polio strains to creep back into circulation and underscoring the critical importance of continued robust vaccine coverage in vulnerable regions.

Vaccines have brought us to the cusp of polio eradication, having reduced the number of cases by more than 99.9 percent since 1988—the year the international health community came together to form the Global Polio Eradication Initiative. But vaccines can only keep outbreaks at bay when they are widely used.

Even after the last case of polio is detected, strains can still lurk in the environment, and vaccination will be necessary for decades to come until we’re certain the virus is no longer a danger. That’s why at PATH, our eyes are on the horizon to anticipate global vaccine needs in the polio eradication and post-eradication eras. We’re working to shore up an affordable global vaccine supply by providing technical and clinical expertise to polio vaccine manufacturers as they work toward securing World Health Organization approvals; exploring ways to boost the performance of current polio vaccines; and developing new vaccines to maintain an emergency stockpile in case of an outbreak post-eradication.

“At PATH, our eyes are on the horizon to anticipate global vaccine needs in the polio eradication and post-eradication eras.”

These new polio vaccine candidates – novel oral polio vaccines (nOPVs) – are in early stage development and, if successful, could be deployed to quickly contain an outbreak. Currently available OPVs have had an invaluable impact in driving down polio cases, and they remain the best tool for containing outbreaks because they halt wild polio transmission. But the current OPV can, in very rare cases, revert to its virulent form and become a risk in the community, such as the 2017 outbreak in Syria. In the post-eradication era, we must reduce the risk of future outbreaks associated with live vaccine and are optimistic that nOPV will be a safer alternative.

Today, only a very tiny handful of parents have to endure the frightening, sometimes life-altering, effects of a child’s polio diagnosis. With a multipronged approach to solidify our foothold against the last lurking pockets of poliovirus, along with a political commitment to invest in vaccine for several decades to come, we have every reason to believe that we will relegate polio to the history books.

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