The Triumph of Polio Eradication, and the Risks to This Monumental Achievement

Just two generations ago, polio paralyzed or killed more than half a
million people around the world each year. Parents in the United
States kept their children indoors during “polio summers,” but the
disease still took a fearsome toll, killing thousands and disabling
tens of thousands more.

What a difference a vaccine makes. Thanks to Jonas Salk—and many other
dedicated researchers and clinicians—polio has been eradicated in the
United States. And worldwide, we’ve made immense progress: a global
vaccination drive has saved 5 million people from paralysis, and
targeted investments and effective partnerships have brought us to the
cusp of eliminating this devastating disease. In 2016, just 42 cases
were reported. But today, the public health community is neglecting threats that
could lead to polio’s resurgence. As an expert on supply risks, I see
major red flags in the polio vaccine supply chain.

Eradicating polio requires a steady and reliable supply of quality
vaccines. Unfortunately, global health organizations like UNICEF often
base their predictions on the theoretical supply that providers are
capable of producing, rather than the actual supply they deliver. This
isn’t just an academic quibble. In general, manufacturing and
distribution challenges sometimes disrupt supply chains and cause
major product shortages. The specific complexities associated with the
global vaccine supply chain compound on these general risks and have
historically led to chronic shortages for a variety of essential
vaccines.

It gets worse: right now, it is an open secret among the global health
community that even the theoretical supply of polio vaccines is
insufficient to immunize the world’s children. The world is switching
from traditional oral (OPV) to injectable (IPV) vaccines. UNICEF
reports that even in the ramp-up period from 2014 to 2018,
manufacturers were only able to supply 46 percent of the contracted
IPV quantity of some 85 million doses per year, as manufacturers
experienced major delays in scaling up their theoretical capacity. As
it stands, at least 400 million doses will be needed while our current
theoretical capacity is at least 25 percent short, even in the absence
of anticipated plant closures. Simply put, our supply chain for polio
vaccines can’t deliver the doses we need, even in best-case scenarios.

But rather than taking urgent steps to boost the supply of vaccines by
making long-term purchase and investment commitments at sufficiently
attractive prices, the polio community is cutting corners.

In the United States, the American Academy of Pediatrics recommends
that children receive at least four doses of polio vaccine. The global
polio eradication campaign had targeted two doses in low-income
countries, ironically where the risk of new outbreaks is largest. Now,
faced with the supply problems, polio campaigns are only targeting to
vaccinate children with a single dose, praying this will provide
sufficient immunity.

The polio community is also failing to prepare for a scenario in which
the already-insufficient theoretical capacity to produce needed
vaccines is curtailed even further. To appreciate this risk, the
community need not look too far: between 2011 and 2017, two of the
major suppliers of the established oral vaccine were shut down for
more than four consecutive years because of quality concerns,
contributing to global shortages in this traditional product line as
well.

Yellow Fever is an acute viral disease which causes between 84,000
to174,000 severe infections and up to 60,000 deaths annually. More
than 900 million people are considered at risk. There are only four
vaccine suppliers qualified by the World Health Organization. In 2014,
two were completely shut down for several years, and a third faced a
major shortage of a critical input. As a result, fewer than half of
the required doses of yellow fever vaccine could be supplied in 2014.
Even with all four suppliers operating at full capacity in 2017, there
was still a 10 percent shortage in vaccine supply that year.

Experience from other sectors also shows that the polio community must
take urgent steps to mitigate these risks. Consider a now-famous case
from the mobile phone industry. In March 2000, a lightning-induced
fire at a Philips manufacturing facility in New Mexico damaged
millions of mobile phone chips. Two of Philips’ customers – Nokia and
Ericsson – responded in dramatically different ways. Nokia called on
other suppliers to fill orders and redesigned its phones to
accommodate chips from new sources, while Ericsson passively accepted
Philips’s word that the plant would soon resume operations. The
result? Nokia took over Ericsson’s market share, and Ericsson was
forced out of the mobile phone industry entirely.

Lightning doesn’t strike every day, but it does strike. When it comes
to polio eradication, we can’t afford to take these risks. We must be
prepared for when vaccine plants shut down.

After an outbreak of vaccine-derived polio last summer in the
Democratic Republic of the Congo, we learned that the virus had gone
undetected for two full years—and then watched as it leapt across the
country and threatened to cross international borders. The worldwide
switch from oral to injectable vaccine is in part based on the risks
posed by vaccine-derived polio. The Congo experience is a wakeup call
that time is of the essence in providing the world with sufficient
capacity to produce injectable polio vaccines.

As global health organizations acknowledge World Polio Day, we find
ourselves within striking distance of eliminating a long-standing
scourge. That’s worth celebrating, of course. But it’s also time for
polio campaigners to acknowledge what they privately know—that we
simply don't have the vaccine supplies in place to guarantee
prevention of an epidemic recurrence. They must recognize the urgent
risks that could undo years of progress, and take steps to ensure the
ongoing supply of polio vaccines.