A spectacular polio outbreak—over 100 cases in Somalia—is obscuring progress in eradicating the disease. It’s not the first time. 2010 saw an even larger outbreak, 460 cases in Tajikistan. Yet the next year, cases went to zero in India which once led the world in polio.
Today the good news is that the type three strain of polio might be gone forever, joining type two in oblivion and leaving only type one to reckon with. There have been no type three cases detected in the world since last November. However, because type three polio is less paralytic than type one, it is harder to detect. But surveillance is bulked up in places where type three has appeared previously. And, encouragingly, sewage samples have been negative suggesting an absence of asymptomatic circulation. Type two polio was driven to extinction in 1999, the last case appearing in India. The disappearance of type three would represent “another proof-of-principle, like the eradication of [type two],” according to WHO spokesperson Sona Bari. The virus is under pressure. “If [type three] can be interrupted, it gives us more evidence that [type one] eradication is not far behind.” Bari emphasizes, however, that “we are still holding our breath” to see if type three is really gone.
The Somali outbreak has little impact on the main eradication fronts: Nigeria, Pakistan and Afghanistan. Afghanistan has pushed cases down to just four this year, historic lows reached not with the help of chance as in the past but improvement in the quality of immunization campaigns, according to Apoorva Mallya, program officer at the Bill & Melinda Gates Foundation. The number of children never receiving vaccine is down. Because more children are being vaccinated, population immunity is up.
The gains in Afghanistan come against a backdrop of insecurity not unlike that in Somalia. Somalia suffered an outbreak of over 100 cases in 2005 but was polio free again by the end of 2007. The country has since served as the exemplar for smashing the virus despite instability.
The eradication program doesn’t take the Somali outbreak lightly, but it is “nothing to detract from the 2018 timeline,” said Mallya of the plan to complete eradication. “Outbreaks are going to happen,” he said. The current eradication plan anticipates and budgets for them. Global capacity for rapidly subduing outbreaks has never been better. Indeed, the Somali outbreak could have received a different storyline, one of rapid and courageous response to a crisis.
Nigeria and Pakistan loom as far larger problems than outbreaks. It is not clear that case trajectories point enduringly down in those two countries. So far this year, cases number in the dozens, not the single digits that might augur eradication. And although Afghanistan represents a bright spot, it is inextricably tied to progress across borders with Pakistan where deadly attacks have been orchestrated against vaccinators.
The remaining obstacles are daunting but of a kind that have been overcome before. Even with outbreaks, eradication can and likely will be done.