Aylward at JHSPH: Eradicating Polio
On Friday, September 27, Johns Hopkins Bloomberg School of Public Health held its annual Vaccine Day. Bruce Aylward, MD, MPH, Assistant Director-General, Polio, Emergencies and Country Collaboration, World Health Organization, gave the keynote address. His title was "Eradicating Polio: Is the Juice Worth the Squeeze?"
Aylward’s riveting Ted Talk explores similar topics, and so I won’t summarize much of what he discussed. But his picture of the economic benefits of polio eradication was quite interesting. Aylward noted that “It’s not enough that the cost benefit ratio is positive. It has to be very much in favor of the benefits, because the risks to failure are high.”
Smallpox eradication provides a model for estimating the cost/benefit ratio of eradication. Aylward noted that the US saved about 159 dollars for every 1 dollar spent on eradication. For the international campaign, the ratio is about 400:1. And the United States recoups its financial investment in the smallpox eradication campaign every 26 days. So, he asserts, smallpox eradication was unequivocally worth the “squeeze.”
In 1988, the year the World Health Assembly resolved to eradicate polio, 350,000 children were paralyzed by polio, and it was endemic in 125 countries. The assembly’s resolution cited the potential benefits of eradication, among them being the reduction in diseases and deaths, monetary savings, and improvement of health systems. At the time, the WHA estimated that the eradication campaign would cost a few hundred million dollars. (To date, about $10 billion has been spent, and the new estimated cost of eradication is around $16 billion.)
But, Aylward, asked, what’s the juice? What benefits will accrue from eradication?
Direct benefits of eradication are that 1.5 million deaths will be averted, as will be 7.5 paralytic cases of polio. A 2010 study showed that eradication will result in $50 billion savings over next 20 years, much of that accruing to the poorest countries.
Indirectly, eradication efforts are resulting in expansion of health services. Vitamin A supplementation, for the prevention of blindness and nutritional deficiencies, has been combined in many countries with polio vaccination. This effort will likely produce billions in additional savings over the next 20 years. Other interventions have been piggybacked onto the polio immunization infrastructure: distribution of bed nets in malarial areas, administration of measles vaccine, swine and avian flu surveillance, a global laboratory network. Finally, the meticulous microplanning that underpins the eradication efforts leads to better identification of problems, such as who’s at risk, and how teams get vaccine to the specific children at risk.
But is there a danger that polio immunization efforts are interfering with routine immunization? Aylward cited the case of Bihar, in India: it had very low routine immunization coverage and was a big challenge for polio eradication. As the OPV campaigns concentrated on this area between 2006 and 2010, their routine immunization coverage tripled. In Africa, DTP-3 coverage has gone up 40% from 1988, when rates were stagnant, indicating that polio campaigns have not detracted from routine immunization efforts.
So, the economic and indirect benefits of eradication and its accompanying activities are real. But is it realistic to think that polio truly can be eradiated?
We’ve certainly seen a huge reduction in paralytic polio since the 1988 declaration. Wild type 2 polio was eliminated in 1999, and we have not seen a case of wild Type 3 since the end of 2012. To date this year, there have been 270 cases of wild polio, with 79 in endemic countries and 191 in non-endemic countries.
But recent polio outbreaks in Tajikistan, Democratic Republic of Congo, Somalia, Egypt, and Kenya illustrate the dangers of importation of virus from neighboring, still-endemic countries. The World Health Assembly responded to importations into nonendemic countries in May 2012 with a declaration of an emergency for global public health.
The polio endgame plan for 2013-2018 was launched several months ago and include several goals: detect and interrupt poliovirus transmission, strengthen the Expanded Program on Immunization and withdraw first OPVs and then IPV, contain polio and certify eradication; and conduct legacy planning.
(I’ve written before about the problem of circulating vaccine-derived polioviruses; I won’t get into that here, except to say Aylward seems confident that the rollout of IPV along with bi- or monovalent OPV will address that problem.)
Security challenges, however, have emerged that may complicate the eradication plan. In Pakistan, 15 polio workers were shot dead, and 9 have been killed in Nigeria. In light of these challenges and resistance to vaccination, the WHO has emphasized engaging the Islamic world in its polio efforts. They have established an Islamic Advisory Council and forged a partnership with the Red Cross and Red Crescent to be able to operate in conflict-affected areas where those groups already have a permanent presence.
Aylward concluded by bringing up the concept of the fifth child: that hardest-to-reach child in a remote or conflict-ridden area whom previous vaccination campaigns have failed to find. He estimates that only about 20 districts in the world hold the key to polio eradication, and that there are 250,000 missed children in Nigeria, 25,000 in Afghanistan, 500,000 in Pakistan, and 500,000 in the Horn of Africa. We can’t eradicate polio without getting to those missed children. And those missed kids are missing much more than a dose of OPV: they are lacking other vaccines and basic health care, sanitation, and education. Someone, he said, needs to be accountable for getting the most basic services to them. Aylward finished by quoting smallpox eradication trailblazer William Foege: “Eradication attacks inequities and provides the ultimate in social justice.”