Expert Interview: Global Polio Eradication Is Within Grasp

Bruce Aylward, MD, MPH, assistant director-general for polio of the World Health Organization, discusses recent progress in global polio eradication. Image: World Health Organization.

Bruce Aylward, MD, MPH, assistant director-general for polio of the World Health Organization, discusses recent progresses in global polio eradication. Image: World Health Organization.

The eradication of polio is within the world’s grasp in the next 5 years, according to the world’s leading expert on polio.

Bruce Aylward, MD, MPH, assistant director-general for polio, emergencies, and country collaboration of the World Health Organization, made his remarks yesterday at a World Polio Day 2013 event in Chicago. The event, organized by Rotary International and Northwestern University’s Center for Global Health, convened an international panel of polio experts and advocates to discuss the latest progress of the Global Polio Eradication Initiative, the global effort to make polio the second infectious disease affecting humans to be vanquished, after smallpox.

The initiative is a public-private partnership that includes the World Health Organization, Rotary International, the US Centers for Disease Control and Prevention, and UNICEF. They have recently developed a Polio Eradication and Endgame Strategic Plan that delineates a long-term strategy for conquering polio.

Before the session, news@JAMA spoke with Aylward about the latest progresses in polio eradication and the goals of the endgame plan.

news@JAMA: If there is one important message about polio that you want to convey to the global health community right now, what would it be?

Dr Aylward: Seize the moment. Finish polio once and for all. That would be the overriding message.

news@JAMA: And where do you think we are on that path?

Dr Aylward: We’re in a fantastic position. When we set out to eradicate polio, there were 1000 kids a day being infected, and we’re now down to maybe 1 a day. Also, initially, there were 3 types of polioviruses—types 1, 2, and 3. In 1999, we saw the last of the type 2 virus, and in November 2012 we saw the last of type 3. So 2013 has been the first year where we’ve only seen 1 type of poliovirus.

Also, this year, every single case of polio in the world is due to virus that originated from either one corner of Pakistan or one corner of Nigeria. This is the first time in history that we’re down to just 2 hot spots, so we’re in a good place right now. The problem is, of course, that these small hot spots continue to reinfect other countries that were previously polio-free. That’s why the World Health Assembly declared polio to be a global health emergency last year and since then has stepped up the global efforts for eradication.

news@JAMA: I’m curious about issue of wild poliovirus vs vaccine-derived virus. How often does vaccine-associated polio occur and how much of a setback is that causing?

Dr Aylward: Vaccine-associated paralytic polio, or VAPP [which is when a child who is vaccinated with the live oral polio vaccine either gets the disease or infects a close contact], is very rare—1 in a million doses. There are probably about 250 to 450 cases per year based on that incidence rate of 1 in a million. Vaccine-derived polio outbreaks are even more rare than VAPP, maybe 3 or 4 a year, but those are what usually get reported rather than the individual VAPP cases.

news@JAMA: Are the individual VAPP cases counted in the global case counts then?

Dr Aylward: Not usually, because they’re very difficult to diagnose clinically and are rarely reported.

news@JAMA: Interesting.

Dr Aylward: This was one of the factors taken into account when developing the Polio Eradication and Endgame plan. On this World Polio Day, this is the big thing that is different from previous years: there is a new endgame plan for eradication, just released by the World Health Assembly in May 2013; the ink is still wet.

news@JAMA: Can you explain the endgame plan?

Dr Aylward: The plan is to eradicate the wild poliovirus and in parallel tackle vaccine-derived poliovirus. We’ll switch the oral polio vaccine from the current trivalent vaccine [which protects against types 1, 2, and 3 of poliovirus] to a bivalent vaccine, which protects against types 1 and 3 only, because the type 2 component of the vaccine causes 95% of VAPP outbreaks. At the same time, we’ll give a dose of the injectable polio vaccine [which is not associated with VAPP because it is an inactivated vaccine, unlike the oral polio vaccine, which is a live vaccine] to protect against type 2 poliovirus and for general hyperimmunity to help finish the job.

news@JAMA: That sounds like a very smart and promising plan.

Dr Aylward: Thank you. It’s an extremely ambitious plan but it will ultimately be win-win-win.

news@JAMA: So you think the last case of polio will be vaccine-derived then?

Dr Aylward: Oh goodness, I’ve never thought about it that way. I certainly hope not, but it might be.

news@JAMA: Realistically, when do you think the world can be polio-free?

Dr Aylward: I think 2018 is a completely realistic time frame.

news@JAMA: That’s great—and more optimistic than I expected.

Dr Aylward: I guess you have to be [optimistic] to eradicate. I think right now, we still have more things to throw at the virus than it has to throw at us. It’s a battle, but we are closer than ever before. In this day and age, there is no reason that we can’t wipe out this disease forever.

Categories: Immunization, Infectious Diseases, Public Health, Viral Infections