Vertical and Integrated Approaches: Does Acute Flaccid Paralysis (AFP) Surveillance Support the Health System?

SVEA CLOSSER: Up to now throughout this whole section of the course, we’ve been considering surveillance for polio as if it existed in a vacuum. But polio is not the only surveillance need of countries like Nigeria and DRC. Many other diseases, from Ebola to measles to cancer, affect these populations. Polio eradication has an unmatched and unprecedented global surveillance system. The Global Polio Eradication headquarters in Geneva is responsible for polio surveillance and monitors and collects surveillance data on AFT from everywhere in the world. Overall, this system combines global reach and active surveillance quality in a way unmatched by any other system in the world and probably by any surveillance system in history.

AFP surveillance systems across the world, as we’ve discussed, aren’t perfect, but in general, they’re characterized by high quality, active surveillance visits, extensive additional staff, often funded by WHO, and lab facility support, often constructed by the Polio Eradication Initiative. Though the exact mechanisms differ, the AFP surveillance systems are often managed by WHO staff at the national level and have historically had AFP surveillance as their sole focus or their primary focus in most countries. At the same time, right alongside this big huge global polio surveillance system, countries have surveillance systems for other diseases as well. And these systems across the whole world of course range widely in quality from excellent to completely defunct.

And these systems generally have not gotten the international support and funding that has been given to polio surveillance. For example, the DRC system is adequate for a few diseases but not for many common killers. So if you think about the surveillance system in your own country, are there any other diseases that have as good a system as polio? And are there diseases whose systems really need strengthening? You may or may not know the answers to these questions. But in almost any country, there are some trade-offs. Surveillance is expensive. You can’t do it for every disease. So countries have to make decisions about what they’re going to do.

So the issue here is that often for countries, funding may be available for polio surveillance in a way that it’s not available for surveillance for other diseases. So in many countries, what’s happened is you have this very high quality polio surveillance system that may coexist alongside not great surveillance systems for diseases that might kill way more people in a given population. Given this issue, it’s really important to think about whether the polio surveillance system could be used to improve surveillance for other diseases too. And this doesn’t directly benefit polio eradication, but it can have a huge impact on reducing morbidity and mortality from other diseases if countries can learn where these diseases are happening.

So many countries across the world have been successful in building some additional disease surveillance onto the AFP system. So this particular graph here shows that, over time, in seven African countries– Angola, DRC, Cote d’Ivoire, Ethiopia, Nigeria, Tanzania, and Togo– more and more diseases were integrated into the polio surveillance system. So in the late ’90s when the AFP surveillance system was relatively new in these countries, it was just looking for AFP. And 15 years later, by 2014, a lot of other diseases had also been integrated into the polio surveillance system in many cases, including things like measles, cholera, meningitis, rabies, issues that affect a lot of people.

Despite this overlap, sometimes surveillance protocols for AFP and other diseases may not be fully integrated. For example, a surveillance system may use different monitoring and reporting personnel, protocols, and procedures to track suspected cases of various diseases. And this happened especially if those diseases have different internationally funded reporting requirements. So for example, measles, which has a different global initiative to eliminate cases, has its own reporting requirements that come from an international level. AFP has reporting requirements that come from the GPI and so on. So these different global requirements can make it difficult for countries to really integrate systems in a way that makes sense. And this can lead to a really inefficient use of worker time at the ground level.

So you may have community health workers that are responsible for surveillance filling out completely different forms and sending them to completely different places for different diseases even though they’re looking for these diseases in the same population. So frontline workers are critical in thinking about building good surveillance systems. And in Nigeria, building the capacity of these frontline workers to do surveillance has been something that polio eradication has focused on. So when they are doing campaigns, health care workers get trained on surveillance as well, particularly in conflict regions.

And they’re trained not just about surveillance of polio but surveillance of other diseases as well and also some information about the provision of health care services that they can pass on to community members. In Nigeria, the emergency operation center, which is designed to support polio eradication, has also been used by other disease control programs including when there was an Ebola epidemic. So there are ways that various countries have built other surveillance capacity onto the polio system, but it tends to be on the initiative of the countries themselves and wasn’t built into the way that the polio surveillance system was designed from the start.

Beyond frontline staff, there’s also been an effort to build capacity in Nigeria for other kinds of surveillance staff. So the African Field Epidemiology and Laboratory Training Program trains field workers across levels of the system. And NGOs in Nigeria have been conducting training for a variety of staff participating in campaigns and also in surveillance. At a more basic level, there’s been some training at universities as well. Similarly in the DRC, in collaboration with the CDC, two programs have been established to train disease detectives. At universities, there’s now a two year MPH in field epidemiology and laboratory training and an accelerated training program for frontline workers.

These trained disease detectives collaborate with the Ministry of Health and WHO to search for and investigate cases of AFP in areas with outbreaks. And they’ve been instrumental in containing these outbreaks in a timely way. It can be challenging to really integrate polio and national surveillance systems. Sometimes countries have been reluctant to rely too much on the AFP surveillance system because it’s seen as inherently unsustainable. Given that it’s supported nearly entirely by external funding and that external funding is tied to polio, some countries fear that once polio is eradicated, the surveillance system will disappear.

They also fear if they build too much of their other surveillance onto the system, those surveillance systems for other diseases might also be hurt if polio goes away. So in many countries with very, very weak surveillance systems, the WHO created a high quality parallel system for polio surveillance. But often a lot of other diseases weren’t included in that because of the fear that the system might deteriorate in the absence of foreign investment. So DRC is one example of the challenges of a parallel system. Because the polio system was focused on polio and not other vaccine preventable diseases, remaining coverage gaps in routine immunization have left the DRC susceptible to vaccine-derived polio.

Without continued investment, and improving routine immunization, and maintaining disease surveillance systems for a range of vaccine-preventable diseases, it’s been difficult to eradicate polio. The takeaway here is that future initiatives should consider ways to leverage their program resources to improve health systems in a broad way rather than drawing internal resources away from other health priorities. In addition, vertical disease control programs should be careful about creating alternate structures which temporarily maintain health system functions without enabling the requirements for sustaining those functions once program goals are met. This is a challenging mandate. And that’s why it hasn’t happened in a lot of vertical programs but it’s particularly important when working in contexts with relatively weak health systems.