Global Health and Foreign Policy Blog

During the first week of December (coincident with the opening of the United Nations Climate Change Conference in Bali) the Institute of Medicine’s Forum on Microbial Threats convened an expert meeting to explore the links between climate change and infectious disease. The event brought together a diverse group of experts from fields such as medicine, public health, ecology, plant science, remote sensing, agriculture, entomology, demography, and public policy to grapple with an important, but somewhat controversial, question within the overall climate change debate: will a changing climate lead to more infectious disease?

In seeking an answer to the general question, presenters tackled multiple perplexing sub-questions, such as: What are the mechanisms by which climate change leads to shifts in disease? How do human social factors interact with the ecological processes leading to shifts in disease? Which countries will be most affected and which will be spared? How potent are the tools that we currently have at predicting, identifying and ameliorating future changes in disease incidence? After two full days of rigorous discussion, it seems fair to say that participants found that clear, convincing answers to these questions were often hard to come by.

There is solid scientific evidence that increasing temperatures can lead to increased transmission of disease, through direct action on infectious agents (e.g. malaria parasites develop in the mosquito more rapidly in higher temperatures), effects on vectors (e.g. greater geographic range and longer active season for mosquitoes, ticks, etc), or changes in host behavior (e.g. shifts in migratory bird patterns). Rainfall and humidity also have proven biological effects. Not all the effects are negative – e.g. influenza virus transmission is reduced in humid, warm environments. In addition, the bulk of the negative effects will be concentrated at the “disease margins” – areas on the border of endemic regions are much more vulnerable to climate change.

While these biological effects can be proven, what is increasingly clear is that such changes will be dwarfed by the interacting variables of future human behavior in reaction to climate changes (urbanization, migration, and agricultural practices), and the pre-existing and future capacity of public health systems. A poor country with a weak health system and a large infectious disease burden will likely have a hard time adapting (or even identifying) relevant changes in disease incidence in the future, leaving it vulnerable to the effects of climate change. In contrast, a rich country with an effective, existing public health system is likely to respond well. Whatever the temperature is in Atlanta in the future, we are unlikely to ever again see endemic malaria there.

Putting yet another layer of perspective on it, one can note that the additional cases of disease likely attributable to climate change as predicted by our best forecasting models represent only a small fraction of the current global infectious disease burden. Why are we worked up about possible climate change-induced disease when we have totally unacceptable levels of disease right now? This viewpoint was captured beautifully by Dr. Donald Burke, the keynote speaker and main author of the National Research Council’s comprehensive 2001 report on climate and infectious disease Under the Weather, when he answered an audience member’s question about what guidance he would suggest for ministers of health in countries at risk for climate-aggravated vector-borne disease problems. Burke responded that countries could reduce and even eliminate vector-borne diseases with existing tools and knowledge, all it would take is adequate financial resources and political will. Thailand could end its dengue problem now, he said, and never have to worry about whether or not climate change will increase dengue in the future.

The point is that with or without climate-change induced changes to disease, we still need to focus on the fundamentals – good health systems, adequate surveillance, predictive capacity, health prevention, laboratory capability, transparency, and effective vector control. Concerns about climate change could raise awareness about weaknesses in these areas and could lead to corrective actions (which would be a welcome development), but a changing climate is will not be a principal determinant of the future global distribution infectious diseases in general. Poverty, lack of adaptive capacity, and human social factors (including trade and travel practices) will play a much bigger role and should be placed at the center of all these discussions of the health effects associated with climate.

An outside observer might get the idea that the US Congress is ignoring the international disease threat. Federal agencies have clearly indicated that these diseases pose a health threat and an economic and security risk to the country, but there is little evidence of a widespread push for better global disease surveillance around the world aside from the emergency earmarking of funds for (mostly domestic) influenza surveillance and the reshuffling of bureaucratic priorities within the government’s health-related agencies. In an effort to take the government’s commitment to a higher level (albeit still not commensurate with the threat), some lawmakers have introduced legislation aimed at improving disease surveillance around the world.

Senator Joe Biden (democrat from Delaware, and current aspirant for the democratic presidential nomination) along with co-sponsors Sen. Robert P. Casey, Jr. [PA], Sen. Chuck Hagel [NE], and Sen. Edward Kennedy [MA], introduced a bill titled “The Global Pathogen Surveillance Act” (S. 1687) to the Senate on June 25, 2007. The bill essentially requires that the United States provide funding and other support to bolster the infectious disease surveillance capacity in developing countries through: 1) direct monetary support of the World Health Organization’s efforts in the area, 2) earmarking scholarship support for foreign nationals to study in graduate programs in public health surveillance, laboratory science, and other related programs, 3) purchasing communication equipment for use by developing countries in support of disease surveillance, and 4) expand the programs and outreach of the already existing US HHS/CDC and DoD programs in other nations. The bill has been introduced in three separate congressional sessions—the first two times it failed to be introduced in the House of Representatives after being approved by the Senate Committee on Foreign Relations. See the original press release on the bill from Sen. Biden’s office here and the Congressional Budget Office’s (CBO) cost estimate for implementing the bill here.

Another bill (which tangentially overlaps the other bill) is the “Wildlife GAINS act” (S. 1246, H.R. 1405) introduced in the Senate in March of this year by Joe Lieberman, Sen. Daniel Akaka [D-HI], Sen. Jeff Bingaman [D-NM], and Sen. Samuel Brownback [R-KS] and introduced in the House by Rep. Rosa DeLauro [D-CT]. The bill seeks to “establish and maintain a wildlife global animal information network for surveillance internationally to combat the growing threat of emerging diseases that involve wild animals, such as bird flu.” Currently the bill is sitting with the House Subcommittee on Horticulture and Organic Agriculture and the Senate Committee on Health, Education, Labor, and Pensions without having been voted on. This bill is itself a re-working of a previous proposal (“The Global Network for Avian Influenza Surveillance Act”) that failed to get a full House vote during the previous congressional session. The CBO cost estimate for Wildlife GAINS can be seen here.

Making law is cumbersome and time-consuming, and many factors can determine success and failure. Still, the main culprit behind the inability to turn these bills into law can be probably attributed to a lack of popular understanding of their importance to protect US public health. As with so many other preventative, “global good” measures, investing in a longer-term solution comes at the expense of immediate political pressures. Probably it will take a serious health emergency to shock the public out of complacency, but hopefully these bills (or something like them) will be move beyond the subcommittee rooms of the capital and into become law before that occurs.

The world’s ability to prevent a devastating pandemic of influenza depends in large part on the willingness and ability of countries to share information, including virus samples, openly and quickly. A delay in detecting and reacting to an outbreak of human-to-human transmission caused by self-interested hoarding of samples or information could lead to thousands, if not millions, of otherwise avoidable deaths. That is why the pressure is on for the World Health Organization (WHO) to help countries iron out a possible impasse on bird flu sample sharing.

The tension originally arose from a group of countries, led by Indonesia, claiming intellectual property rights over flu virus samples originating inside their borders. For the last half-century, countries had freely shared influenza samples with the WHO, which then worked with various laboratories (including the US-based Centers for Disease Control and Britain’s Health Protection Agency) to isolate and study them. In some cases, the virus samples were used to generate “seed strains”, which would then be handed over to pharmaceutical companies so they could manufacture and sell influenza vaccines back to countries. Indonesia, which has recorded the highest death toll due H5N1 (avian) influenza, stopped sharing samples earlier this year saying that it required assurances that it would have access to any products developed using its samples. Other countries quickly joined the call for access to life-saving interventions generated using samples coming from their territory.

In response to the growing stalemate, the WHO convened a special working group meeting of 24 countries on July 31, 2007, whose goal is to generate recommendations flu virus sample sharing. While the task at hand is limited to flu samples, the repercussions of any guidelines could include other infectious diseases of international concern. Governments, pharmaceutical companies, intellectual property rights supporters, and public health representatives all have large, and somewhat opposing, stakes in the outcome of these discussions.

The developing nations’ concerns are legitimate. It would not be hard to imagine, especially in the face of an actual pandemic, that vaccines generated from Indonesian virus samples might be hoarded by rich countries where the manufacturing capabilities lie, or perhaps priced too high for poor countries to purchase enough to adequately protect their populations. On the other hand, any restrictions on virus sharing could hinder tracking the virus and developing necessary vaccines. If countries are allowed to share only on a limited basis, gaps in knowledge will result and the march of scientific progress will be slowed.

The WHO can be commended for taking rapid action on this complicated issue. The solution should fall heavily on the side of maintaining a robust scientific exchange on disease, because the cost (in lives and dollars) of a slow pandemic response far outweighs the potential loss of economic returns on a product. It will take skillful diplomacy to make sure that all stakeholders are working together to face the world’s biggest disease threat.

The new set of International Health Regulations (IHR), an update of the only international agreement on infectious disease control that is binding on WHO member states, will take effect on June 15, 2007. The arrival of the new set of rules has been heralded by some as a revolution in the fight against communicable disease and a high point for international health cooperation. While there is every reason to believe the new IHR represent an important step forward, it is also clear that they will not (and cannot) fix long-standing weaknesses in the international public health system. Until deeper problems are addressed, the IHR will remain a well-intentioned, but incomplete, instrument of global public health.

There are two key improvements in the new version of the IHR. First, it greatly expands the scope of internationally notifiable diseases. While only three diseases were reportable to WHO in the previous IHR (cholera, yellow fever, and plague), the revised version requires reporting on any event that constitutes a “Public Health Emergency of International Concern.” This theoretically requires countries to notify WHO of all existing and any new infectious diseases with a potential to spread internationally. Second, it allows for the inclusion of non-state information in notifications of disease outbreaks. Previously, WHO was constrained to reporting only disease outbreaks that had been officially recognized by the country experiencing the outbreak. The new IHR allow WHO to use third-party information (such as reports from other countries or from non-governmental sources) to publicly identify outbreaks even without official verification from the affected country.

While these changes are needed and are very welcome, there are two major problems contributing to global disease insecurity that the new IHR do not remedy.

First, disease surveillance capacity in many countries is poor to non-existent. The security provided by a global public health system is dependent on the effectiveness of its component domestic systems to provide timely and effective epidemiologic information, and many countries struggle to identify and track diseases. The new IHR acknowledge this weakness and urge rich countries to “provide support to developing countries…if they so request, in the building, strengthening and maintenance of the public health capacities required under the IHR”, but no solid, enforceable mechanisms for coordinating such a development program is outlined.

Second, the global health system is still comprised of sovereign states that place their own interests above all else. Mistrust and concealment is still a problem among countries and between countries and the WHO. For example, despite the looming threat of a devastating worldwide avian influenza pandemic, human and animal cases of the disease regularly go unreported, and some countries have been reluctant to share samples of the virus. Often, the reason for the lack of transparency is a fear of the negative economic repercussions from reporting a disease outbreak, which could lead to travel restrictions or a ban on exports. No effective measures currently exist to provide a counterweight to these often legitimate national concerns, and therefore secrecy will continue to hamper global disease control.

The IHR may represent an important health diplomacy tool, but the solution to the problem of international infectious diseases lies in addressing the global goods problem of funding the development of a true global capacity to identify and track diseases, as well as creating a responsible framework for incentives for countries to communicate quickly and openly about disease outbreaks. These solutions will not come from one international treaty, but from an extended multilateral effort with leadership coming from rich countries who realize that the best way to protect themselves from infectious diseases is to create a truly global disease control system.