Climate Change and Public Health Dinner Discussion with Professor Metcalf

by Andrew Wu

Climate change has many implications for public health, particularly on the transmission of infectious diseases. Changes in humidity can lead to an increased risk of illnesses that spread through bodily fluids. Vectors such as mosquitoes can become more abundant and affect larger regions. Natural disasters can destroy healthcare infrastructure, decrease the immunity of a population, and increase exposure to water-borne diseases. Although there are many factors that modulate infectious disease dynamics, it is crucial that we understand how our health and well-being will be transformed by environmental changes, as they become more drastic and prominent in our lifetimes. Recently, we met with Professor Metcalf of the Ecology and Evolutionary Biology and Public Affairs departments to discuss her research and expertise in this area.

One of the main aspects that Professor Metcalf emphasized about her endeavors was the heavy amount of detective work involved. Much of this problem comes from the lack of data. She remarks, “The data is shaky and sometimes you don’t write down certain things. Sometimes it might not reflect what you care about . . . The point is, the data is never as good as you’d like.” This issue extends to journals and databases as well. Professor Metcalf adds, “There doesn’t seem to be enough focus on climate change and public health. The New England Journal of Medicine’s editor allegedly doesn’t believe in climate change. The National Institute of Health has studies on environmental health, but they’re all on air pollution. There are no infectious disease studies.” Researchers often face the difficult situation of having available data that is biased or not having the proper surveillance equipment in order to gather precise information. For example, signals sent from mobile phones can be used to create a map depicting how various populations are travelling. In Bangkok, there is excellent precision due to a high density of cell towers. However, in Kenya, the towers are miles apart, which creates unreliable data. A related problem is the careful statistical analysis needed to identify an association between climate events and infectious disease dynamics. Professor Metcalf comments, “There are big fluxes throughout a year. Sometimes the data is very clear, which is always helpful. For example, in Manjuli, there is a 30-60 day oscillation in the rainfall. That helps you build a more reliable model. Epidemiology all depends on a mechanistic model, which factors in disease incidence and susceptibility. Usually it’s a semi-mechanistic model, so you layer machine learning for what you don’t know. You have to work with different datasets at different resolutions. Everything goes up and down in a year, so it’s important to identify the cycles. ” Her work has led to several discoveries, including the relation between transmissions in schools and child infections. In addition, she related fluxes in climate to rubella transmission. She comments, “It’s harder to pull out those signals because sometimes there are so many factors. The bottom line is, can you figure out where they’re [people] going?”

Second, Professor Metcalf discussed the role of communication and collaboration in the scientific community and their importance in her field. She has worked with climate scientists in order to combine the disciplines and gain a better understanding of the phenomenon. However, it is not always easy, since the groups have their own perspectives of what is the larger issue. Professor Metcalf comments, “It’s hard to work with climate scientists. Each thinks that they’re doing the harder work than the other.” It is clear that communication plays a clear role for researchers as they branch out to different fields. This is also true when she is advocating for her research or applying for a grant. She says, “The rhetoric I tend to use is focusing on the importance of my research.” When asked about the role of public and private institutions in addressing public health and climate change, Professor Metcalf responded that both sectors were crucial. Of course, each organization has its own agenda and it is important that all of them find a way to work together. She explains, “There’s a lot of funding that comes from the Gates Foundation and the Wellcome Trust, it’s huge! The World Health Organization (WHO) heads the rubella and measles vaccination efforts. On the other hand, Gates cares less about climate change and wants immediate technical solutions. Bill Gates really matters, just twitch of his
eyebrow can change something, but I think he wants to focus on polio first. I think there’s a lot of potential in the private sector, but the Gates Foundation is bizarre. It’s essentially all under the whim of one man and I’m not sure that’s a good approach to addressing this issue. Of course, it’s done a lot of good and I have received funding from them for my research. I always look forward to hearing the foundation’s latest impact because there’s no doubt it’s made excellent progress.”

We continued to explore her research in other countries and a variety of other topics. Some of Professor Metcalf’s focuses on Madagascar, where she grew up. She describes the public health situation in the country, “Climate change is a big issue because it prevents health systems from functioning. Cyclones take out health centers and vaccines are disrupted when they are most needed. Routine vaccinations don’t even work. There are children who never have the chance to vaccinate. The easy fix is just to increase eligibility. The upper age for vaccines in the WHO is only 12 months, when it could be increased. We ought to focus on health systems resilience by anticipating more intense cyclones and preparing for them.” There was discussion about Puerto Rico as well, regarding how to spread information about available vaccinations. Furthermore, there may be a need for new storage technology (e.g. vaccine patch) in order to adapt to the effects of natural disasters. In Pakistan, live vaccines are not as effective, but there are efforts to link the tetanus toxoid with the serum in order to make it more effective. Unfortunately, strong vaccination campaigns can lead to a lowered incentive to vaccinate. Professor Metcalf speaks more about this psychological phenomenon, “Sometimes people say that we stirred up all this uproar for a disease epidemic that never came. It’s because of good vaccination and herd immunity. When you’re preparing for cyclones, the storm sweeps by and you can see the devastation left behind. If people are properly vaccinated, there will be little incident of disease, making them believe they don’t have to vaccinate in the future.” It is clear that her work is filled with obstacles, but the research done by the Metcalf Lab will prepare us for an ever-changing world. As the climate becomes more drastic, we must seek to understand its consequences and how might we adapt to them.