Josh Rosenthal, PhD: Fogarty past & present
May/June 2025 | Volume 24 Number 3
Photo courtesy of Josh RosenthalJosh Rosenthal
Joshua Rosenthal, a senior scientist in Fogarty’s Division of Epidemiology and Population Studies, retired from Fogarty on March 31. After completing a PhD in Botany at the University of California, Berkeley, he conducted his post-doctoral research in Entomology and then joined Fogarty as an AAAS Science and Diplomacy Fellow in 1994. Over the course of his career, he served as the center’s interim deputy director, deputy director and interim director of the Division of International Training and Research, and a program officer.
Why did you become a scientist?
I always liked science when I was young. But there were no scientists among my family and I never thought seriously about the natural sciences until I was in college. I went to Pitzer College in Claremont, California, thinking I would study anthropology, but became interested in international development and the environment. While on a study abroad program in Sri Lanka, we were looking at various approaches to agriculture, and I began to realize that I couldn't understand the questions I was interested in without more biological understanding. So after graduating I sought out a PhD program that would allow me to focus on ecology of agricultural and natural systems, and landed at UC Berkeley where I did research on plant resistance to insects for my doctorate and postdoc. I came to Fogarty on AAAS Fellowship to work in natural products drug discovery and conservation through the recently launched Biodiversity program … and I never left!
What are you most proud of about your time at Fogarty?
After an exciting 30 years that’s difficult to say. Because Fogarty is such a creative place full of dedicated people willing to take risks, I’ve had the opportunity to do lots of things - from biodiversity based drug discovery to ecology of infectious diseases, international training and research in environmental health, household air pollution, implementation science, and climate health. In terms of scientific impact, perhaps our creation of the Ecology and Evolution of Infectious Diseases program with the NSF and several NIH institutes has been among the most transformative, and I am thrilled that this 25 year old partnership with multiple agencies has continued to this day.
How did you get involved with the GeoHealth hubs?
The Environmental Training Research and Environmental Occupational Health Research program was a very traditional toxicology and epidemiology focused program doing valuable work training scientists in LMICs. But the projects were small and at the end of a grant, these individually trained scientists were left disconnected in disparate places around the world. It wasn't clear that we’d produced any institutional impact. Christine Jessup, a Fogarty program officer, and I wanted to develop a program that was better networked, more institutionally based and more trans-disciplinary. We came up with this notion of hubs that would link to multiple institutions in the U.S. and abroad. To build-out each hub, we gave a research grant and a training grant in parallel within a networked environment. It's still too early to know, but some of those projects have already generated follow-on investments from Canadian and European organizations and other parts of the NIH, so I hope the science and the capacity that's been created will have longstanding impact.
Tell us about the Household Air Pollution Intervention Network (HAPIN) Trial.
I was a great fan of UC Berkeley’s Kirk Smith, who had spent decades trying to to reduce the health impacts of household air pollution caused by cooking with solid fuels. Observational studies showed that people who cooked with cleaner fuels were healthier than people who cooked with polluting fuels, and there were lots of programs under way to support an energy transition. However, there had been only one RCT on health benefits of switching to cleaner fuels and it had yielded less than conclusive evidence for severe childhood pneumonia. The HAPIN trial, with support from across the NIH and the Gates Foundation, was an attempt to answer the question:
Could you make an intervention for impoverished settings and homes that would yield measurable impacts on severe infant pneumonia, birthweight, and stunting at age one and also blood pressure in adult women?
The HAPIN trial grant that was awarded was rigorous in design, practical, and well run by a first class group of scientists in four host countries: India, Guatemala, Rwanda, and Peru, and the US. In parallel to the trial, we made significant strides with a smaller effort, the Clean Cooking Implementation Science Network, to understand uptake and scale up of clean fuels. However, the trial outcomes were a bit disappointing. The RCT results were null for all four primary outcomes, although we did see an exposure - response relationship for birthweight, when the randomization to treatment is broken.
But that’s science. You don’t always get the results you hope for. The integrity of the pursuit requires that we accept null outcomes with transparency and go back to the drawing board. Almost nobody doubts that chronic exposure to air pollution causes a lot of disease and early death, so the question becomes what is the most effective and cost effective way to reduce exposures to yield the greatest health. And there is lots to do to figure that out.
What has changed over time at Fogarty?
A lot has changed! When I came to Fogarty, Ken Bridbord (then a Branch chief) had begun to develop ground breaking international AIDS research training, and there was this new Interagency Biodiversity program I mentioned, but other wise it was a quiet, less ambitious place mostly focused on fellowships and support for other ICs. Since then, we’ve become a much more science-forward organization with greater ambitions focused on larger problems in global health. Its been amazing when I look back at it.
One of the keys to our growth has been our own awareness of the close relationship between global health and the health of U.S. populations. We've also become more rigorous and much more strategic in making those connections. This strategic focus accelerated under Fogarty Directors Gerry Keusch, Roger Glass, and Kathy Neuzil.
What is the connection between American health and global health?
Most people in the U.S. don’t pay attention to health conditions outside the country. Occasionally, epidemics like those of HIV AIDS, Ebola or COVID raise awareness, but we tend to think of those problems as “overseas”, until they threaten us. But today we are so connected that every health challenge and discovery in the developing world has either direct or indirect applications to health in the U.S., whether they're related to infectious or chronic diseases, or environmental in origin.
The U.S. is still the strongest country in the world scientifically, yet it’s necessary to work with those who have expertise and deep knowledge about topics and environments that are less familiar here. These partnerships expand our own capacity to deal with problems that are here today and/or will be in the future. And when our partners are better scientists we are better as well.
For example, most people have forgotten that malaria was once endemic in the U.S., and now, once again, we have transmission of both malaria and dengue in the U.S. Because we have spent years investing in the study of malaria and dengue overseas, we’ve learned a lot about the biology of those diseases and how to manage them. The chance that they'll be able to embed themselves and become major health problems here are much lower because we understand how to reduce exposures, how to control the vectors, how to treat the diseases or vaccinate against them—all due to the extensive, painstaking work we’ve done overseas.
What are your plans for retirement?
I spend a lot of time birdwatching and woodworking. There are some teaching opportunities and research opportunities. So probably a mixture of all of those things, I'm not sure yet.
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Updated June 18, 2025
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