Swan: I think there are a few things going on. We could draw more attention from the media to disease coverage, and we could have more public awareness of the potential of a new outbreak affecting our lives. These are basically positive.
On the other hand, I think we’re seeing important disease trends related to new diseases (e.g., caused by Zika virus), diseases affecting new populations or transmitted in new ways (e.g., monkeypox), and recurrent diseases almost eradicated (e.g. polio). I assume that these will continue in the years to come. We have almost 8 billion people in the world and this number is projected to grow to almost 10 billion by 2050. We have an increase in natural disasters that can result in the displacement of people and animals and put them in critical contact. Compared to previous centuries, the scale of global travel and connectivity is astounding. Science has provided us with effective vaccines for some diseases like polio, although the (unnecessary) increase in vaccine hesitancy leaves communities vulnerable to preventable diseases. Also, we are not adequately focusing our resources on disease prevention in the United States and around the world, and we must strive to respond to emerging, preventable, or neglected diseases. Unfortunately, I expect this to be the ‘new normal’.
Koci: The answer depends on what disease it is. The new diseases are certainly the most difficult to detect. Some of it is just bad luck. The wrong person comes in contact with the wrong wild animal infected with a strain that happens to be good at jumping on humans. As more people move into previously wild areas, the number of these interactions increases, the more likely this is to happen every year.
Then we have diseases that are not new but have historically only appeared in one region of the world and are now encroaching on new areas. Dengue fever, Chikungunya, and Zika are good examples of these types of diseases. As the mosquitoes that transmit these viruses move into new geographic areas, they bring the viruses with them. This will continue to get worse as climate change allows these insects to expand further where they can survive.
Then we have antibiotic-resistant bacteria. The causes of antibiotic resistance are complicated, but the short version is that we have overused antibiotics for too many years. Human medicine, veterinary medicine, and agriculture still argue about who deserves the most blame, but that doesn’t matter here. We are rapidly running out of effective antibiotics, and it is increasingly likely that we will return to a world where any simple scratch or puncture can result in a deadly infection.
Finally, we have the craziest reason of all: the growing anti-science and anti-vaccine movement. We’re seeing a return of things like polio and measles, diseases that we controlled in the US. Anti-vaccinationists have gotten a lot of press related to the COVID-19 vaccines over the past two years, but they’ve really worked hard to undermine these life-saving tools for much longer, whether it was Jenny McCarthy oprah in the 90s or Facebook groups in the last 20 years. COVID-19 gave them just the opportunity to take center stage on their anti-scientific rhetoric. Vaccines are among the top three medical advances in all of human history, along with indoor installation and blood transfusions. They are credited with saving over a billion lives.
The data on the effectiveness of vaccines as a public health tool is indisputable. But the real public health power of vaccines is that if everyone who can be vaccinated does, they will ultimately protect those who cannot. This mutual watching system is why measles, mumps, rubella, diphtheria, whooping cough, polio, smallpox and tetanus are rare or non-existent in the United States. It is outrageous that a handful of people trying to make money selling conspiracy books and quackery drugs have gained enough followers that we are now seeing a return of some of these diseases. If these trends continue, it’s possible more will come back.