Swan: I think there are a few things going on. We may have more media attention for disease reporting and we could gain more public awareness about the potential of a new outbreak to affect our lives. They are generally positive.
On the other hand, I think we’re seeing disease trends that matter, in terms of new diseases (e.g. from the Zika virus), diseases that affect new populations or transmit them in new ways (e.g. monkeypox), and recurrent diseases that almost eradicated (eg polio). I expect these to continue in the coming years. We have almost 8 billion people in the world and that is expected to grow to almost 10 billion by 2050. We have an increase in natural disasters that can lead to displacement of people and animals, putting them in critical contact. Compared to previous centuries, the level of travel and connectivity worldwide is astonishing. 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. We also don’t spend enough of our resources on disease prevention in the US and worldwide, and we find ourselves doing our best to respond to new, preventable or neglected diseases. Unfortunately, I expect this to become the ‘new normal’.
Koci: The answer depends on what disease you are talking about. The new diseases are the hardest to know for sure. Some of it is just bad luck. The wrong person comes into contact with the wrong wild animal infested with a species that happens to be quite capable of jumping on humans. The more people move into previously wild areas, the more the number of these interactions increases, the more likely that this will happen year after year.
Then we have diseases that are not new, but historically they have only occurred in one region of the world and now they are moving into new areas. Dengue fever, chikungunya and Zika are good examples of these types of diseases. As the mosquitoes carrying these viruses move to new geographic areas, they bring the viruses with them. This will only get worse as climate change allows these insects to continue to expand 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 been using antibiotics for too many years. Human medicine, veterinary medicine and agriculture are still bickering about who deserves the most blame, but right now it doesn’t really matter. We’ll soon run out of antibiotics that work, and it’s increasingly likely that we’re going back to a world where any simple scratch or puncture can lead to a deadly infection.
Finally, we have the maddest of all reasons: the growing anti-science and anti-vaccine movement. We’re seeing a return of things like polio and measles, diseases that we had under control in the US. The anti-vaxxers have been getting a lot of press over the past two years regarding the COVID-19 vaccines, but they have really worked hard to undermine these life-saving tools for much longer, whether it was Jenny McCarthy on Oprah in the 90s, or Facebook groups in the past 20 years. COVID-19 just gave them a chance to focus on their anti-scientific rhetoric. Along with intravenous tubing and blood transfusions, vaccines are among the top three medical advances in all of human history. They are credited with saving over a billion lives.
The data on the effectiveness of vaccines as a public health tool is undeniable. But the real power of vaccines in public health is that when everyone who can be vaccinated, they ultimately protect those who can’t. That system of taking care of each other is why measles, mumps, rubella, diphtheria, whooping cough, polio, smallpox, and tetanus are all rare to non-existent in the US. It’s infuriating that a handful of people trying to make money selling conspiracy books and quacks have gained enough followings that we’re now seeing a return of some of these diseases. If these trends continue, we may see more coming back.