Public health was born here — are we forgetting its lesson?

One of the greatest break throughs in public health took place not far from The Conduit Club.

In the mid-19th century, London’s population surged from 1.9 million to 2.8 million. Overcrowded slums and poor sanitation created a breeding ground for disease. Cholera outbreaks tore through the city, killing thousands. Between 1831 and 1866, more than 40,000 people died from the disease in London alone.

At the time, doctors believed cholera was spread by "miasma"—foul air trapped in low-lying, dirty neighborhoods. But a young doctor named John Snow had a different idea. He suspected the disease was spread through contaminated water.

In 1854, a devastating cholera outbreak hit Soho, killing over 600 people within weeks. Dr. Snow investigated the deaths and found that most victims had been drinking from the Broad Street water pump (now Broadwick Street). Crucially, the outbreak happened before a modern sewer system reached the area—meaning the drinking water was likely contaminated by cesspits and graveyards. After Snow persuaded authorities to remove the pump’s handle, the number of new cases dropped dramatically. His discovery changed the course of medicine and marked the birth of modern epidemiology.

Yet, more than 170 years later, cholera still kills. The World Health Organization estimates there are up to 4 million cases each year, causing as many as 143,000 deaths. Most victims live in low-resource settings and are children without access to safe drinking water.

The good news is that cholera is entirely preventable. The Oral Cholera Vaccine (OCV) is between 60–85% effective shortly after vaccination. In Haiti, the vaccine helped curb the deadly 2010 outbreak, with studies showing up to 97.5% effectiveness in vaccinated individuals. In South Sudan, over 4.1 million doses were distributed between 2024 and 2025, helping to bring down cases significantly.

However, new challenges are putting progress at risk. Climate change is increasing the frequency of floods and water stress in vulnerable regions, raising the threat of new outbreaks. At the same time, the WHO is facing a $600 million funding gap and expects a 21% cut in health spending over the next two years. This is already leading to clinic closures and job losses in over 70 countries.

Meanwhile, the global stockpile of cholera vaccines is nearly depleted. Only one company—EuBiologics in South Korea—is producing the vaccine, and no new suppliers are expected before 2025. As a result, health agencies have been forced to switch from a two-dose to a one-dose strategy, reducing long-term protection.

This is where action is needed.

On the 23rd of June at The Conduit we will hear from experts working in global public health about what we can do to make sure nobody succumbs to a preventable death from dirty water. In partnership with the Wellcome Trust, Our Climate and the Future of Health conference on 23rd will include a discussion on managing the health impacts of water stress lead by Gary White, CEO and co-founder of water.org as well as a preview of Janice Li’s exhibition on Thirst at the Wellcome Trust.

Please join me in person or online in what I am sure will be an exciting and information discussion.

illuminem Voices is a democratic space presenting the thoughts and opinions of leading Sustainability & Energy writers, their opinions do not necessarily represent those of illuminem.