Since Covid-19 engulfed the world two years ago, “unprecedented” has become something of a buzzword. But while the coronavirus has posed unique challenges at a time of deep global interconnectedness, pandemics are nothing new. The Covid-19 pandemic is not even the only one we are currently experiencing. In much of the developing world, cholera outbreaks are proliferating.

Whereas the SARS-CoV-2 virus is “novel,” cholera—a water-borne diarrheal disease caused by the bacteria Vibrio cholerae—is ancient, as is its history of widespread devastation. The current cholera pandemic is the world’s seventh since the early 19th century.

Despite their apparent differences, Covid-19 and cholera have much in common. Both are at least partly controllable by vaccination, and both spread most easily in crowded, unsanitary environments. Ensuring adequate shelter and strengthening water, sanitation, and hygiene (WASH) practices and infrastructure are therefore vital to limit transmission.

These commonalities explain why measures to limit Covid-19, such as decreased travel and increased vigilance regarding personal hygiene, brought about a decline in cholera cases. But as the world’s governments roll back pandemic restrictions, cholera is returning with a vengeance. At the end of 2021, there were 16 active cholera outbreaks around the world.

Yet the response to Covid-19 still holds valuable lessons for bolstering the fight against cholera—beginning with the importance of research to combat disease outbreaks. The emergence of SARS-CoV-2 triggered a massive and largely coordinated global research push, which enabled evidence-based decision-making at all levels of prevention and control. Initiatives like the World Health Organization’s Global Research Roadmap for Covid-19 helped guide this effort, ensuring that resources were channelled to the areas where knowledge and innovation were most needed.

Research is no less important in the fight against cholera. That is why, last year, the Global Task Force on Cholera Control launched the Cholera Roadmap Research Agenda. Representing the collective vision of 177 global cholera experts and other stakeholders, the agenda identifies the highest-priority research questions. Getting the answers is essential to achieving the goals set out in the GTFCC’s Ending Cholera by 2030 global roadmap.

Many of the questions could just as easily be found in a Covid-19 research agenda. For example, what is the fastest, most cost-effective way to deliver a limited supply of vaccines? How can we enhance the uptake and sustainability of response measures to prevent the disease from reaching epidemic- or pandemic-level proportions? How do we engage meaningfully with at-risk communities in designing and implementing interventions? Which disease surveillance systems are the most effective, and when and where should they be deployed?

The questions may be the same, but the effort devoted to answering them has been very different. With Covid-19, strong political will and massive investment enabled researchers to produce answers quickly. Though cholera has been around much longer, solutions remain elusive. A key reason is that, whereas Covid-19 ravaged developed and developing countries alike, cholera was eradicated from the Global North more than 150 years ago. It is much harder to mobilise resources to tackle a disease affecting the world’s poorest and most marginalised people.

With just a fraction of the commitment underpinning the fight against Covid-19, lifesaving progress could be made in cholera research. Epidemiological surveillance would enable the mapping of transmission patterns. New and innovative diagnostic tests could increase the speed, efficiency, and quality of detecting and confirming cases. And new or improved vaccines would strengthen the connection between emergency response and long-term control and prevention.

Optimising the timing and dosage of vaccines is essential, as is learning how to engage communities to ensure that the needs of marginalised populations are addressed. Transforming treatment for vulnerable communities requires studying the impact of antibiotics on cholera transmission, and understanding what enables—and blocks—integration of cholera treatment into case management by community health workers.

Equipped with this knowledge, countries and health partners would be better positioned to choose the most effective tools and approaches as they pursue their National Cholera Plans. This, in turn, would make it easier to attract additional funding, which would drive further progress.

We have learned so much during the Covid-19 pandemic. We have listened to our public-health officials and taken steps to limit the spread of the virus: wearing face masks, practising social distancing, quarantining, getting vaccinated, and washing our hands more regularly. We must leverage this increased awareness and momentum to make further public-health gains, not just in our own communities, but worldwide.

That means taking aim at other, much older scourges. We have the tools we need to defeat cholera, but we must still do the research that is required to identify how, when, and where to use them. Only then can we protect the world’s most vulnerable populations from this all-too-precedented disease.

Qadri is Senior Scientist and Head of the Mucosal Immunology and Vaccinology Unit at the International Centre for Diarrhoeal Disease Research in Dhaka. Islam is Deputy Project Coordinator in the Mucosal Immunology and Vaccinology Unit at the International Centre for Diarrhoeal Disease Research in Dhaka.

—Project Syndicate