Evidence increasingly suggests that infections play a critical role in triggering or exacerbating many chronic diseases—diabetes, multiple sclerosis, neurodegenerative diseases and even cardiovascular disease. Understanding the immune system’s responses to infections may unlock answers to many chronic diseases that medicine has treated as purely metabolic or neurological.

For example, a large-scale study in Nature this month found that the shingles vaccine reduced the risk of developing dementia by 20%, suggesting that varicella zoster virus reactivation plays a critical role in neurodegenerative diseases. Or consider a 2022 study published in the journal Science involving more than 10 million U.S. military personnel, which found that of 801 multiple-sclerosis cases, all but one were Epstein-Barr-positive before disease onset. This suggests Epstein-Barr infection is a prerequisite for MS development.

A century ago, recognition of cardiovascular risk factors—hypertension, smoking, high cholesterol—sparked a public-health revolution. It led to highly effective treatments and marked improvements in cardiovascular outcomes. Millions of people’s quality and length of life improved.

We are on similar ground now with chronic disease. Viral persistence, immune dysfunction, autoimmunity, latent virus reactivation and autonomic dysregulation have emerged as key contributors to long Covid, and these mechanisms are also found across various other postinfection illnesses. Advanced tools—such as molecular profiling and AI-assisted diagnostics—are helping scientists translate these insights into targeted therapies.

To make this revolution a reality, the U.S. needs a comprehensive national initiative to map, model and mitigate postinfection syndromes as well as tackle chronic diseases by addressing their infectious root causes. Ideally, Congress would provide additional funding and direction through legislation like the Long Covid Moonshot Act, introduced in the Senate last year. The Trump administration could also take immediate steps—streamline approval for new treatments, provide sustained research grants, create dedicated centers of excellence, and coordinate global efforts on diagnostics and therapies.

Advancing this research is one of the most effective ways to improve the lives of the tens of millions of Americans with chronic diseases.

Ms. Iwasaki is an immunology professor and Dr. Krumholz a cardiologist at Yale School of Medicine.