GLOBAL HEALTH & DEVELOPMENT

editor's note

The headlines of a few years ago are back.

Did the pandemic originate because of a lab leak in Wuhan or was it a spillover from an animal at the Wuhan wet market (pictured above)?

Many scientists in the virology community share the view that the virus would have found its way from an animal into its first human host and then spread at that point from human to human -- a "spillover" from animals to people.

But the debate resurfaced this week when Senator Rand Paul released pandemic diaries kept by Dr. Anthony Fauci, the former director of the National Institute of Allergy and Infectious Diseases.

Fauci has asserted that the scientific evidence points to a spillover.

Paul and other political figures as well as some scientists have advocated for an alternative explanation, asserting that the possibility that the virus was engineered in a lab should not be discounted. 

NPR has extensively covered this debate. This week, we look at what the evidence shows -- and why, even though there is not 100% certainty, the World Health Organization issued a statement in 2025 that ""the weight of available evidence … suggests zoonotic spillover … either directly from bats or through an intermediate host."

Read the story here.

Marc Silver,
Editor, global health