The basis of the whole CTR model was collaboration, and it was built on doctor-to-doctor contacts. It paired Western scientific partners directly with local scientists to help them develop new diagnostic tests, or vaccines, or disease treatments. It prioritized working with younger scientists willing to train in the U.S. and then return to their home laboratories. It used American labs to confirm the work being done overseas, and small grants from American agencies to seed larger local investments.

This trust-building model proved extremely effective in dealing with very sensitive, and potentially very dangerous, biological programs. Examples of early collaborations include Ebola and HIV vaccine projects at a former biological weapon laboratory in Siberia, and a program to find new treatments for antibiotic-resistant bacteria at Obolensk, a lab near Moscow where weapons scientists had previously engineered anthrax to be antibiotic-resistant. These programs could have clear payoffs in the host country: In 2003, the same Obolensk team that made anthrax resistant to antibiotics in the 1990s worked with CTR to open Russia's first insulin production facility. One partnership, the Russian Flu Surveillance program, was a triple success: It gave the U.S. critical flu surveillance in a denied area, reduced the probability of laboratory escape by centralizing dangerous flu work, and offered a local payoff by giving animal producers better diagnostic tests for veterinary diseases. (It was also featured in a Discovery documentary, Flu Time Bomb.)

Transforming biocontainment facilities into public health labs, or biotech companies, wasn't always easy or smooth. U.S. scientists traveling in Russia were harassed by the FSB, always received the same hotel room and were required to receive Russian vaccines in order to work in Russian laboratories. Laboratories had their own dangers; a virus lab had already been suspected as the cause of one pandemic: In 1977 a flu outbreak appeared in northern China and swept the globe, killing more than 700,000 people, very likely stemming from an escaped virus from the 1950s that had existed only in laboratory freezers for two decades.

But payoffs have come both from partnerships and new on-the-ground knowledge. One key finding from CTR work, over the years, may be directly relevant to the Covid outbreak: In many cases, infections attributed to biocontainment laboratory activities actually occurred outside the lab, often during field collection of viral samples. Squirming, clawed and toothy animals bite and scratch during collection of body fluids. Teeth and talons easily penetrate the thin gloves required to maintain dexterity when handling fragile wildlife. And overhead, angry bats release a fine patina of virus-laden urine aerosols. As part of CTR field surveillance programs, I have collected viruses from Asian bats carrying coronaviruses, and from birds infected with bird flu, and can attest that the margins for personal protection during these expeditions are razor thin. The fact that researchers are not infected every time they do a field collection is a question that continues to stump us.

In cases like this, the actual point when infection occurred in the field can go unnoticed. In two Asian cases, for instance, "lab-acquired infections" among researchers were actually acquired during field collection, but symptoms were delayed for 2 and 3 days, after the researchers had returned to their home city and gone back to work in the lab. And there are other human factors at work: In China, if a researcher develops symptoms and suspects lab infection, they are inclined to hide the mistake from their superiors.

In the case of the Covid origins investigation, the timing of Wuhan Institute of Virology field collection trips, which we know occurred several times during 2019, need to be carefully tracked to pinpoint opportunities for more intensive clinical investigation. As of now, we simply don't have enough information to know whether these might have been connected to the pandemic outbreak -- and China has told its researchers not to share any data on field collection with WHO. But this scenario suggests a new target for research into Covid's origins: Focus on hospital lab data from anyone who came in contact with the Wuhan field virologists up to 4 weeks following their return from field collections.