AAAS Kavli Lecture: Megan Molteni on What To Do When Experts Are Getting It Wrong

Emily Hughes
Thursday, October 20, 2022

During the early months of 2020, the COVID-19 pandemic posed a significant challenge for scientists and science journalists, STAT science writer Megan Molteni said in a lecture at the University of Montana on Oct. 12. Molteni called the outbreak of a novel infectious disease “a crisis of information” that forced journalists to choose what to write about and how to frame their narratives.

Molteni’s talk was the first of this year’s three AAAS Kavli Science Journalism Award lectures. The annual series brings winners of the distinguished award to campuses for public lectures and workshops with journalism students.

Megan Molteni | Courtesy of Megan Molteni

Molteni, who won a Magazine Gold Award in 2021, emphasized the importance of journalistic scrutiny in the face of uncertainty, particularly when the accepted science seems to disagree with events being observed on the ground. “As science journalists,” Molteni said, “it’s our job to interrogate science as a human endeavor that it is a product of history and a constant work in progress.”

She shared several “high stakes” instances early during the COVID-19 pandemic during which both scientists and journalists were forced to grapple with uncertainty. Asymptomatic spread – transmission of COVID by apparently healthy individuals who already had contracted the disease – was one of the earliest stumbling blocks for scientists, journalists and public health officials, Molteni said. Anecdotal case studies of asymptomatic spread occurred long before scientists had a full understanding of the illness caused by SARS-CoV-2.

Molteni, who was reporting for WIRED at the time, said she had to consider whether these early instances of asymptomatic spread were worth considering – if they were “truly edge cases” or “harbingers of what's to come.” She noted moments where policy lagged behind the science, citing World Health Organization officials who called asymptomatic spread “very very rare.”

At the time, Molteni said, she and her team at WIRED took their lead from the WHO and public policy leaders like National Institute of Allergy and Infectious Diseases director Anthony Fauci, who emphasized that epidemics have historically been driven overwhelmingly by symptomatic spread. Molteni decided to hold off on giving weight to case studies of asymptomatic spread until scientists had a clearer understanding of what was going on.

But her “wait and see and synthesize” strategy was tested a few months later when droplet versus aerosol spread came to the forefront of the COVID-19 conversation. Droplets are larger particles, noted Molteni, that only spread through coughing and sneezing associated with symptomatic cases. This didn’t account for asymptomatic spread, so a growing scientific consensus suggested that COVID-19 was transmitted through smaller aerosol particles, which can be spread simply through breathing and hang around in the air much longer than droplets.

Meanwhile, the WHO had not changed its guidelines or website language to reflect the growing body of data supporting aerosol spread transmission. This led to guidelines centered around hand washing and social distancing, rather than guidelines that emphasized mask use and air filtration. “In the world of healthcare,” said Molteni, “the distinction between droplet and airborne transmission has enormous consequences.” The stakes were high.

WHO headquarters in Switzerland | Shutterstock

Molteni noticed that the heart of the debate was a narrow distinction that defined droplets as larger than 5 microns, and aerosol spread under that measurement. “I'd never heard of the five micron distinction before,” said Molteni, “but once I started paying attention, I noticed it everywhere, especially on Twitter” where aerosol scientists were sharing and discussing new studies and case reports that supported the idea that airborne transmission was driving the pandemic.

In her reporting, Molteni reached out to Virginia Tech aerosol scientist Linsey Marr. Marr had been convinced of airborne transmission since the middle of March, and had joined with 35 colleagues to warn the WHO. Their concerns were pushed aside, said Molteni. So Marr signed her name along with 238 scientists to a letter calling out the WHO's missteps and urging them to revise their recommendations. Molteni and her colleague Adam Rogers broke the story for WIRED, which was covered by the New York Times shortly following.

“But even as this was happening,” said Molteni, “I was thinking about something else that Marr had told me that seemed like maybe an even bigger story.” Marr had a hunch that they were unable to break through to the WHO advisors because they were “operating under a false idea about how aerosols and droplets behaved.” That idea, Marr suspected, was rooted in an outdated 5 micron definition that had its origins somewhere back through the decades. Someone had gotten that size wrong, Marr said. 

Molteni asked if she could follow along as Marr and her team investigated the origins of the 5 micron definition. They found that the WHO’s initial guidance was based on a misinformed definition of aerosols which specified that all infectious particles smaller than 5 microns are aerosol spread, while anything larger than 5 microns is a droplet. But, in fact, particles much larger than 5 microns can stay afloat and behave like aerosols.

It took another year for the WHO to update its website to match Marr’s research. Molteni said she pursued this story not to create heroes and villains around the issue. “In reality,” she said, “it was about a lot of people wading through a lot of uncertainty, all trying to do their best with the information they had at the time, while lacking a common language to effectively put the respective pieces of the puzzle together.”

Molteni came to see that risk-averse health authorities don’t change their recommendations overnight and that they require clear evidence to support policy changes. But that evidence can be hard to nail down when confronted by a novel virus with a wide range of effects. Molteni noted that scientists now estimate that one-third to one-half of those affected by the COVID-19 never experience symptoms.

Health authorities have “an incredibly difficult job to do,” Molteni said, as do the science journalists trying to sort through conflicting research findings. They must be clear about how science generates knowledge and what some of the limitations are, including a tendency by various disciplines to squirrel away data in their own research silos.

For science journalists, she said, “our job is to make it as accessible as possible.”

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