The mystery surfaced early in the pandemic. Hospitals were jammed with coronavirus victims, but the official death count in Mexico City appeared suspiciously low. Sitting at her dining-room table one afternoon, Laurianne Despeghel, a 31-year-old economic consultant, clicked from chart to chart on her laptop, puzzling over how to uncover the real toll. “I think the data exist,” she typed to Mario Romero Zavala, a fellow math geek. She’d heard that death certificates were stored in a database at the city’s civil registry. But it would be tough to crack. A day later, Romero Zavala messaged back with an idea. “I’m going to hurry,” the 37-year-old software developer wrote. “I think by tomorrow morning we’ll have the data.”

“WOW!!!” Despeghel typed.

Thus began a cat-and-mouse game with the government that would last nearly a year and catapult the pair to national prominence. Just days after their conversation, they’d conclude that around 8,000 more people had died in Mexico’s capital in the first five months of 2020 compared to prior years. By February 2021, they’d count 83,235 excess deaths — more than twice the government’s confirmed covid-19 fatality total.
The only two hospitals in Southern California’s rural Imperial County were forced to close their doors to new coronavirus patients on May 19. (Reuters)

Around the world, citizen sleuths have been scrambling to discover the pandemic’s true toll. As fatalities have soared, they’ve upstaged governments that have been slow or unwilling to report the scale of the tragedy.

Even developed democratic countries have struggled to keep pace with covid-19 fatalities. The challenges range from a lack of testing to incorrect diagnoses to slow-moving death registry systems. To get the best sense of the pandemic’s toll, scientists are turning to excess mortality, the difference in overall fatalities compared to prior years. It includes people killed by covid-19 and indirect victims — for example, patients unable to get treatment for other problems at overwhelmed hospitals.

In Mexico, calculating the fatalities has been particularly fraught. The pandemic response has been led by highly trained scientists, including Mexico City’s leftist mayor, Claudia Sheinbaum, who has a PhD in energy engineering. They’ve produced detailed mortality reports, but released them well after the fact, while announcing far-lower daily totals of confirmed covid-19 deaths. That’s led to suspicions the government is masking the size of the disaster.