On Jan. 30, 2020, the World Health Organization sounded the alarm about an unfamiliar and deadly new virus, declaring it a global health emergency.

"Over the past few weeks, we have witnessed the emergence of a previously unknown pathogen, which has escalated into an unprecedented outbreak," WHO Director-General Tedros Adhanom Ghebreyesus told reporters.

Tedros was talking about what would later be named SARS-CoV-2, the coronavirus that causes the disease now known as COVID-19, which is all too familiar today. As of Jan. 25, 2023, almost 700 million people have had confirmed infections with the coronavirus that causes COVID-19, and nearly 7 million people have died.

Science is about making decisions and changing course as more evidence rolls in, and the COVID-19 pandemic has been a case of science playing out on a global stage. Here are excerpts from NPR's coverage around the time of that WHO announcement in January 2020. They show that health officials, scientists and NPR's reporters worked to bring the most accurate information available to people — but also show how much we had to learn.

Jan. 22: "Highly infectious"

Back in early 2020, even the experts were still figuring out what to expect from the novel coronavirus first reported in Wuhan, China. The government of Hubei province, where Wuhan is located, confirmed hundreds of infections and 17 deaths. NPR reported that Chinese authorities were concerned that the busy Lunar New Year travel season would spread the disease, so travel restrictions were put in place.

The Chinese Center for Disease Control and Prevention "said that while the virus does not appear to be as virulent as the one that caused a SARS — severe acute respiratory syndrome — pandemic 17 years ago, it is nonetheless 'highly infectious,'" NPR reported.

Jan. 23: "High risk" regionally and globally

By late January, Australia, France, Japan, Singapore, South Korea, Taiwan, Thailand, the U.S. and Vietnam had reported fewer than five cases each of the new coronavirus. Tedros, the WHO's chief, told reporters that the outbreak represented a "high risk" regionally and globally and an emergency in China, as the country was rushing to set up quarantine and treatment facilities. "But," he said, "it has not yet become a global health emergency."

Jan. 25: COVID-19 would be a "tiny little blip"

In a story that addressed the question of "how worried" people outside China should be, William Schaffner, a professor in the Division of Infectious Diseases at Vanderbilt University Medical Center, predicted that based on the data available at the time, the novel coronavirus would be "a tiny little blip on the horizon" compared with annual flu cases.

Jan. 28: "WHO's highest priority"

As confirmed cases in China doubled in a matter of days, public health officials around the world took action. Countries tightened restrictions on travel from China. In Hong Kong, where eight cases were confirmed, authorities closed museums, libraries and sports centers and urged people to work from home to slow person-to-person transmission — a preview of what would happen in the U.S. in March. "Stopping the spread of this virus both in China and globally is WHO's highest priority," Tedros said at a meeting with Chinese President Xi Jinping.

Jan. 29: Masks — "If they did wear it, yes, they got protection"

Cities in China and other parts of Asia adopted masks in January and reported shortages of masks as case counts rose. Even though the position of U.S. officials in late January was that wearing masks was not necessary for members of the general public, NPR coverage pointed out that even inexpensive, disposable surgical masks could offer some, though not perfect, protection against disease if people wore the masks "all the time when you are in the same room as the infected person," as one infectious disease researcher put it. "If they did wear it, yes, they got protection," the researcher said, referring to a study that tested the efficacy of surgical masks.

Jan. 30: A global health emergency "because of what is happening in other countries"

By the day the WHO declared a global health emergency, person-to-person transmission of the coronavirus had been reported in China, Germany, Japan and Vietnam. The virus had spread to at least 20 countries. "The main reason for this declaration is not because of what is happening in China but because of what is happening in other countries," Tedros told reporters. Yet it wasn't a foregone conclusion that a pandemic was looming. In 2020, the prior three global emergencies declared by the WHO were for Zika and two separate Ebola outbreaks. Those illnesses did not end up affecting enough people worldwide to become pandemics. COVID-19 did. It soon went from an emergency to a pandemic declared by the WHO on March 11, 2020.

Jan. 30: "Risk to the American public is low"

On the same day as the WHO's January declaration, U.S. authorities announced the first case of person-to-person transmission of COVID-19 in the United States. "Health officials say it is not cause for alarm," NPR reported. It was the sixth known case in the U.S. at that time, compared with nearly 9,700 confirmed cases in China.

Overall, "the immediate risk to the American public is low," said Robert Redfield, then the director of the Centers for Disease Control and Prevention, at a press briefing.

In January 2020, NPR also reported that "scientists are trying to figure out if the disease can be spread before people are coughing or showing other symptoms." Just a few months later, in April 2020, scientists learned that the coronavirus could indeed spread silently from people who showed no symptoms.

Jan. 31: "Probably mutated from a coronavirus common in animals and jumped over to humans"

Reports that the first people sickened with the coronavirus all had connections to a sprawling complex of stalls that sold wild animals, meat and live fish drew attention to wet markets. "Researchers believe the new virus probably mutated from a coronavirus common in animals and jumped over to humans in the Wuhan bazaar," NPR reported. The origins of the COVID-19 pandemic later became contentious, with some experts, including WHO chief Tedros, saying that the possibility that the virus escaped a Wuhan laboratory was dismissed too early. But the lab leak theory has not gained widespread support. In fact, just this week, 150 virologists signed a commentary stating that all the evidence so far suggests the pandemic started naturally.

Multiple dates in January: "Wuhan coronavirus"

The pandemic had social ramifications in addition to scientific ones. In 2015, the WHO issued guidelines for creating non-stigmatizing names for new diseases. Some of NPR's January 2020 headlines refer to the "Wuhan coronavirus" — problematic because the shorthand was strictly based on the virus's origin. The official disease name COVID-19 (COronaVIrus Disease from 2019) debuted on Feb. 11, 2020.

The pandemic triggered a global wave of violence and hate against people of Asian descent. In a March 2021 NPR story, Yulin Hswen, an assistant professor of epidemiology and biostatistics at the University of California, San Francisco, said officials could have done better. "Public health people know there is a history of racializing diseases and targeting particular groups," said Hswen. "They could have done more to defend the Asian community."

Feb. 2: "Testing ... must be done at the CDC in Atlanta"

COVID-19 spread silently in large part because countries' capacity to detect new cases was limited in January 2020. "As it is now, testing for coronavirus [in the U.S.] must be done at the CDC in Atlanta," NPR reported on Feb. 2, 2020. "A diagnostic test that could be done in local doctors' offices or even at home would make a big difference in managing the epidemic." Today, people in the U.S. and around the world debate whether to take at-home rapid tests once, twice or more — and worry about false negatives.

Carmen Drahl (@carmendrahl) is a freelance science writer and editor based in Washington, D.C.