The World Health Organization (WHO) officially characterized COVID-19 as a pandemic on March 11, 2020, after the virus had spread to 114 countries, infected more than 118,000 people, and killed 4,291. That declaration came roughly six weeks after WHO had already classified the outbreak as a Public Health Emergency of International Concern (PHEIC) on January 31, 2020. The emergency designation remained in place for over three years before being lifted on May 5, 2023.
The Two Key Declarations
WHO’s response unfolded in two distinct stages. The first was the PHEIC declaration on January 31, 2020, which is the highest alarm the organization can sound under international law. A PHEIC signals that an outbreak poses a risk beyond the country where it started and calls for a coordinated global response. At that point, the virus was still largely concentrated in China, but cases were appearing in other countries.
The second, more widely remembered moment came on March 11, 2020, when WHO Director-General Tedros Adhanom Ghebreyesus used the word “pandemic” for the first time. Calling something a pandemic is not a formal legal category under WHO’s rules. It carries no new powers or obligations. But it sent a powerful political signal: this was no longer a regional crisis. Governments around the world began implementing lockdowns, travel restrictions, and emergency measures in the days that followed.
How WHO Tracked the Virus as It Evolved
As SARS-CoV-2 mutated, WHO developed a classification system to flag the most dangerous new forms of the virus. Starting in late 2020, variants that posed increased risk were sorted into two categories: Variants of Interest and Variants of Concern. The latter designation, applied to strains like Alpha, Delta, and Omicron, indicated higher transmissibility, more severe disease, or reduced effectiveness of vaccines and treatments.
Before May 2021, these variants were known mainly by their scientific lineage codes, which were confusing and easy to mix up. WHO then introduced Greek-letter labels to give the public and media simple, neutral names that didn’t stigmatize any country. In March 2023, the tracking system was updated again to reflect the virus’s shift from acute emergency to an ongoing, slower-evolving threat.
Guidance That Shifted Over Time
WHO’s public health advice evolved as understanding of the virus deepened, sometimes controversially. Early guidance focused on hand hygiene and droplet precautions, reflecting initial assumptions that the virus spread primarily through large respiratory droplets landing on surfaces or being inhaled at close range. The organization was slower to acknowledge that smaller airborne particles (aerosols) could transmit the virus across indoor spaces, even without close contact. This delay drew sharp criticism from aerosol scientists worldwide.
Mask guidance also shifted. WHO initially reserved mask recommendations for healthcare workers and symptomatic individuals. As evidence grew that people without symptoms could spread the virus, the organization began encouraging fabric face masks in public settings where physical distancing wasn’t possible. Indoor ventilation eventually became a core pillar of WHO’s prevention advice, alongside vaccination and respiratory hygiene.
The Search for the Virus’s Origin
In early 2021, a joint WHO-China study team investigated how the virus first reached humans. Their report concluded that SARS-CoV-2 most likely originated in bats and spread to people through an unidentified intermediary animal. A laboratory leak was ranked as “extremely unlikely.” The team also found evidence suggesting the virus may have been circulating in China as early as mid-to-late November 2019, weeks before the first official reports.
The investigation was immediately contentious. Critics argued the team had insufficient access to raw data and that Chinese authorities constrained the scope of the inquiry. WHO itself later acknowledged the need for deeper investigation, and the lab-leak hypothesis has continued to be debated in scientific and political circles. No definitive answer has been reached.
Vaccines and the COVAX Initiative
WHO played a central role in evaluating COVID-19 vaccines through its Emergency Use Listing process, which allowed countries without their own regulatory agencies to rely on WHO’s safety and efficacy assessments. Multiple vaccine types received this listing, from mRNA-based shots to traditional protein-based formulations produced by manufacturers across several countries.
To address the enormous gap between wealthy and lower-income nations, WHO co-led COVAX alongside Gavi (the Vaccine Alliance), CEPI, and UNICEF. Launched in 2020, COVAX aimed to ensure that vaccines reached every country, not just those that could afford to buy them first. By the time the initiative closed on December 31, 2023, it had delivered nearly 2 billion vaccine doses to 146 countries and prevented an estimated 2.7 million deaths in lower-income participating nations. While those numbers are significant, COVAX consistently fell short of its early targets, and many poorer countries received doses months or even a year after wealthier nations had begun vaccinating their populations.
The True Death Toll
Official COVID-19 death counts dramatically understated the pandemic’s actual impact. By the end of 2021, countries had reported roughly 5.42 million COVID-19 deaths. But a WHO-commissioned analysis published in Nature estimated that the real figure was closer to 14.83 million excess deaths globally during 2020 and 2021 alone. That’s 2.74 times the reported number. Excess deaths capture not only undiagnosed or unreported COVID-19 cases but also people who died because overwhelmed health systems couldn’t treat other conditions like heart attacks, cancer, or complications during childbirth.
Ending the Emergency
On May 5, 2023, WHO’s Director-General officially ended the PHEIC designation for COVID-19. The decision followed the recommendation of the International Health Regulations Emergency Committee, which met for the fifteenth time to evaluate the situation. The committee weighed three criteria: whether COVID-19 still constituted an extraordinary event, whether it posed a public health risk through international spread, and whether it still required a coordinated international response.
The conclusion was not that the virus had disappeared. SARS-CoV-2 continues to circulate and evolve. Rather, the committee pointed to declining death rates, falling hospitalizations and ICU admissions, and high levels of population immunity from both vaccination and prior infection. The virus, they determined, was no longer “unusual or unexpected.” It had become an established, ongoing health issue, more like seasonal influenza in its pattern, even if still more dangerous for vulnerable groups.
Reforms and the Pandemic Agreement
The pandemic exposed serious weaknesses in the international system for detecting and responding to outbreaks. Expert reviews found that many countries had fragmented authority over health emergencies, limited legal mandates, and poor coordination between government sectors. In response, the World Health Assembly approved amendments to the International Health Regulations in June 2024. These amendments, taking effect on September 19, 2025, require each country to designate a national authority with sufficient seniority and resources to coordinate its obligations under the regulations.
More ambitiously, the World Health Assembly adopted the WHO Pandemic Agreement on May 20, 2025. This framework covers disease surveillance, health system strengthening, research coordination, local manufacturing capacity, and sustainable financing. A central element is the Pathogen Access and Benefit-Sharing System, designed so that when a country shares a dangerous new pathogen with the global research community, it also receives fair access to the vaccines, treatments, and diagnostics that result.
The agreement also establishes a global supply chain network coordinated by WHO to distribute pandemic-related health products more equitably than occurred during COVID-19. It will enter into force 30 days after 60 countries ratify it through their own constitutional processes. Notably, the agreement explicitly states that it does not give WHO authority to impose lockdowns, vaccine mandates, or any other measures on any country.