On COVID’s Fifth Anniversary, Scientists Reflect on Mistakes and Successes

Five years ago next Tuesday, the World Health Organization declared a global pandemic involving a dangerous new virus—and across the planet, life as we knew it ground to a shuddering halt. But the COVID emergency started well before that. Rewind to late December 2019: hospitals in Wuhan, China, were filling up with cases of a mysterious pneumonia. By January 2020, as the body count started to mount and Wuhan was locked down, other countries began reporting cases. The virus spread like an invisible airborne poison through a cruise ship quarantined off the coast of Japan. Italy became a hotspot of infection. One by one, countries and U.S. states issued stay-at-home orders, and major cities went eerily quiet. Within weeks, New York City hospitals filled up with desperately ill people. The dead piled up so quickly that refrigerated trucks were used as temporary morgues.

Today these events may feel like a distant nightmare for many people. This is not the case for those who lost loved ones or for health care workers who treated people when hospitals were overwhelmed. They will never forget. Still, by most measures, COVID feels nowhere near the dire threat it was in those first few years. People in the U.S. are not being hospitalized and dying of the illness at anywhere close to the rates that occurred in previous years. Experts have varying definitions of what it means for a virus to become endemic, but they agree that the COVID-causing virus SARS-CoV-2 is closer to that state now than it was in the past several years.

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“It is not at the level of an emergency that it once was,” says Jennifer Nuzzo, a professor of epidemiology and director of the Pandemic Center at the Brown University School of Public Health. But she cautions against making assurances. “We’re still not very good at predicting what COVID-19 is going to do,” Nuzzo says.

A Disease That Is Milder but Not Gone

Experts agree that the biggest reason COVID is now causing less death and severe disease is a high level of immunity to SARS-CoV-2. Most of the world’s people have had the disease or been vaccinated against it, or both. Studies estimate the COVID vaccines have saved millions of lives. And in contrast with early 2020, effective treatments—antivirals, including Paxlovid, and common steroid drugs—are now available.

“This winter there’s been a lot of respiratory disease, but relatively little of it has been COVID. And there’s been a continuing trend downward in terms of the total amounts of severe illness and death,” says William Hanage, an associate professor of epidemiology at the Harvard T. H. Chan School of Public Health. Scientists don’t know whether that downward trend will continue, though. “COVID is with us for the long run, as it always was going to be,” Hanage says. “It’s been getting better, but it’s still worth trying to make sure that you don’t transmit it to people who are vulnerable.”

Nevertheless, COVID continues to kill more people than influenza—although the flu has hospitalized more people in the U.S. this winter. And SARS-CoV-2 still triggers localized waves of infection several times a year, wastewater testing reveals. More than seven million people worldwide have died of COVID, though this is likely a gross underestimate. And the virus continues to kill thousands of people every month.

“It’s been a pretty difficult five years for everyone, for the whole world,” says Maria Van Kerkhove, technical lead for COVID response at the World Health Organization. “I think the whole world wants to forget that it happened and move on, which is completely understandable, because we’ve gone through something that has been tremendously difficult,” she says. But “I think we need to make it very clear that COVID is not gone.”

Millions of people had or suffer from long COVID—a catchall phrase describing postviral symptoms that range from mild to debilitating. Scientists have begun studying the causes of long COVID. Evidence suggests vaccines reduce the risk of developing the condition, but treatments remain elusive.

With the worst of COVID seemingly in the rear-view mirror, however, we can finally take stock of what happened and try to make sense of the U.S.’s response.

Successes, Failures and Hard-Earned Lessons

In the early days of the pandemic, scientists and public health experts had to react in real time to a brand-new pathogen—and mistakes were certainly made. U.S. officials botched the initial COVID testing strategy, for example. At first, all tests had to be run through the Centers for Disease Control and Prevention, which created a serious bottleneck. Exacerbating this, the CDC’s test itself turned out to be flawed, making results inconclusive. In future pandemics, testing should be made available much more quickly and widely via the private sector, experts say.

Additionally, public health officials both at the WHO and in the U.S. government were slow to acknowledge that SARS-CoV-2 could spread through tiny airborne particles, or aerosols. Some experts actively warned the public not to wear face masks, arguing either that they were ineffective or that health care providers needed them and should be prioritized amid the initially short supply.

“I think the challenge was the use, specifically, of that word ‘airborne,’ which did have a technical meaning. It took three years to change the terminology related to airborne transmission, and we now say ‘through the air,’” Van Kerkhove says. But she pushes back on the narrative that the WHO didn’t acknowledge the virus’s potential to spread this way. “We had always recommended airborne precautions. In the beginning, it was particular settings, and it was related to health care workers. But then that expanded to other settings” such as gyms and churches, she says. Still, she acknowledges that the messaging could have been clearer.

In those first few days and weeks of uncertainty, as terrifying news about the virus emerged from around the world, by and large, Americans—with some exceptions—initially banded together against a common threat. Gatherings were limited or canceled. Those who could do so stayed home from work or school to help “flatten the curve” of transmission. The goal was to slow the numbers of people getting infected with COVID and becoming severely ill to avoid burdening already overwhelmed hospitals. And in fact, research showed that flattening the curve actually worked. The problem, experts say, is that there was no exit strategy.

“The whole idea of flattening the curve was like a pause button: measures you could employ to buy time to prevent hospitals from becoming overwhelmed, such that you could protect them for six months” or until we had a vaccine, Nuzzo says. But there was no clear end point. “We didn’t have the next phase lined up.”

Hanage agrees that the U.S. could have been smarter with stay-at-home orders. “I also think that we really missed an opportunity in, roughly, the summer of 2020, because by that point in the United States, the initial surges had sort of been brought under control,” he says.

Perhaps no aspect of the U.S. pandemic response has been as fiercely debated as school closures. “The issue of schools and disease is such a political third rail right now that nobody wants to even talk about what, if anything, we should do to protect kids in schools,” says Nuzzo, who wrote a March 2020 op-ed arguing against closing schools.

These closures made some sense in the pandemic’s earliest days and weeks, when the virus’s impacts were still unknown and we lacked even basic treatments, let alone vaccines. Yet many people expressed outrage at how long they went on—or questioned whether they were necessary at all. Some argued that the virus caused milder infections in children; this was generally true, though not in all cases. But protecting kids was not the only point of closing schools; it was also meant to stop chains of transmission to vulnerable adults such as teachers, staff and adult family members.

As time wore on, however, the mental health and social costs of keeping kids home and doing online schooling began to mount. Lengthy, blanket closures could have been replaced by more sustainable interventions such as masking and improving air quality through better ventilation systems.

“I think what really was unfortunate is that the messaging from public health often wasn’t clear, or it was much more definitive than it should have been,” says Michael Osterholm, chair of public health and director of the Center for Infectious Disease Research and Policy at the University of Minnesota. “Then something happened that negated what we previously said, and it made people challenge how honest we were being—when, in fact, it was never about dishonesty. It was about trying to communicate uncertainty, and that was a real problem.”

Despite these challenges, there were some undeniable triumphs in the scientific response to the pandemic. Within 11 months of the virus being genetically sequenced, the U.S. had developed two mRNA vaccines that prevented severe disease and death extremely effectively. These were the fastest vaccines ever made, says Paul Offit, an attending physician in the Division of Infectious Diseases at Children’s Hospital of Philadelphia. “To me, the hero of this pandemic is the National Institutes of Health,” whose scientists laid much of the groundwork for the remarkably effective mRNA vaccines, he says. “And then what the Trump administration did was Operation Warp Speed, an $11-billion commitment to basically bet on six horses to win one race, and that was an amazing production of funding.”

But “vaccines do absolutely nothing when they’re sitting there in a vial,” Hanage notes. “They actually need to be in arms.” Unfortunately, vaccines—like many aspects of the pandemic—became politicized amid a steady barrage of blatant lies and misinformation from President Donald Trump and many of his supporters, and a small but vocal part of the population refused to get them. In many areas, people who wore a mask were mocked or berated, and some were physically assaulted. As a result, people in Republican-dominated states and counties died at higher rates than people in Democratic-dominated ones.

The divide highlights just how polarizing the COVID response was. A recent Pew survey found that nearly three in four U.S. adults say the pandemic did more to drive the country apart than to bring it together. Americans have always been individualistic, and many people did not take kindly to being told to wear a mask or get vaccinated—even when such recommendations were aimed at protecting others. The concept of this kind of collective altruism is hard to communicate, and public health messaging often fell short.

“I think the worst possible situation that you can have, when you’re in the middle or the beginning of an evolving pandemic, is the profound degree of divisiveness that we have had and still have in our country,” said Anthony Fauci, the famous doctor and former head of the National Institute of Allergy and Infectious Diseases, in an interview with Scientific American last year. “It’s like being at war. The common enemy is the virus. And we were acting in many situations and in many respects as if the enemy were each other.”

Indeed, Fauci—widely celebrated as a hero and “America’s doctor” early in the pandemic—was ultimately vilified by Trump and many of his followers as the face of stay-at-home orders and other social restrictions. Masking and proof-of-vaccination requirements drew a strong backlash, and a few U.S. counties have since banned masking in public (with some exceptions). Some states have banned COVID vaccine mandates. Such bans may unfairly target disabled and immunocompromised people and could leave the entire population more vulnerable to future disease outbreaks.

Are We Prepared for Another Pandemic?

One thing is certain: the world will experience other pandemics, likely within our lifetime. The most likely culprit would be some type of influenza, as was the case in the 1918 pandemic.

In fact, the U.S. is already battling a steadily growing outbreak of H5N1 avian influenza, or bird flu, which has been infecting wild birds, poultry and, as of March 2024, dairy cattle. The virus is highly deadly to poultry, triggering massive culls that have driven up the price of eggs. Historically, H5N1 hasn’t been readily transmitted to humans. But in the few outbreaks that have occurred among people, it has had a staggering mortality rate of almost 50 percent. In the current outbreak affecting dairy cattle and poultry in the U.S., 70 human cases—most of them mild—and one death have been reported.

Experts have criticized the H5N1 response among federal and state health agencies, warning that testing has been insufficient and that infections are likely being missed. Dairy farms have been reluctant to test for the virus over worries about losing income, and farm workers—many of whom are undocumented—often fear losing their jobs or being deported if they seek medical care. The election of an intensely anti-immigrant president has only exacerbated these fears.

It’s far from certain that H5N1 will become a pandemic. The virus would need to mutate to a form that spreads easily between humans, which apparently hasn’t happened yet. But if and when we in the U.S. do face a pandemic, regardless of what causes it, in some ways we may now actually be worse equipped than we were when we faced COVID.

“Right now I think we’re less prepared for the next pandemic than we were in 2020,” Osterholm says. “One of the most important weapons we have in a fight against [a pandemic virus is trust in] public health recommendations. And I think that, at this point, that’s a huge issue for the public, in terms of not trusting vaccines.”

Current threats to the institution of science itself are exacerbating the problem. Trump has nominated some overtly antiscience and antivaccine people—most notably Secretary of Health and Human Services Robert F. Kennedy, Jr.—to lead federal health agencies. He has made sweeping cuts to the CDC, the NIH and other science agencies. And in one of Trump’s first executive orders, he announced plans to withdraw the U.S. from the WHO.

“You have a public health infrastructure that is falling apart,” Offit says. You have people that are heads of various agencies—like NIH or CDC or [Food and Drug Administration] and now [the Department of Health and Human Services]—that have disdain for those agencies, that don’t trust those agencies.”

Yet in other ways, we may be slightly better prepared, Nuzzo adds. “People have lived through a pandemic recently, and they remember it to some extent,” she says. Unlike what happened with COVID, if an influenza pandemic were to hit us, we would be able to use tests for the virus and some vaccines that we have already stockpiled. “People generally understand influenza disease. We’ve been studying H5 infections for 25 years, so we know a bit about the virus and how it affects the body,” Nuzzo says. “That said, there are going to be challenges.” [Editor’s Note: H5 is a subtype of bird flu that includes H5N1 and other viruses.]

The WHO’s Van Kerkhove agrees we are more ready in some ways and less so in others. “We are [better prepared] because we’ve all gone through this, and what we learned at the beginning of COVID was: countries that had the trauma and experience of these types of outbreaks—with SARS, with MERS, with avian influenza—were better prepared. They acted fast. They knew how bad it would be. And so now every country has that experience.”

But maintaining that level of preparedness is a challenge. “How do we keep up the momentum and the pressure on governments and organizations and institutions to make sure that we continue to invest in public health, we continue to invest in prevention? Prevention is a very hard sell,” Van Kerkhove says.

She hopes the U.S. will change its mind about working with the WHO and other countries. “I think it is in all member states’ best interest to work collectively together on pandemic preparedness, on surveillance, detection, risk assessment,” Van Kerkhove says, “because these pathogens don’t respect borders.”