5 COVID-19 Takeaways That Changed Medicine

This article appeared in the July/August 2021 issue of Discover magazine as “COVID Lessons.” Subscribe for more stories like these.

As the pandemic mound the world, killing thousands every day and turning us all into shutins, the entire health care system faced a trial by virus. The stakes were inhumanly high, but doctors, researchers and crisis planners stepped up, advancing the field of public health along the way. Here’s how the most important takeaways from COVID-19 are shoring up our collective defenses and preparing the medical world for the next rogue pathogen.

1. Masks Work. Really.

Fierce debate raged in the pandemic’s early months about whether wearing face masks curbed viral transmission. The confusion was understandable: In March 2020, the World Health Organization urged people not to wear a mask unless they were sick with COVID-19 or caring for someone who was ill.

Scores of health officials echoed the organization’s advice, with many now claiming that it was an effort to preserve masks for medical workers.

But this seeming consensus collapsed in the face of more than a dozen new studies showing that masks slowed the virus’ spread. There was never much science that said masks didn’t work, says Mark Roberts, director of the University of Pittsburgh’s Public Health Dynamics Laboratory. Pre-2020 research already showed masks’ effectiveness, and COVID-era studies cemented that verdict, setting the stage for more widespread, ongoing mask use.

It’s true that mask layers are porous enough that viral particles alone could pass through them. But most viruses, including COVID-19 and the flu, don’t hang out solo in the air. They’re surrounded by so-called respiratory droplets, globs of fluid that people spew when they cough or sneeze. Masks effectively block most of those larger droplets, both incoming and outgoing, from your mouth or nose.

“If both people in an encounter are wearing masks, the likelihood of transmission is substantially lower,” Roberts says.

Last year’s crop of studies emphasized just how much lower. One found that N95 masks — the most effective variety on the market — blocked 99 percent of a wearer’s cough droplets from escaping into the surrounding air. That translates into a much lower likelihood of transmission on the population level. Three weeks after authorities in 15 states plus Washington, D.C., announced mask mandates, another study reported, the virus’ daily growth rate in those states slowed by 2 percentage points, ultimately preventing more than 200,000 people from getting the virus.

The broader takeaway of this research is that masks can work for more than just preventing COVID-19. Flu case counts for the 2020–21 season were more than 90 percent lower than the prior year, in large part because people weren’t spewing droplets all over each other. Tom Frieden, former CDC director, recently proposed a new culture of wearing masks around others whenever you don’t feel well — a practice that’s been the norm in many Asian countries for years. If we’re smart, we’ll follow their lead.

2. Immune System Mapping

(Credit: Lenti Hill/Shutterstock)

Much of the havoc COVID-19 wreaks doesn’t come from the virus itself, but from your immune system’s response to it. This full-scale immune mobilization can unleash a torrent of symptoms, including airway inflammation and the dreaded “cytokine storm,” where your body’s immune cells attack your own tissues. By tracking this tempest from its earliest stages on a patient-by-patient basis, researchers can now predict what course the disease will take and what treatments might work best on a given case. This immune-centered strategy, refined during the pandemic, is poised to transform disease management.

As soon as the pandemic hit, immunologists worldwide began sampling COVID-19 patients’ blood in search of distinct signatures related to the disease. Their sampling yielded a set of immune biomarkers that contained important clues about patients’ prognosis.

Those with high levels of certain cytokines — small proteins that support communication between immune cells — proved more likely to develop severe disease in a King’s College London study. Patients with lower levels of these compounds were able to leave the hospital more quickly. In addition, high concentrations in the blood of certain natural antibodies meant COVID-19 patients were more likely to die or be intubated, according to a Massachusetts General Hospital study.

Results like these could usher in new hospital protocols where COVID-19 patients take a standard immune blood test upon hospital admission, says Adrian Hayday, an immunologist at King’s College London and the Francis Crick Institute. If a patient’s immune signature predicts quick symptom resolution, doctors could more confidently discharge them into home-based care. But if immune markers point to a more severe course, providers could concentrate efforts and expedite intensive therapies like monoclonal antibodies.

Tracking immune biomarkers could also allow bespoke treatment of other diseases, from influenza to cancer to novel coronaviruses. Many conditions have their own distinct immune signatures that may predict disease progression, letting doctors start appropriate treatment when the odds of success are higher. “If I can monitor the immune system and see it deviate from a status quo, we may be in a situation where we could get early warning signs,” Hayday says. “That’s how the future of immune profiling needs to look.”

3. Vaccine Production Speed

In early 2020, before most people had even heard of an N95 mask, scientists were working around the clock to develop a COVID-19 vaccine. Large-scale trials of several vaccines were underway by fall, and months later, providers were injecting them into arms by the millions. It was a vaccine development land-speed record for a virus that claimed hundreds of thousands of lives within months — especially considering that, pre-COVID, typical vaccine timelines ran closer to a decade.

There’s every reason to think we can pull off such feats in the future, says Sharon Nachman, a pediatric infectious disease specialist and director of the Office of Clinical Trials at Stony Brook University. The bottom line, in Nachman’s view, is that after COVID-19 popped up, the system worked exactly the way it was designed to. The medical infrastructure was ready (just like it was for the warp-speed H1N1 flu vaccine, which got less fanfare), and the players involved, from pharmaceutical companies to universities’ steering trials, stepped up and fulfilled their roles.

The messenger RNA (mRNA) technology that debuted in Pfizer and Moderna’s COVID-19 vaccines also bodes well for swift vaccine development. In simple terms, mRNA vaccines give the body’s cells instructions to mount strong defenses against a virus. By making new mRNA in the lab — a low-cost process — scientists can quickly create a vast library of such instructions, each tailored to a different pathogen. This finger-snap customization has experts calling mRNA a new “vaccine on demand” option.

A few caveats mar this rosy outlook, however. Because COVID-19 provokes a robust immune response, it was a good fit for mRNA vaccines that stimulate antibodies against the virus. Time will tell if it proves effective against wilier viruses like HIV, which lurk in hiding and evade antibodies. Moderna announced earlier this year it is working on two mRNA vaccines against HIV, slated for phase 1 trials this year.

Other fast-track vaccine tripwires are more practical than scientific. Having transformative science doesn’t necessarily mean we’ll use it — chances are, a virus affecting mostly poorer countries won’t spur the accelerated vaccine timeline we saw with COVID-19. And, as the U.S. learned anew this winter, while having vaccine doses on hand is one thing, getting them to recipients is a totally different challenge. “We don’t have a ready-made national emergency vaccine delivery system,” says former CDC director Tom Kenyon, now with the humanitarian relief organization Project HOPE. “We’re going to have to get that in place with the next pandemic.” Without such a distribution plan, future state-of-the-art vaccines can’t have the game-changing impact they were meant to produce.

4. Addressing Racial Disparity

(Credit: Seventyfour/Shutterstock)

It’s a reality the pandemic has brought into stark relief: Systemic racism is endemic in U.S. health care. COVID-19 has disproportionately hit communities of color — a June 2020 analysis by health professions found that in one region of Louisiana, 3 in 4 patients hospitalized for the virus were Black, even though only 1 in 3 residents of that region were Black. Infection and death rates have also been two to four times as high among Black, Latino and Asian peoples as among white people, according to an analysis of 300 hospitals in 21 states.

Behind these numbing statistics are the stories of thousands who might have been saved with better care. In one viral video, Susan Moore, a Black doctor with COVID-19, described how hospital doctors were dismissing her breathing problems. “This is how Black people get killed,” said Moore, who later died of COVID-19 complications. Tragedies like this, repeated around the country, underscore the need for radical change that long outlasts the pandemic.

Communities of color are in the virus’ direct line of fire because their members often live and work in densely populated areas home to many essential workers. The problems compound as residents get COVID-19 and end up in the hospital or clinic.

Most health workers in these settings aren’t consciously racist, says Tonia Poteat, a social medicine specialist at the University of North Carolina. But multiple studies show they have unconscious biases that influence their care, as when doctors downplayed Moore’s shortness of breath. And even well-meaning stop-the-spread tactics often have structural inequity at their core. Drive-up COVID-19 testing sites might be ideal for affluent or suburban residents, but not for those who don’t own a car. “A provider might think, ‘I’m treating everyone the same,’ but everyone’s needs aren’t the same,” Poteat points out.

To address such inequities, health care providers and lawmakers are creating new sets of best practices for equitable care. The Massachusetts Medical Society, which represents 25,000 doctors and medical students in the state, drafted an action plan in late 2020 that includes training providers in culturally adept communication and forging relationships with community groups that support people of color.

On the national level, U.S. House Rep. Ayanna Pressley (D-Mass.) recently introduced the Anti-Racism in Public Health Act, which would fund research into structural racism’s health impacts and create a National Center for Anti-Racism at the CDC. Down the line, U.S. lawmakers will need to allocate more funding to local and national public health agencies, says Kenyon, the chief health officer at Project HOPE. Public agencies can promote equal care by getting life-saving information and vaccines to underserved populations.

Rep. Ayanna Pressley called structural racism a “public health crisis that continues to ravage Black, Brown and Indigenous communities” in early 2021. (Credit: Tom Williams/Pool/Afp via Getty Images)

As they pursue greater equity, care providers must also rebuild trust with communities of color that have long suffered at the hands of the health system and other forces. “We need to include people of color in research trials and get informed consent from study subjects who have felt marginalized,” says Stanford Medicine emergency physician Michael A. Gisondi. The journey ahead will be demanding, but in this arena, COVID-19 seems to have pushed health care in the right direction.

5. Medicine From Home

COVID-19 restrictions meant doctors-in-training spent less time at bedsides last year. Instead, mentors walked them through a series of virtual consults. If the person on their screen had severe knee pain, would they send the patient for an MRI or opt for physical therapy? Established providers also scrambled to get comfortable with Zoom and remote exam tools like digital stethoscopes. (Yes, they exist, and are just about as accurate as the real thing.)

Some of the initial telemedicine shift happened out of necessity. Patients, doctors and trainees feared going into public places and getting exposed to the virus. But what began as a short-term workaround morphed into a lasting change to the medical landscape. Alongside “Work From Home,” “Medicine From Home” evolved — a concept that will likely continue to pick up speed post-pandemic.

Once providers started offering virtual visits on a regular basis, doctors and patients liked the results enough that these visits continued even as COVID-19 numbers declined. Pandemic or not, remote consults are often more convenient and safer for everyone involved. “It’s efficiency of practice for us,” says Gisondi. “It does reduce exposure to infectious diseases. Do you really want to visit your doctor in-office in the middle of flu season?”

Even so, shifting full-service care into virtual space comes with its own suite of challenges. While virtual visits help some patients feel safer from infection, others report that these visits feel less personal. Adapting to online consults will be easier for some specialists than for others. A dermatologist might have an easier time diagnosing a skin lesion virtually than, say, an oncologist would checking on a tumor’s growth.

But even visits that require in-person contact can be streamlined and made safer with telemedicine tools. If a patient shows up with a contagious virus, one doctor can enter the exam room with a tablet computer and send a video stream to specialists who weigh in from a remote location. The challenge ahead for providers will be figuring out just where to set the bar for in-person visits — but it’s safe to say that bar is already much higher than it was before.


Pandemic Numbers

  • 428 million COVID-19 tests recorded in U.S. labs, as of May 14. (Source: CDC)

  • 1.26 Billion Global vaccine doses injected as of May 12. (Source: WHO)

  • 3.3 million global COVID-19 deaths reported as of May 14. (Source: WHO)


Elizabeth Svoboda is a science writer in San Jose, California. Her latest book is The Life Heroic: How to Unleash Your Most Amazing Self.

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