COVID-19 1 Year Later: What Have We Learned?

It’s been more than a year since the first case of COVID-19 was diagnosed in the United States.

And while we’ve been busy washing our hands, wearing masks, and occasionally scrambling to get toilet paper — remember that? — doctors and scientists have been working to understand the virus that’s gotten us here.

In the past year, “we’ve made a tremendous amount of progress that’s both overwhelming and incremental,” said Paula Traktman, PhD, a virologist and professor of biochemistry and molecular biology at Medical University of South Carolina in Charleston.

“Overwhelming because who knew we’d be spending every waking hour thinking about this? And incremental because I don’t think we’ve learned crazy new science about the virus, but we’ve learned crazy new stuff about the pandemic,” she said.

Here are some of the most significant questions about COVID-19 that experts have been able to answer in the past year — and a few that remain a mystery.

What have we learned about where this coronavirus came from?

A year ago, scientists theorized that this new coronavirus, SARS-CoV-2, probably originated in bats, then another animal passed it on to humans.

That still appears to be the most plausible theory, according to a monthlong World Health Organization (WHO) investigative report in China.

For the general public, this might sound like the plot of a sci-fi thriller, but virologists aren’t surprised.

SARS-CoV-2 is actually “a new flavor of a familiar virus,” Traktman said. “When you look at [it], it tells a familiar story.”

There are actually seven different human coronaviruses. The four milder strains have been circulating in humans for years and are believed to be responsible for up to 30 percent of common colds.

But SARS-CoV-2 more closely resembles the other two potentially lethal strains: SARS (severe acute respiratory syndrome) and MERS (Middle East respiratory syndrome).

“What’s been unusual is that SARS-CoV-2 has been much less lethal than SARS and MERS but much more global. It’s gone on for what seems like forever, and it’s had a really broad and durable impact. That’s the news,” Traktman said.

What have we learned about COVID-19 ‘long haulers’?

Typically, mild cases of COVID-19 last about 2 weeks, while people with severe cases may take up to 6 weeks to recover.

However, about 10 percent of people who develop COVID-19 have symptoms that linger for months.

There’s a lot about these “long haulers” that still mystifies doctors. They’re people of all ages, for starters. Some have no underlying health conditions, and some have been only mildly sick with COVID-19.

Post-COVID-19 syndrome can also span a wide range of symptoms, from severe fatigue and brain fog to nausea, headaches, and loss of taste and smell.

“It’s almost as if their immune system is still trying to fight something that isn’t there,” said Dr. Bradley Sanville, a pulmonary and critical care physician at the UC Davis Medical Center Post-COVID-19 Clinic in Sacramento, California.

Some long haulers have one lingering symptom, while others have 15.

“That makes it hard to parse out what’s going on and whether or not there’s one unifying problem… We don’t know if people will just get better with time and, if so, we don’t know what the time frame is. It’s tough,” Sanville said.

Over the past year, medical experts have been primarily focused on fighting the virus, but “hopefully enough people get vaccinated and the spread of COVID slows enough so that we can take a better look at this group of people,” Sanville said.

Why does the virus affect kids differently than adults?

We now know that children experience far lower infection rates than adults.

Kids between the ages of 5 and 17 years make up less than 10 percent of all confirmed COVID-19 cases in the United States, while those under 4 years old account for just 2 percent.

But experts still aren’t entirely sure why.

One intriguing theory has to do with a protein called angiotensin converting enzyme 2, or ACE2, that’s found on cells throughout the human body.

SARS-CoV-2 has to bind itself to ACE2 to gain entrance into cells. Children naturally have less ACE2 than adults, a physiological difference that may help them avoid severe infection.

“The hypothesis around ACE2 receptors is still considered likely,” said Justin Lessler, PhD, MHS, an associate professor of epidemiology at Johns Hopkins Bloomberg School of Public Health. “But I don’t see us as having definitive answers at this point.”

What medications do and don’t help treat COVID-19?

Over the past year, “the medical community has definitely learned a lot about how to manage [COVID-19] patients,” Traktman said.

Treatments that have been found to help people with COVID-19 “have ranged from the simple to the interventionist, and [as a result] we have many fewer people going on respirators now and dying,” Traktman said.

Among the valuable finds include dexamethasone, a common steroid. It can help prevent the body’s immune system from dangerously overreacting to the new coronavirus.  

Also, a simple strategy called proning — positioning people on their stomachs — can help them breathe more easily. (When you lie down on your back, your heart and stomach press down on your lungs, requiring more oxygen.)

As far as medications go, “antibody cocktails are still trying to find their niche,” Traktman said. “It makes sense that if you give people antibodies to fight off the virus, it should help. What we don’t know yet is when to give them and to whom… That’s still very much in the air.”

In October, the Food and Drug Administration (FDA) approved the first treatment for COVID-19, an antiviral drug called remdesivir (Veklury).

Early research showed that people who received remdesivir recovered faster and were less likely to become severely ill. However, other studies haven’t been able to duplicate those results.

A WHO trial of more than 11,000 people in 30 countries found that remdesivir, along with three other repurposed antiviral drugs like hydroxychloroquine, had little to no effect on COVID-19.

But if antiviral treatments still remain out of reach, at least we now have COVID-19 vaccines — and not just one, but three so far in the United States.

“Vaccines have been phenomenal advances,” Traktman said. “Faster than anyone could have imagined, and in a way that’s been safe and very effective.”

Has misinformation made the fight against COVID-19 harder?

It’s not “fake news” to say the answer to this question is yes.

“Misinformation has been particularly challenging during the pandemic in part due to the notoriety and reach of the individuals spreading it,” said Maimuna Majumder, PhD, a computational epidemiologist at Boston Children’s Hospital and an instructor at Harvard Medical School.

For instance, when former President Donald Trump mused last April that bleach injections could be a potential treatment for COVID-19, online searches for drinking and injecting disinfectants spiked the next day, according to research from Majumder and team.

So did online searches for poison control centers, which saw upticks in poisoning cases due to ingesting disinfectants.

“Medical misinformation certainly isn’t a new phenomenon,” Majumder said. “However, in many ways, the Trump administration made medical misinformation more mainstream than it used to be.”

What mistakes were made in educating the public about masking? 

From the start of the pandemic, it seemed clear that respiratory droplets could transmit the coronavirus.

And sure enough, we now definitively know that coughing, sneezing, singing, talking, and simply breathing can launch the virus into the air.

Because of that, it’s clear that masks do a lot. “Just having that barrier stops the biggest droplets. They get trapped in the mask. And the smaller droplets can’t permeate the cloth well,” Traktman said.

Yet the Centers for Disease Control and Prevention (CDC) waited until last July to finally endorse wearing masks.

And even then, “there was this confusion over whether to describe mask wearing as a way to protect yourself or protect other people,” Traktman said.

“Protecting yourself led to some people saying, ‘I’m big and tough. I won’t get sick.’ Protecting others, which appealed to others who were more community-oriented, led to some saying, ‘I’ve been very careful, I’m not sick. I don’t need to,’” she said.

“Making mask wearing optional and open to interpretation was not very effective,” Traktman said.

Several studies have documented the rate of COVID-19 transmission in different cities before and after mask ordinances.

“The data is black or white,” Traktman said. “When communities instituted mask ordinances, rates of transmission plummeted. It really does work.”

Why did the absence of a national plan make controlling the pandemic more difficult? 

“COVID-19 is an infectious disease, so what’s happening to other people in other places impacts us,” Lessler said.

“If one area takes one approach to control and their neighbors right across the state line take a very different approach, that impacts how both approaches work,” he said.

Coordinating actions can make control of the virus more effective, Lessler said. And consistency and clarity from the top down helps people at the state and local levels make better-informed decisions.

“Having central guidance about what is known to work and isn’t known to work, assistance to those localities, and perhaps most importantly, some sense of what the metrics are that constitute success or mean it’s time to change your actions — these are all critical to helping control efforts,” Lessler said.

As an example, “we never had the conversation about whether our goal in control was rapid elimination of spread or just keeping things tamped down enough so our hospitals and healthcare systems weren’t overwhelmed,” Lessler said.

“Effectively, the latter has been what we’ve done, but we’ve never had that conversation, and that’s led to a lot of confusion and frustration,” he said.

What can we expect life to be like a year from now? 

Once we reach herd immunity through vaccinations and infections, “the virus becomes cornered and doesn’t spread very well because it can’t find enough people to spread to,” Traktman said. “I think then we will probably only wear masks under certain circumstances.”

These circumstances may include sitting in a crowded movie theater for 3 hours, or when squeezed onto a subway during rush hour.

“And are we really going to blow out candles again on birthday cakes? I don’t know,” Traktman said.

But just getting to that point “depends so much on how the virus evolves,” Lessler said, “and even more on how individuals and governments decide to react to the changing situation.”

Experts are pretty good at figuring out where things could be headed in the short term, as well as forecasting many years into the future, Lessler said.

But just 1 year out? “It’s hard to say anything with much certainty,” he said.