COVID-19 case counts are beginning to fall again in the San Francisco Bay Area. But for many of the hundreds of thousands of residents infected in the past month, a huge question lingers: Am I going to develop long COVID?
To get answers, we reached out to several experts who are working with long COVID patients in the Bay Area and beyond. They helped us understand what, exactly, researchers know so far — and what there still is to find out.
What is ‘long COVID’?
There isn’t a good definition of “long COVID” yet. The U.S. Centers for Disease Control and Prevention starts the clock on long COVID four weeks after people are infected, while the World Health Organization defines it as symptoms that stick around longer than four months. Many researchers also believe extended symptoms can be separated into several distinct syndromes.
One issue is “post-intensive care syndrome,” a serious condition related to post-traumatic stress disorder that can affect people in the ICU for any reason.
Whether or not you end up in the ICU, COVID can cause injuries that take a long time to heal. Some of those are common to other respiratory illnesses. If you develop severe pneumonia from any virus or bacteria, including COVID, it can take as long as six months to get back to normal; in the meantime, you might have shortness of breath, coughing and fatigue.
Severe COVID also increases your risk of heart disease. In one study before vaccines were widely available, about 1 in 1,000 people diagnosed with COVID-19 also developed a type of heart inflammation called myocarditis within a month. In another pre-vaccine study, which has yet to complete peer review, 15% of people with confirmed COVID infections were diagnosed with heart disease within the next year. When researchers looked at data from 2017, only 10% of similar people had developed cardiac problems.
Some people develop symptoms that look very similar to chronic fatigue syndrome, also known as myalgic encephalomyelitis. That kind of “post-viral syndrome” can develop after all kinds of infection, including after mild or even asymptomatic cases of COVID. People may feel extremely tired, no matter how much they sleep; have extreme difficulty concentrating, also known as “brain fog”; and get exhausted just from walking across the room.
There are likely connections between the immune response to the virus and all these diverse symptoms, according to Mady Hornig, an associate professor of epidemiology at Columbia University’s Mailman School of Public Health, who specializes in myalgic encephalomyelitis. She developed long COVID herself about four months after being infected. For more than a year, even mild exertion could trigger her heart to race and her blood oxygen to drop.
“Infection-triggered syndromes are certainly not a surprise,” she told SFGATE. “There’s so much that we really need to understand about what is actually wrong.”
How is it treated?
That all depends on the symptoms, said Dr. Lekshmi Santhosh, medical director of UCSF’s post-COVID clinic. “Someone who was hospitalized and on a ventilator will have different needs than someone who was never hospitalized, who has significant fatigue and post-exertional symptoms. Treating respiratory symptoms is different than treating headaches and brain fog,” she told SFGATE by email.
Dr. Linda Geng is the co-director of the Post-Acute COVID Syndrome Clinic at Stanford in Palo Alto, and said the most common symptoms she sees in her clinic include fatigue, brain fog, exertional intolerance and sleep issues.
“Encouragingly, we do see many patients get better over time, though there are patients who have now had symptoms lasting longer than a year, so we need to make sure we continue to provide support and resources for all long COVID patients,” Geng wrote in an email.
What about omicron?
Even though it’s now the dominant variant in the U.S., omicron hasn’t been around long enough for researchers to get a handle on what happens long-term. It’s clear, though, that omicron results in less severe disease than delta does. That’s true even for unvaccinated people, although they’re still much more likely to get very sick, or even die, than people who have been immunized.
I’m vaccinated. How likely am I to have long-term symptoms?
Since vaccinated people are much less likely to get very sick, they’re also less likely to have injuries that take a long time to heal, like lung and heart damage. Even if you do get sick enough to go to the hospital, it’s extremely unlikely you’ll have to be treated in the ICU. (People infected with the omicron variant are unlikely to need the ICU, whether or not they’ve been vaccinated.)
“Most of our patients had acute COVID prior to vaccination,” Geng said. “Thus far we have not seen many new patients who have long COVID from breakthrough vaccinations, but we will need to see as time passes how the patterns emerge.”
One of the only published studies looking at vaccination status was published in September 2021, when delta was the dominant strain, and before booster shots were widespread. Researchers in the United Kingdom asked people to self-report COVID symptoms through an app. A month after being infected, people who had received two vaccine doses were about 50% less likely to report symptoms than people who hadn’t received any shots.
“We need more data to continue to evaluate the impact of vaccines, specifically boosters in the age of Omicron and whether the probability of infection is the same,” said Dr. Peter Chin-Hong, an infectious diseases expert at UCSF, via email.
Why is this so hard to study?
Research on the prevalence of long COVID is hugely varied, with peer reviewed reports claiming anywhere from 3% to 80% of people will have extended symptoms. (Chin-Hong estimated that number is about 10% to 20%, noting that vaccination significantly reduces the risk.) Obviously, there’s a huge disparity between those numbers, even accounting for differing definitions of long COVID.
The biggest issue is that it takes a long time to do this kind of research. Most of the work now being published uses data from patients infected before vaccines were widely available. While lots of vaccinated people with long-term symptoms are being followed, most were infected when the most common strain of SARS-Cov-2 was delta, which causes more severe disease than the now-dominant omicron variant.
It’s also very hard to conduct public health research in America, because our medical data is scattered across tens of thousands of systems that can’t talk to one another. That means a lot of this research is being conducted in countries with national health systems like the UK, where the most common vaccine uses a different technology than the Pfizer or Moderna shots.
When will we know more?
It’s hard to say. Vaccines have done such a good job at preventing serious disease that many immunized people either don’t know they’ve been infected or use at-home tests without reporting positive results to anyone. That means it may take a long time for people to connect long-term symptoms to a COVID infection.
The federal National Institutes of Health has pledged to spend $1.15 billion on research into long COVID.
To Hornig, the pandemic represents an enormous opportunity — and obligation — to learn as much as we can about this and other post-viral syndromes. “So many people got this at the same time, we’re finally looking at all sorts of nervous system disorders,” she said. “But we have so far to go before we know what to do.”