What you need to know about Long COVID and how to reduce your risk

Scientists at the University of California, San Francisco have found that SARS-CoV-2 can persist in the body for years, potentially causing a long-COVID pandemic.

They are also investigating the surprising long-term risks of contracting COVID-19 during pregnancy.

Assistant Professor of Medicine Michael PelusoM.D., UCSF LINC Programstands for “Long-Term Effects of Novel Coronavirus Infection,” a university-wide effort to understand one of COVID-19's most enduring challenges. Valerie FlahermanMD, MPH, Lead Component National Institutes of Health Long-Term COVID Consortium, RECOVER – Or studying COVID to promote recovery.

Peluso and Flaherman tell us what we know and don't know about Long COVID.

What is Long COVID?

Peluso: There is no single photograph of Long COVID, which is one of the reasons it is difficult to study.

Still, when clinicians and researchers talk about long COVID, they're referring to medically unexplained symptoms that last for months or years after someone has COVID.

We don't know what causes it, why it happens to some people and not others, or how to make people feel better. We spend most of our time trying to figure that out.

What are the most common long COVID symptoms?

Peluso: Symptoms include “brain fog,” or problems with memory and thinking, shortness of breath, and fatigue — and by fatigue I don't mean just feeling a little tired, but bone-breaking fatigue, or what we call post-exertional malaise.

Post-exertional fatigue occurs when physical, cognitive, or even social activities that you were previously able to do easily cause debilitating fatigue for days afterward. This symptom is common in people who were fairly healthy before COVID-19 infection — for example, they would run many miles or go on long hikes — but can now only do a fraction of those things.

Some people have prominent gastrointestinal symptoms such as nausea, abdominal pain, and diarrhea, while others have genitourinary symptoms such as pelvic pain and menstrual problems.

Who is most at risk for long COVID?

Flaherman: In general, people who have had a more severe COVID infection are at higher risk of developing long COVID, as are older people, those with pre-existing medical conditions and those who have not been vaccinated.

What about pregnancy and Long COVID?

Flaherman: While we don't know for sure yet, our data suggests that pregnant people may be at lower risk of developing Long COVID when compared to estimates from the adult RECOVER cohort. Still, Long COVID has uniquely dangerous effects on pregnant women. In a recent study conducted in collaboration with the University of Utah, nearly 1 in 10 pregnant women developed Long COVID. The study included nearly 1,500 people who had COVID while pregnant.

The most common symptom was post-exercise fatigue.

Can pregnant women transmit the virus to their unborn babies?

Flaherman: It's hard to know for sure, but if it's possible, it seems pretty rare.

What about newborns?

Flaherman: If a pregnant woman is infected with SARS-CoV-2 at the time of delivery, she can transmit the virus to her baby, as can anyone else in the delivery room. Mothers who were infected with SARS-CoV-2 at the time of delivery are advised to wear a mask when holding or breastfeeding their baby and to wash their hands frequently for 5 days after their fever has subsided.

Should new mothers infected with SARS-CoV-2 continue to breastfeed?

Flaherman: Yes, breastfeeding benefits your baby as it gives your baby some immunity to SARS-CoV-2, which can help him fight COVID-19 if he becomes infected. Mothers are encouraged to breastfeed their babies even if they have COVID-19, but they should wear a mask and wash their hands frequently.

When will Long COVID go away?

Flaherman: Among the pregnant women and new mothers we studied, those who developed long COVID had symptoms for nearly a year, on average.

Peluso: Most data indicates that the condition can last for years and that the percentage of people who fully recover is surprisingly low, sometimes as low as 10%.

What causes Long COVID?

Peluso: If you had told me four years ago that there would be a debate about the persistence of SARS-Cov-2 in the human body, I would not have believed it.

Recently, we reported that SARS-CoV-2 proteins can be found in the blood of some people after COVID-19 infection. This had to have come from somewhere. Our hypothesis was that fragments of the virus remain in tissues and organs, and at UCSF we started by looking at the digestive tracts of people with long-term COVID-19 infection. This is relatively easy to do; anyone who has had a colonoscopy will know this.

What they found was surprising: Some people with long COVID-19 still had pieces of the virus in their digestive tracts one to two years after they had COVID-19, and UCSF was the first to show that the virus may still be active.

Were the virus fragments you found replicating?

Peluso: We don't know for sure yet, but we have detected double-stranded RNA that should only be present if the virus is replicating through its life cycle.

Why does SARS-CoV-2 persist in the body?

Peluso: One reason is that the virus is in an area isolated from the immune system — for example, immune cells may have walled it off when trying to contain it. Another possibility is that the virus hides in hard-to-reach areas, such as the nervous system. A third possibility is that the virus evolves after infection, making it less susceptible to immune responses.

There are a number of different scenarios that could happen, and we don't yet know which one is true, but this is a big clue that we're pursuing.

How can I reduce my risk of long COVID?

Peluso: The best strategy is to not get COVID in the first place, but that's easier said than done. I'm still pretty diligent about wearing a mask and getting vaccinated, because studies have shown that staying up to date on vaccines when you do get COVID-19 can reduce your risk of getting long-term COVID-19.

It is not yet known whether taking paxlobucil or any antiviral medication will reduce the risk of long-term COVID-19, but it may be helpful and is worth discussing with your doctor.