Long COVID refers to lasting effects

Dear Dr. Roach: Can you elaborate on “long COVID”? Specifically, do people experiencing long COVID carry the virus for an extended period? Are they contagious during long COVID?

S.E.

Answer: People with normal immune systems are almost never contagious after about 10 days following the onset of symptoms of COVID-19. The greatest period of contagion is during the two days before onset of symptoms through the day after they start, which is why masking is so important. People can be highly contagious without even knowing they have the disease. People with severe immune deficiency may be contagious for a longer period of time.

“Long COVID” refers to persistent symptoms after the virus is gone, long past the infectious period. There is no evidence that people with long COVID are infectious for longer times than people who have mild or no symptoms.

There are many viruses that may continue to cause symptoms long after the acute period. Some viruses may cause damage to various tissues and organs — polio is a classic example. More than 99% of people have just a mild cold symptom with polio and get completely better, but a sliver of people will have damage to the nerves and develop muscle paralysis, sometimes fatally. It took many years to work out the mechanism of how polio causes these long-term symptoms; likewise, how COVID causes the longterm symptoms it causes is not yet well understood.

The incidence of long COVID varies by study, but the lowest number published I have seen is 10% of people continuing to have symptoms for three months after infection.

Many organ systems can be affected long-term by COVID-19, but fatigue, “brain fog,” sleep disturbances, chest discomfort and shortness of breath are some of the most common symptoms people with long COVID will notice.

No vaccine (other than live vaccines) has ever had long-term complications that haven’t shown up right away. Those who remain unvaccinated don’t seem to realize that they risk not only severe disease and death from COVID-19, but also the possibility of longterm debilitating symptoms.