Table of Contents
- Most people are potentially infectious with COVID-19 for 10 days.
- People are typically the most infectious the first five days after they are diagnosed.
- Antibodies to the virus can last for months after infection or vaccination.
Emergency room visits for COVID-19 are increasing across the country, suggesting that cases of the virus are also on the rise. If you happen to contract COVID-19, it’s understandable to wonder how long COVID stays in your system, both in terms of infectiousness and protective antibodies.
As with every illness, there is a range. But as a rule of thumb, here’s what you should know.
How Long Are You Infectious?
There is some variability in how long you’re infectious with COVID-19, Thomas Russo, MD, a professor and chief of infectious diseases at the University at Buffalo in New York, told Verywell. “Most people no longer have detectable infectious particles by day 10, but it can vary,” he said.
The Centers for Disease Control and Prevention (CDC) has isolation information for people with COVID-19 that notes that patients are most likely infectious during the first five days after they test positive for COVID-19. However, the CDC’s recommendations also suggest that people wear a mask for up to 10 days after testing positive to avoid getting others sick.
The CDC also said online that people who have severe COVID-19 may be infectious beyond 10 days and may need to isolate for up to 20 days.
“If you’re immunocompromised, you could potentially be infectious for a much longer period of time—20 days vs. 10 days, as well,” Russo said.
“Children tend to test positive longer,” William Schaffner, MD, an infectious disease specialist and professor at the Vanderbilt University School of Medicine, told Verywell.
How Long Do You Shed COVID-19?
Viral shedding is a term used to describe how long a virus is still detected in your body after you get sick, Schaffner explained. When you “shed” a virus, you may be able to infect others.
“Over time, the amount of virus you shed diminishes,” Schaffner said.
Not all viral shedding will make someone else sick, especially if you shed at low levels.
It’s unclear how viral shedding has changed during the pandemic, but there is data on how long it may last now. One study published in 2022 in the journal Emerging Infectious Diseases analyzed samples from patients who were infected with the Omicron variant between November 29 and December 18, 2021. (Subvariants of Omicron are currently circulating in the U.S.) The results showed patients shed the most virus between days two and five after their diagnosis. However, the researchers also noted that people with mild or asymptomatic COVID-19 cases still shed infectious virus six to nine days after they developed symptoms or were diagnosed, even when their symptoms stopped.
“There are rare people who continue to shed virus for a more prolonged period of time—a month, for example,” Schaffner said. “But for all practical purposes, 10 days is a good rule.”
How Long Do COVID-19 Antibodies Last?
Data published in the journal The Lancet in February 2023 offers some insight on the duration of COVID antibodies—proteins made by the immune system in response to an infection or vaccination. For the study, researchers analyzed data from 65 studies from 19 countries and compared the risk of getting COVID-19 again in people who recently had the virus to those who hadn’t been infected. The researchers learned that having the Omicron variant of COVID-19 lowered the risk of being hospitalized and dying from a new infection by almost 89% for 10 months, thanks in part to protective antibodies left behind from infection.
That duration of antibodies seems to have gotten stronger over the course of the pandemic. People who were previously infected with a variant other than Omicron were just 74% likely to be protected from getting infected again after a month. That number dropped to 36% after 10 months had passed since the initial infection.
In the case of antibodies from vaccination, a study published in The New England Journal of Medicine found that most people receive at least six months of protection after getting the shot.
“Measurable levels of antibodies do decrease over time,” Russo said. “The most durable protection is in people who have antibodies from vaccination and infection.”
Factors such as age and individual immunity can also influence how long antibodies last in any given person, Schaffner said.
“Older, frail people and those who are immunocompromised will have antibodies that wane more than a young person who is fit as a fiddle,” he said. “But this is not a black and white phenomenon.”
What This Means For You
Doctors say that most people with COVID-19 will no longer infect others after 10 days have passed since their diagnosis or start of symptoms. Many people are also protected from being reinfected with COVID-19 for six months. However, factors such as your individual immune system, your age, your health status, and the variant you were infected with, can all play a role.
The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.
Centers for Disease Control and Prevention. COVID data tracker.
Centers for Disease Control and Prevention. Isolation and precautions for people with COVID-19.
Centers for Disease Control and Prevention. Ending isolation and precautions for people with COVID-19: interim guidance.
Takahashi K, Ishikane M, Ujiie M, et al. Duration of infectious virus shedding by SARS-CoV-2 Omicron variant-infected vaccinees. Emerg Infect Dis. 2022;28(5):998-1001. doi:10.3201/eid2805.220197
COVID-19 Forecasting Team. Past SARS-CoV-2 infection protection against re-infection: a systematic review and meta-analysis. Lancet. 2023;401(10379):833-842. doi:10.1016/S0140-6736(22)02465-5
Doria-Rose N, Suthar MS, Makowski M, et al. Antibody persistence through 6 months after the second dose of mRNA-1273 vaccine for Covid-19. N Engl J Med. 2021;384(23):2259-2261. doi:10.1056/NEJMc2103916
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