Is Five Days of COVID Isolation Enough? New BU Study Has Some Answers
Results showed majority of those who test positive are negative before 5 days, but virus lingered in 17 percent
Is Five Days of COVID Isolation Enough? New BU Study Has Some Answers
Results show majority of those who test positive are negative before five days, but virus lingered in 17 percent
When the Centers for Disease Control and Prevention (CDC) said in January it was shifting its recommended isolation period for people infected with COVID-19 from 10 days down to 5 days, followed by 5 days of mask-wearing, there were some concerns or questions about whether 5 days of isolation was too short. In the pandemic’s early days, the CDC had started out recommending 10 days of isolation and 14 days of quarantine, so 5 days seemed like a significant reduction.
Now, a new study from researchers at Boston University and Boston Medical Center offers some clues about whether five days is sufficient to ensure the broad safety of both those infected and the community at large. (BU’s COVID-19 policy mirrors the CDC guidelines.) The short answer appears to be yes—with a few caveats.
Researchers tracked a cohort of BU students who’d tested positive for SARS-CoV-2 as part of the University’s broader testing program, asking them to self-perform daily swabbing and symptom screens for the next 10 days. The majority of those in the study who first tested positive were no longer positive after five days in isolation (in fact, most of them tested negative after three days of isolation). However, among 92 active participants in the study (all were fully vaccinated), 17 percent did still test positive after five days, which is why the second component to the CDC, and BU, guidelines—consistent mask-wearing for five additional days—remains vital.
The study’s conclusion says the majority of the infected cohort had converted from positive to negative by day six, and that “rapid antigen testing may provide reassurance of lack of infectiousness.” Masking for a full 10 days “is necessary to prevent transmission from the 17 percent of individuals who remain culture positive after isolation,” the study says. The research is considered a preprint study, which means it is in the process of being peer-reviewed. But because of the urgency of any funded research involving the coronavirus, the researchers are making their findings public.
The lead investigators on the study are Karen R. Jacobson, a School of Medicine associate professor of medicine in the Section of Infectious Diseases; John H. Connor, a MED associate professor of microbiology and a virologist at the National Emerging Infectious Diseases Laboratories; Catherine M. Klapperich, a College of Engineering professor of biomedical engineering and director of BU’s Precision Diagnostics Center and BU’s Clinical Testing Lab for COVID-19; and Tara Bouton, a MED assistant professor of medicine in the Section of Infectious Diseases.
The Brink spoke with Bouton about the study and the findings.
with Tara Bouton
The Brink: Can you first talk about why you felt it was important to conduct this study?
Bouton: There has been an ongoing collaboration with the Massachusetts Consortium on Pathogen Readiness, looking at COVID-19 viral variants and if they cause differing symptoms and duration of infection, and if we are seeing escape of the virus from people after being fully vaccinated and boosted. Essentially, how were the viral dynamics changing? Then, when we brought this to BU, they raised the importance of trying to understand the timing for release from isolation. Did a young, fully vaccinated university campus population need to remain in isolation as long as others? Isolation guidelines have changed, and we are only just beginning to understand the mental health impact of isolation, along with how long different individuals may remain infectious.
The Brink: The isolation guidelines changed a lot, from 10 days to 5 days, with strict mask-wearing. So, who participated in this study?
Bouton: The BU student body is a lot like the patient population we serve at Boston Medical Center. They can’t always socially isolate because of congregate living situations. It’s very difficult to interpret the guidelines in the context of roommates and other situations.
Through generous support within the BU community, starting in the fall semester, we very quickly recruited a cohort and are nearing completion of our anticipated enrollment of 150 people. We are always looking for populations that are easier to access, so being able to readily collect samples from the campus community was important. We were able to work with the isolation dorm that BU set up. And then when the duration shortened for isolation, we transitioned to include off-campus collections, as well.
The Brink: So, the people in this study don’t necessarily reflect a broad swath of the general population.
Bouton: Right. This cohort is limited to young healthy people who presumably have optimal response to the vaccine. So, it’s not necessarily broadly applicable to those who are older or under-vaccinated.
The Brink: Did you find what you expected to find or did anything surprise you?
Bouton: One of the most surprising things to us was that we did not see a significant impact of the booster vaccine on the amount of time people remained infectious. At the population level, we know boosters are helping reduce infections. But that probably means the majority of the booster is helping to prevent infection, rather than changing how long it can be transmitted once you are infected.
The Brink: And what happens at the five-day mark?
Bouton: In our young, healthy, fully vaccinated cohort, a majority went from positive to negative culture by day three. A large percentage never had a positive culture after study enrollment. And then there is this 17 percent that go on to have this positive culture beyond the five days. But that’s a definite minority of the overall population. And the hope is that strict mask-wearing will limit the spread of the disease in that minority.
The Brink: Based on the findings, how do you feel about the CDC’s guidelines? Is there any reason to consider five days too short?
Bouton: I don’t think so. Any longer and you would be holding a huge proportion of the population in isolation unnecessarily. We are increasingly coming to recognize the economic impact—and also the mental health impact—of isolation. I do feel comfortable with the current guidance, but would stress the importance of strict masking for an additional five days.
The Brink: Have you shared the results with the CDC? And what are your next steps?
Bouton: We have presented these results on regional calls, where there is CDC membership. The preprint process, sharing manuscripts before peer review, has been especially important for disseminating results quickly during the pandemic. And next steps are to do a more detailed model looking for associations with or ways to predict those who remain positive after five days of isolation.
This interview has been condensed and edited for space and clarity.
This study was funded by the Massachusetts Consortium on Pathogen Readiness (MassCPR) and Boston University.
The “strict masking” requirement is not currently properly substantiated by the scientific literature I have seen. The main evidence on community masking is mixed, with three Randomized Controlled Trials (specifically for COVID) failing to show any clear benefit for the university-student age cohort.
If you are really worried about the small risk of transmission after 5 days, why not just say it that way and let students decide how to responsibly maintain caution thereafter? We let them drive and defend their country with their lives … why can’t we trust them to behave responsibly when feeling sick?
Giving students unsubstantiated confidence in a mask is not scientifically appropriate.
Because just as young adults are responsible for most car accidents, snd unwanted pregnancies due to unsafe practices , we should understand they are likely not to mask up for the remainder of the 5 days.
Hello, I had two covid vaccines and one booster six months ago. I came down with covid symptoms on Tues April 12.
I used a home kit to test on Wed April 13th. I tested positive
I received monoclonal antibody infusion on Thurs April 14th.
I have been symptom and fever free for 24 hours. I tested positive this morning. I am 74 years old.
If 5 days is sufficient enough to stay isolated, and the next 5 days is strict mask wearing, how can there be strict mask wearing when kids only get 5 days to stay home and are allowed to go back to school and sit and have lunch with other children, this will surely pass the virus on to other children thus continuing spreading of covid virus and more lives lost. I do not agree with 5 days only self isolating, should be at least 10 days minimum. In this study there is proof that 17% were still testing possitive and able to pass the virus, 5 days is insufficient.
I guess, you can say…IM NOT VERY TRUSTING IF MY GOVERNMENT LATELY! Joe Biden, said 2 weeks ago, that this winter there will be a new surge of the virus! Really! Are they letting our guard down…for a 5 day isolation, it still in our system and out in amongst others…and so the virus spreads! And here we go again…ANOTHER PANDEMIC, JUST LIKE “JOE”, said would hit us this winter! Far to much flip flopping on this China Virus, from the Oval Office! Just 5 days and home free? I don’t think so…is this how Joe’s winter pandemic begins, by going out into the public after 5 days…and passing it on to others….
AND HERE WE GO AGAIN!
Covid is rising due to the facts the masks are off, indoor dining is no longer restricted, and social distancing is no longer required. Now the covid numbers throughout the United States have once again risen to over 100k a day. Also self isolating for only 5 days is accepted while having covid when we know that not everyone clears the virus in only 5 days. So what did we really expect here when we act as if this virus doesn’t exist anymore..
Even if you have many of the rules in place you want, it comes down to people staying home and isolating with COVID and not going to a friends house with 20 people all inside or skipping the neighbors wedding. We are generally selfish. Rules won’t stop that.
Thank you for your study it was very helpful and informative. I do have a question. Are you still contagious if you tested postive on April 17th(day 1) tested again on April 21st and 22nd ( days 5&6) and was negative but then tested on April 26th (day10) and was positive.
Only symptom was a little scratchy throat 1st day then no symptoms. Fully vaccinated with a booster, isolated for 5 days then masked. On day 10 started with a very sore throat and tested positive.
Re students who were positive, then isolated and tested negative after 3-5 days, are they not resilient? Do they also have to wear masks for 5 days?
It is clear that the five day recommendation was based as much on economic and isolation impacts as it was on the ability to spread to other non-infected individuals. It is difficult to see a strict medical basis for this decision and it is clear that it becomes one of convenience for these young healthy, vaccinated, non-susceptible individuals.
How about a study that looks at keeping individuals who are at risk ( rather than young healthy individuals) and focuses on protecting susceptible individuals rather than on the convenience of the young and healthy students.
I am 70 yrs old. I Tezted positive 7 days ago today.; with moderate symptoms. I home tested o day 7 still show positive. My question is I work part-time in a dept. store; I don’t feel safe going back. I have only had a slight headache but no other systems. Should I isolate a little longer?
I do not think 5 days are enough, 17% can cause a big trouble for others. Once the person go back the society, the person may have trouble to keep the masker on for eating lunch, feel too hot, touch everything the others do.
I think it should require a negative result before stopping isolation. Testing kits should be free test for everyone. Today my husband went to test. He was told his insurance does not cover, he needs to pay $150 for a test in Walgreens. I think all Covid tests free can encourage people to do the test. Otherwise I heard some people even do not want to test, since you got it or not, no effect medicine. Doctors most time tell you drink a lot of water and Vc, zinc from counter. Some people even do not want to test since most of them are not very sick. The Covid will keep longer if we do not care enough.
There was never any valid health reason to inject healthy young people. This is an entirely different agenda. 17% is a small minority, she says. 17% is close to one fifth of all of these injected kids. Where is the comparison with a cohort of healthy young people that were not injected, for these minor variants like omicron and BA5 and so on?