In this Q&A, we speak with epidemiologist Kelly Kamm about virus latency, isolation versus quarantine, contact tracing, and why medical guidelines continue to change.
Kelly Kamm is an epidemiologist and assistant professor of kinesiology and integrative physiology at Michigan Technological University. Kamm's expertise has been vital to informing the University's response to the COVID-19 pandemic. Here, she explains some of the more complicated aspects of COVID-19 in a college setting.
How Long Am I Contagious?
Q: What is the latency period of the SARS-CoV-2 virus, which causes COVID-19?
KK: The virus can take between two and 14 days for someone to develop symptoms or test positive from the time they are exposed. This is called the incubation period. Many factors impact the range of the incubation period. If you were exposed on Monday the 1st and had a COVID-19 test on the 5th, only about half the people who are infected will have a positive test or have symptoms at that time. Just because you test negative on day five does not mean that you are not infected; you could still test positive up to 14 days after the exposure.
What's the Difference Between Isolation and Quarantine?
Q: How does the incubation period relate to how long a person needs to isolate or quarantine?
KK: If someone tests positive for the virus - whether or not they have symptoms - they are infected and must be isolated. Their time in separation is based on the infectious period, which is how long they are able to spread the disease to other people. The infectious period differs between individuals, but can be determined based on their symptoms and whether those symptoms are resolving, or a specified time period if they tested positive but never develop any symptoms.
Q: So, what's the minimum a person would need to isolate if they have no symptoms?
KK: If they test positive, but have no symptoms, they will be under isolation for a minimum of 10 days. If they develop symptoms anywhere in that 10 days, how long they stay in isolation depends on resolution of symptoms.
Q: Are you saying that a person can be infectious to others as long as they have symptoms?
KK: Yes. The length of the infectious period due to the virus has a lot to do with the individual and their particular disease journey. Someone with a severe case will have a much longer infectious period than someone with a mild case.
Current Centers for Disease Control [and Prevention] guidance is that a fever has to be entirely resolved for at least 24 hours with no medication to bring it down. Other symptoms (cough, loss of sense of smell, sore throat, shortness of breath) have to be improving and it must be at least 10 days since symptoms began.
The shortest time period of separation is 10 days if there are minimal or no symptoms, but the isolation period can be much longer than that in severe cases.
Q: How is quarantine different from isolation, then?
KK: We quarantine people who have been exposed but we don't yet know if they are infected or not. Someone with COVID-19 is infectious for one to three days before they experience symptoms. The quarantine is meant to prevent someone who is infected from spreading the disease during that period when they are infectious but do not know it. Because people can become positive for the virus anytime during a 14-day period after exposure, it is important to stay separated from others for that full quarantine period.
However, if you have multiple people in a household, you can be in quarantine a long time.
If one of your roommates tests positive and you cannot completely separate yourself from this roommate, you are continuously exposed to that roommate. That means that your last exposure, and day one of your 14-day quarantine, begins on the last day your roommate is infectious. So, if your roommate recovers after 10 days, your separation from other people includes the 10 days your roommate was infectious plus an additional 14 days (24 days total).
If one of your roommates tests positive but you are able to fully separate that roommate from the rest of the house, your quarantine starts the day your roommate was isolated from you. But if a second roommate tests positive on day 10 of your quarantine period, your quarantine will reset because you have a new exposure. Every time you have a new exposure to someone with COVID-19, your quarantine restarts, and you will need to be in quarantine 14 days after your last exposure.
Q: If you do live with multiple roommates or family members and someone in the house is in isolation, can you share bathrooms or other living spaces as long as you're not in the same room at the same time?
KK: No. The person in isolation must have their own bedroom and stay in that room. It is best if they have a separate bathroom, but if that is not possible, there are strict disinfection and use guidelines that must be followed. Meals should be left outside the individual's bedroom and no one else should use those dishes. You must remain totally separate.
How Does the Virus Spread?
Q: Wow, that's intense. But I thought as long as you remain six feet away and aren't in the same room for longer than 15 minutes, you won't catch the virus.
KK: Six feet apart for no more than 15 minutes in an enclosed space is not a hard and fast rule. It's a good estimator, but not foolproof.
The novel coronavirus is typically passed to others through airborne spread. If you sneeze or cough or droplets are formed when you're talking or breathing hard, those droplets travel through the air. If they come into contact with the nose, mouth or eyes of someone who is susceptible, that is a route of entry.
The closer you are to that someone, and the longer you stay there, the more likely it is for this to happen.
Another way you can catch the virus is through indirect contact. If someone coughs into their hand and touches a doorknob, they may leave virus particles on that doorknob. If you touch that doorknob and then touch your eyes, nose or mouth, the virus can enter your body.
The key to preventing indirect spread is to wash your hands immediately after you touch things other people touch. Make sure to cough into your elbow, not your hands. Don't touch your face until you wash your hands.
How Does Contact Tracing Work?
Q: Michigan Tech is hiring people to work as contact tracers to make sure people who may have been exposed can quarantine themselves to keep the virus from spreading. How are you involved in contact tracing?
KK: I am helping recruit, train, and manage a team of student volunteers who will help the Western Upper Peninsula Health Department by conducting contact tracing in our campus community.
Q: I'm happy to report that at least 100 people have answered the call to become contact tracers. But how many do you need?
KK: It is very difficult to estimate how much time or how many tracers we need. So many variables go into the time it takes to trace contacts.
Q: What do the contact tracers do?
KK: When someone tests positive for COVID-19, the health department calls them and interviews them. The health department official asks about who the positive case might have been around during their infectious period to identify who meets the threshold level of a close contact who needs to be quarantined. The general definition of a close contact is someone within six feet of an infected person during the infectious period for at least 15 minutes.
Contact tracers work to notify the close contacts of the need to quarantine and help connect those in quarantine with Michigan Tech and community resources they may need.
If you think you may be a close contact, call the health department and they can help you determine if you were. The health department notifies us if close contacts include people from the campus community. Our campus team is also able to identify people who report they are a close contact through the Daily Symptom Tracker.
It's really important to answer your phone or listen to your phone messages. This method to stop the spread of COVID-19 works best when a close contact is placed under quarantine as soon after the exposure as possible.
Information shared with the contact tracing team is confidential. We do leave messages and there is a way to call us back or we will keep trying. If you are called by a contact tracer, the phone number will come up as an MTU number with a 487 prefix.
Why Does the Science Keep Changing?
Q: Unfortunately, a lot of people are mistrustful of scientists and medical researchers right now. There's a lot of misinformation out there. Why do medical and scientific guidelines keep changing?
KK: This is a brand-new disease, so everything we are learning is new. We are working to understand not only the virus itself, but also what public health measures work and don't work.
This is a coronavirus and scientists based a lot of the early information on SARS and MERS [coronaviruses that caused small outbreaks in 2003 and 2012, respectively], yet they are still very different viruses. We are continually refining and adjusting what we know as more data is available.
Q: To use a metaphor, coronaviruses could be compared to dog breeds. SARS-CoV-2 is a wolfhound, whereas MERS is a rottweiler. They're both dogs, but they're very different.
KK: Exactly. When you have something so new, you have to build up the scientific knowledge base. What's been said in the past that may be different now is not misinformation - it's that we've learned more. It makes it very hard to understand because advice does, necessarily so, change.
For example, I can't estimate how many contact tracers I need because I don't know how many contacts a college student might have. We can use the information as we learn it to build on in the future.
In this age of, "If I can't get it in two seconds, it's so slow," we must remember that science takes time. Public health is a science.
Q: How long do you think it will be until there's a vaccine?
KK: The shortest time to get a vaccine has been four years; the average is 10 to 15 years. The fact that we think we might have a vaccine in just a year is scientifically pretty amazing.
Scientists mapped the entire genome of the virus within a month from when it was identified. It's amazing to look at how much we do know about this virus in such a short period.
Michigan Technological University is a public research university, home to more than 7,000 students from 54 countries. Founded in 1885, the University offers more than 120 undergraduate and graduate degree programs in science and technology, engineering, forestry, business and economics, health professions, humanities, mathematics, and social sciences. Our campus in Michigan's Upper Peninsula overlooks the Keweenaw Waterway and is just a few miles from Lake Superior.
