Question: My son had a contact with a boy (band mate, practicing in an open garage for about 20min on Thursday) who got a positive test the day after. We are currently keeping my son isolated. Four questions: 1) Should he get tested or should he just be quarantined for two weeks? 2) If we can reduce the length of quarantine based on a test result, when is the optimal time for my son to be tested?; 3) There was about a 48 hour window between my son’s contact with the boy and the self-quarantine (Thursday and Saturday). We, the rest of the family, wonder if he might have become contagious and thus we were also exposed and need to be quarantined. Should we? 4) If so, when is the optimal time for us to get tested? We are self-quarantined for now. Ugh…

Answer: I’m sorry, that all sounds quite stressful. First off, it’s important to assess whether your son meets the criteria of “close contact” — any individual within 6 feet of an infected person for a total of 15 minutes or more. Based on your description, it sounds like the answer is yes. In which case, you’re doing the right thing by having him self-quarantine. Now let’s turn to your specific questions:

1. Should he get tested?: Yes, your son should get tested. CDC recommends testing for all “close contacts” of confirmed positive individuals. (Figure 1)

2. Can we reduce the length of quarantine based on a negative test result?: No, you cannot reduce the duration of self-quarantine based on a negative test result. Because the COVID-19 incubation period ranges from 2–14 days (median 5 days), a negative test result before the end of the 14-day quarantine period does not rule out possible infection.

3. Should we consider ourselves exposed?: There’s not a straightforward answer. We know that people are very contagious 24–48 hours before they develop symptoms. And we know that it takes some time after exposure for a person to begin shedding the virus themselves. We don’t know how long that window is between exposure and viral shedding is, especially because it seems to vary from person to person. If most symptoms begin around day 5 and people are highly contagious 48 hours beforehand, we can surmise that individuals may become very contagious at day 3. Since it also takes time for the virus to replicate and viral shedding to begin, we can surmise that the risk of being contagious at day 1 is exceedingly low. Day 2 of exposure is murkier. However, you and your family were not necessarily directly exposed! Rather, you were with your son, who was exposed, but not necessarily infected. This is another reason why it’s so important for your son to get tested. If his test comes back positive, you know to consider yourselves exposed and to self-quarantine. If his test comes back negative, it’s again murky. It’s possible to get a negative result and still be contagious. As Johns Hopkins professor, Dr. Justin Lessler, told CNN earlier this week, “The virus just takes time to replicate in the body to detectable levels. You can get infected by just a few viral particles, but these will not be detectable until they have time to replicate to adequate levels to be detected.” If you and your family can do it, it’s probably the most prudent to self-quarantine.

4. When is the optimal time to get tested?: Testing seems to be most accurate when done at either a) symptom onset OR b) 4–5 days after exposure (see Q&A of 10/22 #Testing)

If you want more information, the Virginia Department of Health’s website on COVID exposure and MIT page on COVID exposure and are both informative and easy to read.

Figure 1. Summary of Recommendations for Close Contacts (from CDC)