One of the frequently asked questions of me about this thing is “How long am I contagious after I recover?” which is often followed up by “Do I continue to shed the virus even after testing negative?” Indeed, these questions are interesting and answers to them seem to evolve through time as we get more anecdotal reports and even based on few experimental observations. In the gist of these questions are two seemingly similar concepts albeit with some stark difference. There doesn’t seem to be a direct link between viral shedding and infectiousness.
Cheung, et al on April 3, 2020 published an analysis of data from the Hong Kong cohort of patients with C-19 and a meta-analysis of findings from other publications wherein they found that 17.6% of patients with C-19 had gastrointestinal symptoms. They also found that SARS-CoV-2 RNA was detected in stool samples from 48.1% patients-even in stool collected after respiratory samples tested negative and even up to 33 days after onset of the illness
What is not really known based on that data is if these were only RNA fragments or active virus particles that could infect someone.
Circling back to the questions from above, US CDC has issued guidelines on discontinuing the use of PPEs for HCWs taking care of recovering or fully recovered C-19 patients. They recommend either one of two things for guidance. The first one is clinical or non test based which I simplify to 7-3-0 (I am the mnemonic master in med school). It should have been 7 days or more after the onset of symptoms; absence of fever for 3 days or more without need for antipyretics; zero respiratory symptoms. The second method is test based approach that calls for 2 negative swabs 24 hours apart.
Glad to confuse you further.