(Reuters Health) – Patients may continue to shed the SARS-CoV-2 virus for up to six weeks after symptoms emerge, a small study of recovered COVID-19 patients suggests. One third tested positive 4 weeks after start of symptoms… so when can you go back to work after getting COVID?
Dr. Zhang and colleagues summarized their experience with 56 COVID-19 patients (median age 55; 61% men) admitted to Tongi Hospital in Wuhan in January and February. Throat or deep nasal cavity swab samples were collected on different dates after symptom onset. SARS-CoV-2 was diagnosed by real-time reverse transcription polymerase chain reaction (RT-PCR) assays All patients had mild-moderate infection.
As reported in Clinical Infectious Diseases, 299 RT-PCR assays were performed (about five tests per patient). The longest duration between symptom onset and an RT-PCR test was 42 days, whereas the median duration was 24 days.
In the first three weeks after symptom onset, the majority of RT-PCR results were positive for SARS-CoV-2. From week three onward, negative results increased. All tests were negative at week six after symptom onset.
The rate of positive results was highest at week one (100%), followed by 89.3%, 66.1%, 32.1%, 5.4% and 0% at weeks two, three, four, five and six, respectively.