- As many as 1 in 5 people who test positive for SARS-CoV-2 is asymptomatic but has nasopharynx viral loads comparable to patients with mild symptoms.
- Mildly symptomatic and asymptomatic individuals demonstrate persistent positive upper respiratory reverse transcription (RT)-PCR findings at follow-up.
Why this matters
- Although more data are needed, asymptomatic patients might be community superspreaders.
- Patients who test positive for SARS-CoV-2 but present with no or mild symptoms may need to take extra preventative precautions, especially to minimize household transmission.
- Of the 183 out of 213 patients included in the follow-up analyses, the median age (interquartile range) was 25.0 (21.5-34.0) for those who were asymptomatic and 26.5 (22.0-46.0) for those with symptoms.
- Of the 183 who had follow-up RT-PCR data, 39 were asymptomatic and 144 had symptoms.
- On follow-up:
- 54% (n=21) of asymptomatic patients tested positive for virus gene sequences.
- 64% (n=92) of symptomatic patients tested positive (P=.25).
- Mean cycle threshold (Ct) values for specific sequences between asymptomatic and symptomatic patients:
- E gene: 31.15 vs 31.43 (P>.99).
- RdRp gene: 32.26 vs 32.93 (P=.92).
- N gene: 33.05 vs 33.28 (P>.099).
- Retrospective cohort analysis, Korea.
- Funding: Korea Health Industry Development Institute.
- Young participants, single country; limited generalizability.
- Recall bias.
- Initial RT-PCR test results missing.
- Time-related, follow-up testing bias.