Detection of SARS-CoV-2 in conjunctival secretions from patients without ocular symptoms

Li, Xin; Chan, Jasper Fuk-Woo; Li, Kenneth Kai-Wang; Tso, Eugene Yuk-Keung; Yip, Cyril Chik-Yan; Sridhar, Siddharth; Chung, Tom Wai-Hin; Chiu, Kelvin Hei-Yeung; Hung, Derek Ling-Lung; Wu, Alan Ka-Lun; Chau, Sandy Ka-Yee; Liu, Raymond; Lung, Kwok-Cheung; Tam, Anthony Raymond; Cheng, Vincent Chi-Chung; To, Kelvin Kai-Wang; Chan, Kwok-Hung; Hung, Ivan Fan-Ngai; Yuen, Kwok-Yung

PURPOSE: To evaluate the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in conjunctival secretions from patients without ocular symptoms. METHODS: Conjunctival swabs were prospectively collected from laboratory-confirmed Coronavirus disease 2019 (COVID-19) patients without ocular symptoms for reverse transcription-polymerase chain reaction (RT-PCR) and viral culture. RESULTS: A total of 158 conjunctival swabs were obtained from 49 laboratory-confirmed COVID-19 patients. The median duration of illness when the first conjunctival swab was obtained was 10 days (range 2–27 days). Four conjunctival swabs from four different patients (4/49, 8.2%) were positive for SARS-CoV-2 RNA by RT-PCR. The Ct values ranged from 32.7 to 37.7 (mean 35.4). Viral cultures were negative for all four RT-PCR-positive conjunctival swabs. CONCLUSION: Conjunctival secretions of a minority of COVID-19 patients without ocular symptoms may contain relatively low levels of SARS-CoV-2 RNA, but their infectiousness remains undetermined. Appropriate infection control measures should be implemented during ophthalmological assessment of COVID-19 patients to prevent potential nosocomial transmission of SARS-CoV-2.