Conjunctival conveyance of SARS-CoV-2 in asymptomatic and non-severe symptomatic COVID-19 patients

INTRODUCTION: The prevalence of ocular conveyance of SARS-CoV-2 has been well described for severe/hospitalized cases, but scarcely reported in asymptomatic and non-severe patients, who are unaware that they are carriers. MATERIAL & METHODS: This prospective cross-sectional study quantitatively evaluated SARS-CoV-2 shedding on the ocular surface (OS). Conjunctival testing was suggested to all hospital personnel being screened by nasopharyngeal (NP) SARS-CoV-2 reverse transcription polymerase chain reaction (RT-PCR). Disease symptoms were evaluated using a standardized questionnaire and telephone follow-up 6 ± 3 months later for disease evolution (recovery with/without severe disease). RESULTS: Four hundred and eighty seven patients were included. From 46 NP SARS-CoV-2-positive subjects (cycle threshold [CT] = 24.2 ± 7.1), 13% tested positive at the OS (CT = 36.4 ± 2.8). Most SARS-CoV-2-positive subjects were symptomatic (n = 40, 87%), while 6 were asymptomatic (being tested as contact cases). Systemic symptoms were not significantly different in OS-positive vs OS-negative subjects, although headache tended to be more frequent in OS-positives (83% vs 54%, P = 0.06). None of the OS-positive subjects reported ocular symptoms and none developed severe disease requiring hospitalization or oxygen therapy. CONCLUSION: SARS-CoV-2 shedding at the OS may occur in asymptomatic and non-severe COVID-19 individuals (including those absent of ocular symptoms). However, the high RT-PCR CT values attained may indicate a low risk of transmissibility via this route.