Detecting SARS-CoV-2 RNA in conjunctival secretions: Is it a valuable diagnostic method of COVID-19?

The main purpose of this study is to evaluate the presence of viral RNA of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in conjunctival swab specimen of coronavirus disease 2019 (COVID-19) patients with and without conjunctivitis to establish the diagnostic value of reverse transcription-polymerase chain reaction (RT-PCR) in each case and to describe its clinical characteristics. A cross-sectional study was conducted at the Hospital Clinico San Carlos of Madrid, Spain. Thirty-six subjects from the COVID admission unit with laboratory-confirmed SARS-CoV-2 infection were included. Conjunctival swabs were collected from 18 patients with conjunctivitis and 18 patients without conjunctivitis and RT-PCR was performed. Conjunctival swab was collected from both eyes of 36 patients (72 eyes), detecting SARS-CoV-2 RNA in conjunctival swab of two patients (5.5%). Among the 18 patients with conjunctivitis, only one of them (5.5%) showed positive results. Likewise, SARS-CoV-2 RNA was detected in one patient without conjunctivitis (5.5%). The mean age of the 36 patients was 67.9 years (range, 28-92 years) and the male-to-female ratio was 0.44 (16:20). The mean days since the onset of COVID-19 symptoms until conjunctivitis manifestation was 8 (range, 1-24 days). The mean duration of the conjunctivitis was 3 days (range, 1-7 days). SARS-CoV-2 RNA may be detected in conjunctival swabs of both patients with and without conjunctivitis. This study revealed the same rate of positive results amongst the group with and without conjunctivitis, suggesting that detecting SARS-CoV-2 in ocular fluids is not conditioned on the presence of conjunctivitis. The presence of SARS-CoV-2 RNA in ocular samples highlights the role of the eye as a possible route of transmission of the disease.