Detection of SARS-CoV-2 RNA in a conjunctival swab sample in real-time-polymerase chain reaction positive COVID-19 patients and its association with comorbidity and severity at a designated COVID-19 hospital in Central India

Abstract

Purpose: To evaluate the presence of SARS-CoV-2 RNA in the conjunctival swab sample of positive confirmed COVID-19 patients and to find out its association with comorbidity and severity of COVID-19 disease. Methods: We conducted an observational cross-sectional study at a dedicated tertiary COVID-19 hospital in central India for a period of 8 weeks from February 2021to March 2021. We included patients who tested positive for SARS-CoV-2 RNA through nasopharyngeal swab and were above 18 years of age. Swab samples have been collected within 48 h of admission. Conjunctival swab was taken from the lower fornix of both eyes and sent to microbiology laboratory for real-time- polymerase chain reaction (RT-PCR). Results: Out of 150 patients, conjunctival swab RT-PCR was positive in five patients (3.33%). Two patients had conjunctival manifestations in the form of conjunctivitis but conjunctival swab RT-PCR was negative in those patients. Among the RT-PCR positive patients, two (40%) were from mild, one (20%) was from moderate, and two (40%) were from severe category. No association could be established between conjunctival swab RT-PCR positivity and severity of the disease or associated comorbidity. Conclusion: Our study provides evidence that SARS-CoV-2 RNA could be detected in conjunctival secretions, and though the risk is relatively low, the eye may act as source of transmission. Extra caution should be taken by healthcare workers, and use of proper precautions like face shields and goggles should be encouraged.

SARS-CoV-2 infects cells lining the blood-retinal barrier and induces a hyperinflammatory immune response in the retina via systemic exposure

“…The ocular mucosal milieu has been identified as the most susceptible region that can be affected by transmissible microorganisms, including viral and bacterial pathogens such as herpes simplex virus-1, influenza, Zika, and Staphylococcus aureus [ 16 , 28 , 47 – 51 ]. Previous studies have shown the presence of SARS-CoV-2 RNA and proteins in various ocular tissues and fluids, including conjunctiva, limbus, tears, and aqueous humor, indicating that the eye could be a potential site of infection and transmission [ 21 , 25 , 38 ]. It is believed that SARS-CoV-2 can be disseminated through the ocular surface via nasolacrimal ducts, which connect the ocular surface with the respiratory tract, facilitate aqueous exchange, and provide shared lymphoid tissues between these sites [ 50 , 51 ].…”

“…The overall prevalence of ocular manifestations among COVID-19 patients has been shown to be 11.03% [ 17 ] and even higher (42.8%) amongst juveniles [ 18 ]. Although many studies have demonstrated the expression of SARS-CoV-2 binding receptors, angiotensin-converting enzyme 2 (ACE2) and a transmembrane serine protease, TMPRSS2, on ocular surfaces [ 19 , 20 ] and the presence of viral RNA in conjunctival swabs [ 21 , 22 ], tears [ 23 , 24 ], and aqueous humor [ 25 ], the possible ocular transmission, tropism, pathology, and long-term effect of COVID-19 on eye remains inconclusive. Moreover, patients with comorbidities such as diabetes have demonstrated increased SARS-CoV-2 morbidity and severity.…”

Manifestations of coronavirus infection disease-19 in anterior eye segment: An up-to-date review

“…[ 56 ] Furthermore, several studies showed the existence of SARS-CoV2 in the conjunctival discharges and tears, which are potential ways for spreading the virus into the nasopharynx or eye contact. [ 2 57 58 59 60 61 62 63 64 65 ] However, according to a recent systemic review, no-cut clinical evidence demonstrated that eyes are a transmission pathway for COVID-19. [ 2 ] Furthermore, the conjunctival sac is not a favorable place for SARS-CoV2 replication according to the findings of the conjunctival swabs of postmortem and alive patients.…”

Conjunctival Swabs Reveal Higher Detection Rate Compared to Schirmer Strips for SARS-CoV-2 RNA Detection in Tears of Hospitalized COVID-19 Patients

“…SARS-CoV-2 prevalence in tears has already been explored in other studies, ranging from 0% to 57% [ 27 , 28 ]. Most of these studies used only CS for tear collection [ 27 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ], one study used only SS [ 43 ], and four other studies used both tear collecting methods [ 44 , 45 , 46 , 47 ]. Our study confirms previous findings that CS samples had a higher SARS-CoV-2 detection rate compared to SS samples, and the viral loads in tear samples were lower compared to nasopharyngeal samples [ 44 , 45 , 46 , 47 ].…”