SARS-CoV-2 in conjunctival swabs: Possibility of a delayed or a prolonged shedding on ocular surface than in nasopharyngeal secretions
Purpose
The detection rate of SARS-CoV-2 in conjunctival swabs of COVID-19 patients is variable, and its viral RNA load is unknown compared to nasopharyngeal swabs.
Methods
Conjunctival swabs of COVID-19 patients (with PCR-positive nasopharyngeal swabs) were subjected to quantitative reverse-transcription polymerase chain reaction (RT-PCR) for detection of SARS-CoV-2 RNA. The cycle threshold (Ct) values of Open Reading Frame 1 (ORF 1 Ab gene) and nucleoprotein (N gene) PCRs were used to assess the viral RNA load.
Results
: Of 93 patients, 17 (18.27%) demonstrated SARS-CoV-2 RNA in conjunctival swabs. Baseline nasopharyngeal swabs (data available in 79 patients) were collected at a median of 2 days, followed by conjunctival swab collection (93 patients) at median 7 days, from onset of illness (p < 0.001). In ‘conjunctival swab positive’ patients, the Ct values (ORF or N gene PCRs) were comparable between baseline nasopharyngeal and conjunctival swabs, despite a significant delay in conjunctival swab collection compared to nasopharyngeal swab collection.
Conclusion
The conjunctival swabs demonstrated SARS-CoV-2 RNA in 17 (18.27%) of 93 COVID-19 patients. In four of these 17 patients during the recovery period, when the second nasopharyngeal swab was ‘negative’, the conjunctival swab was ‘positive’. Our results may suggest a delayed or a prolonged shedding of the virus/viral RNA on the ocular surface than in nasopharyngeal mucosa.
Conflict of interest
No
Authors 1
Last name
BANSAL
Initials of first name(s)
R
Department
Ophthalmology, PGIMER
City
Chandigarh
Country
India
Authors 2
Last name
Bora
Initials of first name(s)
I
Department
Virology, PGIMER
City
Chandigarh
Country
India
Authors 3
Last name
Kanta
Initials of first name(s)
P
Department
Virology, PGIMER
City
Chandigarh
Country
India
Authors 4
Last name
Singh
Initials of first name(s)
M P
Department
Virology, PGIMER
City
Chandigarh
Country
India
Authors 5
Last name
Bhalla
Initials of first name(s)
A
Department
Medicine, PGIMER
City
Chandigarh
Country
India
Authors 6
Last name
Gupta
Initials of first name(s)
V
Department
Ophthalmology, PGIMER
City
Chandigarh
Country
India
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