New-onset conjunctivitis 3.5 years post SARS-CoV-2 infection in an inner-city population in the Bronx.

Background: A few studies have reported conjunctivitis is a complication associated with acute COVID-19. It is unknown whether SARS-CoV-2 infection increases the risk of conjunctivitis post-COVID-19 long term.

Objectives: This study investigated the incidence of new-onset conjunctivitis 3.5 years post SARS-CoV-2 infection and compared it with patients without SARS-CoV-2 infection.

Methods: This retrospective study consisted of 67 702 patients who tested positive for COVID-19 (defined by a positive PCR test), and 1 391 135 COVID-19-negative patients with no prior records of conjunctivitis in the Montefiore Health System from 11 March 2020 to 31 December 2022. The study included adult patients re-presenting to our centre with conjunctivitis. Outcome was new conjunctivitis between 14 days and 3.5 years post index date. Analysis was performed with unmatched and matched cohorts. Matching was done for age, sex, race and ethnicity. Cumulative incidence and hazard ratio (HR) with and without adjustment for competitive risks were analysed.

Results: There were 1154 (2.27%) individuals with COVID-19 and contemporary 13 899 (1.57%) controls who developed new conjunctivitis. COVID-19-positive patients had a significantly higher risk of developing new incident conjunctivitis (unmatched cohort adjusted HR 1.11 (95% CI 1.04 to 1.17), matched cohort adjusted HR 1.10 (95% CI 1.02 to 1.16)) compared with COVID-19-negative patients.

Conclusions: COVID-19-positive patients had significantly higher risk of developing new conjunctivitis compared with contemporary COVID-19-negative controls. Identifying risk factors for developing new-onset conjunctivitis may draw clinical attention for careful follow-up in at-risk individuals for ocular infections.