Eye Infection with SARS-CoV-2 as a Route to Systemic Immunization?

Area of Science:

• Ophthalmology
• Virology
• Immunology

Background:

• Infectious diseases of the conjunctiva and cornea typically induce local and systemic immunity.
• Case reports suggest SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) conjunctivitis may confer systemic immunity, potentially offering a novel immunization route.
• This study investigates the immunogenicity of ocular SARS-CoV-2 infection.

Purpose of the Study:

• To determine if ocular infection with SARS-CoV-2 can induce systemic immunity in a hamster model.
• To assess the protective effect of ocular SARS-CoV-2 infection against subsequent respiratory challenge.

Main Methods:

• Twenty-four Syrian hamsters were divided into three groups: ocular SARS-CoV-2 infection (n=8), respiratory SARS-CoV-2 infection (n=8), and control (n=8).
• Animals were monitored for disease symptoms and weight changes.
• After two weeks, all animals were challenged via the respiratory tract to assess immunity.

Main Results:

• Ocularly infected hamsters showed minimal symptoms and only slight weight reduction, unlike the respiratory-infected group which experienced significant weight loss and lethargy.
• Following respiratory challenge, neither the ocularly nor the respiratory-infected groups showed signs of illness.
• Cytotoxic antibodies were detected in both infected groups, with higher titers in the ocularly infected animals.

Conclusions:

• Epi-ocular infection with SARS-CoV-2 induces systemic immunity with cytotoxic antibody formation without causing severe systemic illness.
• Ocular SARS-CoV-2 infection can protect against subsequent respiratory infection, suggesting a potential alternative immunization strategy.