Implementation of COVID-19 safety measures leads to fewer infectious conjunctivitis cases

Investigators assessed the impact of COVID-19–associated public health measures on the epidemiology of infectious conjunctivitis by evaluating searches on the internet and reviewing visits to the emergency department (ED) at a single academic hospital in the United States.

Study design

The investigators looked at internet search trends for the following terms: nonallergic conjunctivitis, corneal abrasions, and posterior vitreous detachments (PVDs). Data were compared from before and after April 2020, when the Centers for Disease Control and Prevention first recommended COVID-19 mitigation measures, including mask wearing, social distancing, and quarantining, for symptomatic individuals or those exposed to individuals with COVID-19 symptoms. Six-year electronic health record data were reviewed for all instances of conjunctivitis seen in the ED (except for allergic conjunctivitis).

Outcomes

In the timespan studied, there were 1156 ED visits with a diagnosis of conjunctivitis. After the widespread adoption of public health measures to mitigate COVID-19, there was a 34% decrease in internet search interest for terms related to conjunctivitis, and a 37% decrease in ED visits for nonallergic conjunctivitis. The reduction in nonallergic conjunctivitis diagnoses is contrasted with a stable number of ED visits for corneal abrasion and PVDs.

Limitations

The investigators could not independently ascertain if the decrease in infectious conjunctivitis encounters in the ED was solely due to an actual decrease in the number of cases or if the patients were also less likely to present to an ED due to concerns about contracting COVID-19. However, when they controlled for the total number of ED encounters, they noticed a decrease in the number of conjunctivitis-associated visits, while the number of ED visits for corneal abrasions or PVDs remained stable. The investigators could not attribute the associations they found to any one particular infectious pathogen and could not exclude all noninfectious cases of conjunctivitis.

Clinical significance

This is the first report demonstrating a sustained population-wide decline in the rate of infectious conjunctivitis cases presenting to EDs. As the decrease was coincident with the public health measures to mitigate COVID-19, these measures may have played a role in the national infectious conjunctivitis decline. Simultaneously, this decrease correlated with a reduced search interest in nonallergic conjunctivitis. Search metrics combined with mobility data may yield quantifiable metrics of the effects of public health initiatives and a means of surveillance of infectious conjunctivitis.