Study: Asymptomatic COVID-19 patients may have left viral material on surfaces of exam room

The coronavirus disease 2019 (COVID-19) pandemic puts healthcare workers, including ophthalmologists, on the front lines of the battle against the virus.

Hasan Aytoğan, MD, of İzmir Tepecik Training and Research Hospital in Turkey, reported on research in which the coronavirus was detected on a small number of environmental samples from an exam room where asymptomatic patients underwent a routine ophthalmology exam.

The infectivity of the virus samples was not known. The investigators also note that there is little objective data that demonstrate the risks of encountering individuals carrying the virus asymptomatically in the case of maintained elective examinations.

The quality-improvement study was performed on Mar 20, 1 week after the first confirmed COVID-19 case was identified at Tepecik Training and Research Hospital in Izmir, Turkey.

According to the study, initially reported in JAMA Ophthalmology, of the seven samples taken after examinations of patients who passed COVID-19 triage questions, two samples of seven—one from the slit lamp breath shield and one from the phoropter—tested positive for coronavirus, according to Aytoğan’s team.

Aytoğan noted that RT-PCR cannot determine the presence of infectious virus and that the testing method has limitations.

They examined two threads of research to conduct their study: how long the virus lasts on surfaces, as well as the role of asymptomatic transmission by looking at an examination day in an outpatient ophthalmology clinic “without interventions for patients who were asymptomatic.”

“Since we were examining patients who are asymptomatic during the pandemic, we wanted to know if we could detect COVID-19 viral material at the end of a day of examinations of patients who were asymptomatic and seen in an eye examination room,” investigators wrote.

Contamination from the preceding days was ruled out, considering that all samples that were taken before examinations had negative results for viral material. Two of the 3 samples that were taken from the slitlamp shield and phoropter in zone 1 after examinations had positive results.

The room was cleaned with a hydrogen peroxide solution and had no visitors for 18 hours after cleaning.

Importantly, the authors noted the room was not cleaned between patients, but chin and forehead rests were wiped with isopropyl alcohol, 70%.

“The same physician performed all examinations, and 1 health care worker visited the room during examinations,” the investigators wrote. “Only companions of patients of pediatric age and patients with communication and mobility problems were allowed to enter the room. The numbers of companions were recorded.”

Researchers used real-time polymerase chain reaction (RT-PCR) testing to detect viral RNA in samples from the biomicroscope stage, slit lamp breath shield, phoropter, tonometer, and door handles. In a recent study, the total positive rate of PCR was reported as 30% to 60% at the initial presentation.¹

REFERENCES
1. Yang Y, Yang M, Shen C, et al. Evaluating the accuracy of different respiratory specimens in the laboratory diagnosis and monitoring the viral shedding of 2019-nCoV infections. Published February 17, 2020. Accessed July 24, 2020. https://www.medrxiv.org/content/10.1101/2020.02.11.20021493v2