While scientists assumed that the coronavirus (COVID-19) was mostly found in the nasal passages, a new report in the journal Annals of Internal Medicine indicates that it survives much longer in the eyes. The report detailed that a Chinese woman, who had continued to carry the virus in her eye despite it no longer being found in her nose.
The 65-year-old woman flew from Wuhan, where the pandemic first broke out, to Italy on Jan. 23. She reported feeling sick on Jan. 27 and was later hospitalized at the National Institute for Infectious Diseases (INMI) Lazzaro Spallanzani in Rome on Jan. 29, where she was confirmed as the country’s first case of the coronavirus.
During this time, she developed a cough, high fever and, more importantly, an eye infection. The latter persisted longer than expected, which prompted medical staff to take swabs from her eyes for testing. Tests confirmed that the eye infection was due to the coronavirus, after which the woman continued to receive eye swabs throughout her stay. (Related: Viral pink eye seen in both symptomatic and asymptomatic coronavirus cases, making it a possible sign of infection.)
“We found that ocular fluids from SARS-CoV-2-infected patients may contain infectious virus, and hence may be a potential source of infection,” wrote the report’s authors.
Eventually, her eye infection cleared, and medical staff no longer found traces of the virus after 20 days. However, seven days after that, the virus reappeared in her eyes.
Further tests on ocular and nasal swabs on the patient showed that the virus seemed to persist longer in the eyes than in the nose. Traces of viral RNA continued to be found in the ocular swabs long after they could no longer be found in nasal swabs.
“SARS-CoV-2 RNA was detected in ocular swabs days after it was undetectable in nasal swabs,” the report stated.
To check whether what they found was the actual coronavirus and not just dead particles of it, the researchers checked if the sample could still infect other cells. These tests demonstrated that what was in the eyes was indeed the virus and could infect other people.
According to the report, the presence of the coronavirus in the eyes, and the risk of it being transferred through ocular fluids, highlight the importance of measures to stop the spread of the virus.
“These findings highlight the importance of control measures, such as avoiding touching the nose, mouth, and eyes and frequent hand washing,” the authors stated.
In particular, personal protective equipment for ophthalmologists is now more important with proof that ocular fluids can be a vector for the spread of the disease.
More importantly, the report notes that the coronavirus can be found in the eyes even during the early stages of the infection. With this in mind, measures to prevent the spread of the virus through the eyes and ocular fluid need to be implemented as early as possible.
Beyond these recommendations, however, the report notes that there are still things that are not known about how the coronavirus survives in the eyes. Specifically, the authors state that further study is needed to identify the kinds of human ocular cells that are able to support viral replication and to identify the mechanisms that underly the ocular tropism of the coronavirus.