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Infectious Diseases

Updated 31 March 2020

Coronavirus transmission: Chance of spreading through tears is very low

As fears over the deadly virus continue, a new study confirms risk of transmission via tears is very low.

The new coronavirus has been identified as more infectious than the 2003 SARS virus due to the rapid rate at which it is spreading around the world.

The virus can spread through droplets expelled by coughing and sneezing, direct contact and by coming into contact with contaminated surfaces and objects, explains the World Health Organization (WHO). And more recent research has sparked curiosity around another way the virus might spread: through tears.

However, research published in the journal of the American Academy of Ophthalmology (AAO) this week confirms that there is a very slim chance that infected patients are passing on the virus through tears.

The paper, titled Assessing Viral Shedding and Infectivity of Tears in Coronavirus Disease 2019 (COVID-19) Patients involved eight researchers from the National University Hospital in Singapore who collected tear samples from 17 patients with Covid-19. 

Traces in eye secretions

The samples were taken from the time the patients displayed symptoms until their recovery – about 20 days later. Their research indicates that a total of 64 samples were collected over the study period (around three weeks).

Samples were also taken from the patients’ back of the nose and throat during this period, and the overall results showed that while all patients’ tears were clear of the virus, it was, in fact, detected in the nasal and throat swabs.

The team explained that the results "suggest that transmission through tears regardless of the phase of infection is likely to be low", although they added that further research is needed into the virus transmission.

A small-scale Chinese study carried out in February found that one of 30 patients who had Covid-19 was found to have conjunctivitis, also known as pink eye.

The researchers also found traces of the virus in the patient’s eye secretions. However, a news release by the AAO explained that infection of the virus through tears is highly unlikely. 

How long can coronavirus survive on surfaces?

Although there is clarification around the transmission of the virus, it is not yet entirely certain how long it can survive on surfaces, notes the WHO, adding that it seems to behave like other coronaviruses.

This means it may persist on surfaces of a couple of hours, or up to several days. This all depends on the conditions, such as the type of surface and the temperature of the environment.

As a precautionary measure, you should clean surfaces with a disinfectant, and ensure you wash your hands thoroughly with soap and water or use hand sanitiser with an alcohol content of 60% or higher. Also, avoid touching your face as your mouth and nose are key gateways for the virus to enter your body. 

*As of 30 March 2020, there are over 1 200 confirmed cases of coronavirus and two deaths in South Africa. Find all the updates here.

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Image: Aliyah Jamous, Unsplash