Novel coronavirus (COVID-19) was found to be more effective than Severe Acute Respiratory Syndrome coronavirus (SARS-CoV) in infecting human airways and eyes, according to the faculty of Medicine of the University of Hong Kong that made the results public on Friday.

Michael Chan Chi-wai, associate professor of the university's School of Public Health, and his research team compared the infection of COVID-19, SARS-CoV and the influenza viruses such as H5N1 and H1N1 using human upper respiratory tract and eye tissues in a Biological Safety Level-3 laboratory.

The results showed that COVID-19 is much more efficient in infecting the human conjunctiva and the upper respiratory airways than SARS-CoV, and its level of infection is comparable to what is observed in the 2009 pandemic H1N1.

Taken together, this explains the higher transmissibility of the COVID-19 pandemic than that of SARS-CoV. "This study also highlights the fact that eyes may be an important route of SARS-CoV-2 (COVID-19) human infection," Chan said.

In a previous study, the research team discovered that COVID-19 can remain alive for a few days on smooth surfaces such as stainless steel, glass and plastic. The new finding highlighted the possibility that infectious virus can be spread from such contaminated surfaces by hands, when people touch the surfaces and rub their eyes afterwards.

The finding implicated that it is vital to avoid touching eyes when in public areas, and regular hand washing with soap and water or cleaning hands with alcohol hand rub as an essential measure to prevent accidental transfer of COVID-19 from contaminated surfaces to human eyes and noses.

The study has been published in medical journal the Lancet Respiratory Medicine.