Not long ago, Wang Guangfa, a member of the National Health and Health Commission’s Wuhan expert group and director of the Department of Respiratory and Critical Care Medicine at Peking University First Hospital, tweeted about his way of contracting the new coronavirus: he was highly suspected that the virus first entered the eye conjunctiva and then to the whole body. As soon as the news came out, many people worried that the new coronavirus could spread through the eyes, and goggles were once out of stock.
However, by analyzing 67 confirmed or suspected cases of new coronary pneumonia, the Chen Changzheng Research Group of Wuhan University People’s Hospital suggested that clinical data did not support the transmission of the new coronavirus through conjunctiva.
The paper was published on February 12th on the preprinted website medRxiv (Note: medRxiv papers are not peer-reviewed).
Can the new coronavirus infect a person by contacting the conjunctiva with aerosols? The reporter of China Science Daily interviewed three experts for proof.
Chen’s team analyzed 67 confirmed or suspected cases of new coronary pneumonia recorded from January 17 to 28, 2020.
Most of these cases were among health care workers, including 25 men and 42 women, with a median age of 35.7 years. As of 28 January, 63 patients had been diagnosed with neo-coronary pneumonia, while the remaining four were suspected of neo-coronary pneumonia.
The researchers found that in 67 cases, a conjunctiva swab sample in a patient with new coronary pneumonia gave positive PCR results, and two patients may have a positive PCR. However, none of the three patients had eye symptoms.
Only one patient with conjunctivitis as the first symptom of the new coronary pneumonia test for conjunctiva cystic 2019-nCoV was negative.
The conjunctiva swab samples for the four suspected cases of coronary pneumonia were negative.
Chen Changzheng research group in this regard, the incidence of conjunctivitis in patients with new coronary pneumonia is not high, clinical data do not support the new coronavirus can be transmitted through conjunctiva.
Is this conclusion true? Three experts interpreted it.
China Science Daily: Can the new coronavirus be transmitted through conjunctiva?
Li Shaowei, Ph.D. tutor of the Ayer Academy of Ophthalmology at Central South University and director of the Institute of Keratology of Eyre Ophthalmology:
The clinical observations of this article (the above study) are objective.
However, these observations can only show that at the time of the study, the new coronary pneumonia patients after the onset of the conjunctiva no obvious inflammation, no conjunctiva secretion, but can not explain whether these people through the conjunctiva infection, there is a possibility of infection after conjunctivitis self-healing.
Of course, at present, the main route of transmission of the new coronavirus or respiratory droplets, through the conjunctiva infection cases are rare, the probability may be relatively small, but there is no direct evidence that conjunctiva will not become a route of transmission, so can not rule out conjunctivation infection of the new coronavirus pneumonia.
Conjunctiva can infect many diseases, including H1N1 influenza virus, adenovirus, etc., there is scientific evidence.
For coronaviruses, such as during the SARS epidemic, who have also issued reports that do not rule out conjunctiva or tears being transmitted as bodily fluids.
However, scientists in Hong Kong, China, tested for the virus in tear sand and conjunctiva epithelial cells, and did not detect the virus.
However, this possibility cannot be ruled out. Because the virus into tears or conjunctiva, there are certain conditions, perhaps when sampling tears just do not detoxify.
Moreover, at that time, Hong Kong scientists tested too few samples, which required a large amount of experimental data to confirm.
China Science Daily: What is the mechanism by way of the spread of the virus through conjunctiva?
From the point of view of infection mechanism, it is necessary to judge whether there are specific binding protein sites in the epithelial cells of the conjunctiva sac in humans that bind to the new coronavirus.
We know that because the cell surface receptors in the human respiratory tract can bind specifically to viral binding proteins on the surface of the virus, the virus can then infect the human body from the respiratory tract.
Although the eye conjunctiva is similar to the nasal conjunctiva and respiratory conjunctiva, they are not exactly the same, so animal and in vitro experiments need to prove whether there are protein sites that are susceptible to infection and binding.
Guo Deyin, Dean of the Faculty of Medicine, Zhongshan University:
Conjunctiva sacs are connected to the nasal cavity through the nasal tear ducts, and the possibility of new coronaviruses re-infecting the respiratory tract through the eye conjunctiva is present, but more clinical evidence is needed to understand the efficiency and mechanism of infection through the eye conjunctiva.
China Science Daily: What is necessary to determine or deny the ability to spread the virus through a particular way?
Whether the conjunctiva can be infected is to be judged by animal experiments and in vitro experiments, through inoculation of the animal conjunctiva sac, to see if it can develop conjunctivitis, so as to the incidence of systemic infection.
There are few studies on infectious diseases such as SARS and MERS.
Perhaps because of the high rate of death from these viruses, scientists don’t have much energy to study whether they can be infected through conjunctiva, focusing on how to save lives and reduce mortality.
And this time the new coronavirus is highly contagious, low fatality rate, we see, many medical workers have also been infected, so, we are more concerned about the route of infection.
China Science Daily: What else are you concerned about about the possibility of conjunctiva infection?
In the future, scientists and doctors should continue to do some relevant scientific research, because the coronavirus is widely distributed, adult common cold, one of the main pathogens is coronavirus, we can not guarantee that the new coronavirus will no longer exist.
According to our experience, after a cold, especially after the infection of the respiratory system, there will be a certain proportion of viral conjunctivitis, but conjunctivitis is difficult to cause systemic complications.
Only a small number of people will have conjunctivitis-based symptoms, while having cold fever symptoms;
Although it is not clear whether the new coronavirus can be infected through the eye conjunctiva, it is necessary to take the necessary protective measures and effectively cut off the transmission route.
Because conjunctivitis can be caused by many pathogens. The Kosaki virus, for example, has been reported to cause outbreaks of hemorrhagic conjunctivitis.
Whether Professor Wang Guangfa’s conjunctivitis is caused by the coronavirus will require laboratory tests to determine.