Bragging about catching a cold comes true?
I once boasted to my friends that I had in-depth research on infections and that there was probably no one in the country who knew colds better than me.
For example, you can go to any county hospital and gather all the doctors together and ask them, "What is a cold?" I'm afraid no one can answer this question accurately.
Today, a friend asked me a question, which made me feel that the quality of my cold cowhide is really insufficient.
Because the "popular science" about colds by well-known experts across the country completely overturned my most basic understanding of colds.
Experts: Colds are caused by viruses that "colonize" the human body and are not contagious. A friend said that today I accidentally came across a popular science video about the differences between colds, influenza and the new coronavirus. A doctor from Peking Union Medical College Hospital said that colds are caused by viruses that "colonize" the human body and are not contagious.
"Colds are contagious" is a simple fact known to everyone. How do experts say that colds are not contagious?
Who should I trust? A simple search of
shows that this statement has only been circulating on the Internet recently, and it has spread very widely.
The "popular science" of this doctor from Union Hospital seems to be "picked up" through , Baidu and .
Tracing the origin, we found that this statement most likely first appeared on November 5, 2022, at the press conference of the Joint Prevention and Control Mechanism of the State Council, by Professor Wang Guiqiang, Director of the Department of Infectious Diseases at Peking University First Hospital, when he introduced the differences between COVID-19, colds and influenza.
You can also find the video and written transcript of the press conference on the Chinese government website.
The original text that Professor Wang said at the time was:
"First of all, from the pathogenic point of view. The common cold is caused by some viruses colonized by , such as rhinovirus ; influenza is caused by influenza viruses; the new coronavirus is the new coronavirus. Second, from the perspective of infectivity. Colds are not contagious , when resistance htm When L6 drops, some viruses colonizing the upper respiratory tract may replicate and cause symptoms. ... Judging from the season of occurrence. Colds are not seasonal. They can occur all year round. Because resistance decreases, local virus reproduction can cause symptoms... "
This...
What is a cold?
WHO named the new coronavirus as COVID-19. This word "Disease" is not just called casually. It is strictly defined in medicine.
"a Disease" means a structural and functional disorder with a known cause and a defined group of symptoms, signs, and anatomical changes.
COVID-19 and influenza are both diseases with relatively clear cognition.
The cold is different. It is not a disease, but a (mild) "syndrome" manifested by upper respiratory tract infection caused by many kinds (more than 200 kinds) of viruses.
In other words, as long as more than 200 viruses classified in the cold virus sequence cause upper respiratory tract infections and show typical symptoms such as sneezing, runny nose, nasal congestion, rhinorrhea, and sore or itchy throat, they can be classified as colds.
Cold pathogens
Cold pathogens include more than 200 viruses (not including any bacteria , bacterial infections are not colds).
Among them, the most common one is rhinovirus, with more than 100 known serotypes. 30% to 50% of colds in adults are caused by rhinovirus infection.
Next are the four human (old) coronaviruses that are close relatives of the new coronavirus, causing about 10% to 15% of colds.
Other cold viruses include respiratory syncytial virus , adenovirus , influenza virus, parainfluenza virus, echovirus and coxsackie virus, two types of enterovirus, cytomegalovirus , human metapneumovirus, etc.
Are cold viruses all "colonization" viruses in the human upper respiratory tract?
all None of these cold viruses are so-called human "colonization" viruses.
The concept of "colonization" mainly refers to bacteria that can exist for a long time in specific parts of the organism, because bacteria are microorganisms that can survive independently under certain environmental conditions.
Viruses are different. Since they cannot leave the host cell and replicate independently, they cannot survive independently as long as they do not infect cells.
Therefore, the so-called "colonization" phenomenon of viruses rarely occurs.
The only virus that can colonize the upper respiratory tract of the human body seems to be the herpes simplex virus, which is the virus that causes blisters at the corners of the mouth when some people get angry.
This virus can infect human cells, but the infected person will have obvious symptoms during the refractory period. Under certain conditions, the infection may worsen and cause herpes around the mouth.
None of the more than 200 cold viruses are so-called "colonization" viruses.
Colds are highly contagious.
None of the more than 200 cold viruses are so-called "colonization" viruses. Human colds are all transmitted through person-to-person transmission, so colds are highly contagious.
Since there are many types of cold viruses, each virus has a different R0 (representing the basic reproduction coefficient of infectivity), so the infectivity of colds caused by different viruses is not the same.
Research has known that the transmission route of colds is almost the same as that of influenza and COVID-19, mainly including aerosol transmission , respiratory direct transmission, and indirect transmission through object surfaces, hands, mouth and eyes.
It is generally believed that the latter’s indirect contact transmission contributes more to the spread of colds than influenza and COVID-19. Therefore, regular hand washing plays a more important role in preventing colds.
Of course, different cold viruses spread in different ways.
For example, aerosol transmission is an effective transmission route for influenza viruses and coronaviruses, but not for respiratory syncytial virus infection ; rhinovirus is most likely to be transmitted through large droplets or direct transmission.
All colds have a certain seasonality
Although there are many types of viruses that cause colds, almost all colds have a certain seasonality.
Taking the temperate climate of the northern hemisphere as an example, it can be predicted that the cold epidemic season will start in September and last until the following spring.
This persistent epidemic curve of colds is the result of the continuous spread of different cold viruses in the community.
Specifically, rhinovirus infections begin to increase sharply in September each year, the season after children return to school;
followed by parainfluenza viruses in October and November;
respiratory syncytial virus and
coronavirus shows a high degree of winter epidemic characteristics ;
colds caused by influenza viruses peak in late winter;
then rhinovirus once again has a small epidemic peak and ends the epidemic of colds throughout the year;
in the summer months, rhinoviruses and enteroviruses are mainly distributed.
It can be seen that most of Professor Wang’s introduction about colds is very wrong.
However, this error has been widely spread because it was released on high-level occasions such as the press conference of the Joint Prevention and Control Mechanism of the State Council. Even doctors from Union Medical College Hospital copied it to "popularize science". This shows that careless "science popularization" in medicine can cause huge harm.
