Are respiratory diseases easily contagious?

The answer is that most common respiratory diseases are indeed highly contagious, but the risk of infection cannot be generalized and must be comprehensively judged based on the type of pathogen, the scene in which it is located, and the protective measures.

After all, respiratory diseases are mostly transmitted through droplets and aerosols, which are the two most trouble-free routes. Think about it, the small droplets ejected from someone sneezing or speaking loudly around you can almost hit your face directly within a range of more than 1 meter. If you are in a closed space such as a conference room or elevator without opening windows, the lighter aerosol can float like small dust for dozens of minutes, and anyone passing by may be infected. You must have seen half of a class in school during the flu season. During the COVID-19 epidemic two years ago, many people were infected just by riding in the same subway car. This is why.

Don’t think that just by mentioning the words “respiratory disease”, it’s easy to spread the disease. In fact, the infectivity of many types is very low, or even almost non-transmissible from person to person. For example, we often talk about common bacterial pneumonia, such as community-acquired pneumonia caused by Streptococcus pneumoniae and Klebsiella pneumoniae. As long as your immunity is normal, you will rarely be infected even if you eat or talk with the patient on a daily basis. ； There are also fungal respiratory diseases such as pulmonary aspergillosis, which can only be contracted by people with immune deficiencies such as those who have been taking hormones for a long time or AIDS. Ordinary people will not get sick even if they are exposed to pathogens.

Let me tell you a true story that I encountered in the outpatient clinic last month. A family of three came to see the doctor last month. The father first contracted influenza A and had a fever of over 39 degrees. When taking care of the mother at home, the mother wore a surgical mask at all times and opened the window for ventilation every day. The 5-year-old child felt bored and refused to wear it. You see, even with influenza, which is recognized to be highly contagious, taking good protection can keep the risk of infection very low.

So you don’t need to panic when you hear someone around you has respiratory disease. Ask first what type it is, wear a mask, and open more windows. Most situations can be prevented.