Are respiratory diseases contagious?

The answer is not black and white. Only respiratory diseases caused by contagious pathogens can be transmitted. Respiratory diseases that are non-infectious, or whose pathogens do not have the characteristics of human-to-human transmission, are not contagious at all.

The influenza, COVID-19, measles, tuberculosis, and the high incidence of Mycoplasma pneumoniae infection among children in recent years are all clearly contagious. Take last winter when the outpatient clinics were full. In many families, the eldest child got mycoplasma pneumonia first and had a fever and cough. The parents did not pay attention to isolation. Within two days, the second child also caught the fever. Even the adults taking care of the children had to cough for more than half a month. These pathogens are mainly spread by droplets expelled by patients when they cough and sneeze. Aerosols in confined spaces can also carry viruses. If you come into close contact without protection, the probability of getting infected is very high.

But not all respiratory problems are contagious. Not long ago, I met a young girl in her early twenties at the outpatient clinic. She cried sadly and said that she had suffered from allergic rhinitis for two weeks. Her colleagues in the office avoided her and did not even dare to accept the milk tea she handed her for fear of being infected with rhinitis. In fact, it is completely unnecessary. Allergic rhinitis, bronchial asthma, chronic obstructive pulmonary disease, and non-infectious pharyngitis caused by simple stimulation are not caused by infectious pathogens. No matter how hard the patient coughs or sneezes, they will not infect those around them.

Many people tend to confuse common colds with influenza. Common colds are mostly caused by weakly contagious pathogens such as rhinovirus and adenovirus. Only those who come into contact with them may be infected if their resistance is particularly weak. The contagiousness is far less than that of influenza, so there is no need to panic. There are also some elderly people with chronic bronchitis and chronic obstructive pulmonary disease who have acute attacks after catching a cold. As long as they are not combined with special infectious pathogens, they will not infect their children even if they cough every day.

At present, there are still some unclarified controversial points in the academic community, such as the transmission characteristics of some rare respiratory viruses and whether there are potential transmission risks of pathogens combined with acute attacks of some chronic diseases. There is no unified conclusion yet. If you encounter uncertain situations, it does not hurt to keep a mask with you to protect yourself and avoid disturbing others.