The common cold , or cold, or a cold of the most common types of infections, especially among children under the age of five, occurs colds as a result of exposure to certain viruses, and numbering more than two hundred species,   and infect these infections members of the respiratory upper Kalonf and throat, often recovering the injured during a short period, as are most simple cases is not severe,   due to the large number of cold viruses, it is not possible for the human body to build immunity against all of these viruses , It should be noted that the elderly over the age of 60 years of age are rarely infected with a cold, as it is estimated that they are infected with less than once a year, while adults are infected two to four times per year, and children, the number of times they are infected with viral infection is estimated (3-8) times per year. And the most common cases of colds are observed among children who attend nurseries and schools, and based on what has been mentioned, the incidence of colds varies with age. 
The spread of cold disease
The virus that causes the common cold reaches the body through the nose, mouth, or eyes,  and in order for the virus to multiply in the body, it must be linked to the nasal cells, specifically in the lining of the nose, and some may ask about how the virus that entered through the eyes got to the nose, The answer is simply that when rubbing the eyes, the virus quickly moves through the tear duct to reach the mucous membranes lining the nose,  and although the incidence of colds rises in the winter and fall seasons, cold weather is not considered a cause of infection in itself. Some viruses cause more common cold in these seasons than others. 
A cold can be spread through droplets from the person while he is sneezing, coughing , or talking. Upon the arrival of the spray which carries parts of the virus to another person adjacent to him, can be transmitted cold infection, especially if the spray arrived in the nose or eyes , or the other person 's mouth, and to understand the ways of spreading better can be divided into how to spread according to the contact with the injured as follows: [ 6]
- Direct contact: such as shaking hands. Where the cold virus is transmitted from the hand of the infected person to the hand of the other person, and because the cold viruses are able to live on the patient's skin for at least two hours, touching the person in contact with his eyes, mouth, or nose with a contaminated hand transmits a cold infection, and it should be noted that kissing itself does not The virus is transmitted, because cold viruses do not spread through saliva, but if it is accompanied by direct contact, cold infection may occur.  
- Indirect contact: by touching surfaces or tools contaminated with the virus, as the virus can survive on them for several hours, and therefore touching these surfaces and then touching the eyes, nose, or mouth is enough to transmit the infection. 
Risk factors for developing a cold
Despite the possibility of cold infection reaching anyone by the aforementioned spread methods, the possibility of catching a cold increases if one or more of the following factors are present:  
- Age: Children are the most vulnerable group to catching a cold, especially those who go to kindergarten (nurseries).
- Contact: the more people nearby, the more likely it is to transmit the virus. Therefore, we notice that the chance of catching a cold increases in gathering places such as airports and schools.
- The season of the year: Although the possibility of catching a cold at any time of the year, the chance increases in the fall and winter seasons.
- Smoking: Smokers suffer from colds more than others. In addition, smokers have more colds than their non-smokers peers.
- Stress: People who feel stressed are more likely to have a cold .
- Immune dysfunction: Whether the weak immune system is caused by some chronic diseases or any other factors.
Reducing the spread of colds
Self-prevention of colds
- Wash hands with soap and water well, and a sanitizer containing alcohol with a concentration of not less than 60% can be used in the absence of soap and water.
- Try to sterilize frequently used surfaces and tools.
- Maintaining body fitness and general health.
- Avoid sharing towels, food and drink utensils with cold sufferers.
- Avoid touching the nose or eyes if you suspect exposure to the cold virus in one way or another.
Reducing the transmission of colds to others
In the event that a person has a cold, its spread or transmission to others can be reduced by following the following steps: 
- The victim remains at home, and this includes not going to nurseries or schools.
- Use the tissue when coughing or sneezing, then dispose of it directly, and if the tissue is not available, it is necessary to cough or sneeze in the area of the elbow bend. So that the mouth and nose can be covered well.
- Washing hands after squeezing mucus from the nose, coughing or sneezing.
- Avoid close contact with others, such as kissing, shaking hands, and trying to stay away from them when coughing or sneezing.
- Disinfect frequently used surfaces and tools.
Common questions about the spread of colds
Can a person with a cold appear without symptoms?
Yes, it can. It is possible to be exposed to the virus but without causing disease, and this condition is known as subclinical infection, meaning that it is an infection that did not cause any symptoms or signs to appear on the infected person. As for cases that are accompanied by symptoms, they are usually mild. 
Is there a vaccine that protects against colds?
How long is the incubation period for the cold virus?
The incubation period means the period between exposure to the virus and the appearance of symptoms on the infected person, and for a cold, it ranges between two to three days, meaning that symptoms of a cold may appear on the patient after (24-72) hours of exposure. For the virus, and it may appear sometimes after (10-12) hours.  
How long do cold symptoms last?
Despite the persistence of cold symptoms for a period ranging between (3-7) days, the symptom of a cough may suffer from it for up to four weeks after infection, because the respiratory passages are more sensitive, and symptoms may continue for some patients for two weeks. 
How long can a person with a cold be contagious?
A person with a cold is able to transmit the infection to others even before symptoms appear on him,  and the person remains able to transmit the infection up to two weeks after infection, but the greatest chance of transmitting the infection to others is on the second day of infection. 
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