General, Research, Technology

How many people can infect one patient with coronavirus

The coronavirus is known to spread mainly through the air, especially indoors. Although this virus is not as contagious as, for example, measles, scientists already recognize the fact that COVID-19 able to infect most people who arein one room. This is aggravated by the lack of good ventilation and the duration of contact: tiny infectious particles that the patient exhales can hang in the air for hours in a closed room and penetrate into the bodies of other people. We offer to visually see how the infection occurs, and whether wearing masks can affect the spread of the virus.

Spoiler - very good


  • 1 How the coronavirus spreads
  • 2 How can you get infected with the coronavirus?
  • 3 Could the scream accelerate the spread of the coronavirus?
  • 4 Is it possible to get coronavirus in a cafe?
  • 5 Spread of coronavirus in school

How the coronavirus spreads

Let's take the most common situation: a person comes to visit friends or family, not knowing (we hope) that he is infected with the coronavirus.

All without masks, including the infected

After four hours of communication with this person, no matter at what distance they are from him, all the remaining 5 people are already will be infected... If we talk about a room of 20 square meters without good ventilation.

After a few hours everyone is infected

If masks are used by all people inthe room will be infected not 5 people, but 4 people. Why is that? The fact is that masks themselves do not prevent infection if contact is very long. In our case, people in the room talk for 4 hours - most masks cease to be effective after 2 hours.

Masks help reduce the risk of spread, but they are only effective for 2 hours

And this is how the picture of infection will look like if everyone in the room uses masks, reduce contact from 4 to 2 o'clock and provide air flow into the room and its exit.

In this case, only the one who is closest to the patient is at risk.

How can you get infected with coronavirus?

Currently, health authorities recognize three main ways of contracting COVID-19.

  • Salivathat is secreted by an infected person when talking or coughing and gets into another person's eyes, mouth, or nose.
  • Contaminated surfaces, although the US Centers for Disease Control and Prevention (CDC) notes that this is the least likely case. But it can be.
  • Breath - a healthy person breathes in invisible infectious particles that the patient breathes out. Without ventilation in the room, they remain suspended and eventually condense in the room.
  • Scientists from Japan recently found that coronavirus survives on the skin for up to 9 hours. Who would have thought!

    In the latter case, a distance of 1.5 meters or more is considered safe, but if you are with the patient in the same room for a long time, then she won't help.

    Virus particles can remain in the air for several hours

    Only 60 minutes an infected person can "populate" a room with virus particles, and if there is no ventilation in the room, they remain in the air and eventually infect other people.

    In the absence of ventilation, the picture is

    Could screaming accelerate the spread of coronavirus?

    According to scientists, the nature of the conversation really affects how quickly the virus particles spread in the room.

    So, if the patient is silent, then even afterhours of contact with him, the other person can be safe (if, of course, wears a mask). In a normal conversation, the threat of infection will come within 15 minutes, and with a cry - completely in 2 minutes.

    Recent scientific publications have forced the Worldthe health organization recognizes the risk of such contamination. They note that under certain conditions, people with COVID-19 can infect others, even if they are more than two meters away. This happens in closed rooms with insufficient ventilation.

    Can you get coronavirus in a cafe?

    Outbreaks of coronavirus at events inpublic places and establishments such as bars and restaurants form an important part of the spread of the infection. First of all, they are the most destructive: each outbreak of the virus in a small nightclub ends up infecting an average of 27 people.

    In one of the American nightclubs in just one night with coronavirus 173 people became infected.

    Suppose an infected person arrives at a nightclub at 19:00. He's without a mask, like everyone else.

    The patient came to the club without a mask

    By 11 p.m., everyone else will be infected with the coronavirus, with the exception of those who were relaxing on the open veranda.

    After 4 hours all are infected

    If everyone, including the infected, would wearmasks, the risk of infection would be significantly reduced. But due to the long stay in the same room and the lack of ventilation, many would still go home with the coronavirus.

    The picture is much better with a mask

    And this is how the picture of the spread of the virus will look like if everyone will wear masks, the room will be good ventilation and duration of communication will halve... Only one potentially infected person is the one who communicated most closely with the patient.

    Ventilation, masks and short contact - and almost no one gets sick

    Spread of coronavirus at school

    The same goes for any other public place, including schools and universities. A sick teacher without a mask will infect most of the children in the class in just 2 hours.

    Even with a distance, most students will be infected

    A sick teacher with a mask will infect fewer students if they are also wearing a mask.

    The mask will help correct the situation, but without the flow of air and the reduction of lessons, many will still get infected

    The risk of infection will be minimized if the lesson is cut in half and the classroom is well ventilated.

    A maximum of 1-2 people per class will become infected.

    To calculate the likelihood of human infectionused a simulator developed by a group of scientists led by Professor Jose Luis Jimenez (University of Colorado) to show the importance of factors that influence the spread of coronavirus. The calculation is not exhaustive and cannot include countless variables that contribute to infection, but it shows the development of risks based on factors that are entirely in our control. So keep wearing the mask, but do not forget that the duration of contact with people should be minimized even in this case. Better yet, try not to meet with anyone once again - you can also talk about science in our Telegram chat.