# The online application calculates the risk of catching Covid-19 in various scenarios

Outdoor spaces are safer than indoor spaces to catch the coronavirus, and more people are at greater risk than small groups, public health officials often remind us in the midst of the pandemic. But a new online tool can help you determine how likely you are to catch coronavirus if someone in your home, office, or school is infected.

Researchers at the Massachusetts Institutes of Technology have turned their complex mathematical equation for determining the risk of catching the coronavirus if a person in a room is infected with Covid-19 into a practical interactive tool.

Anyone can use it to find out how long it is safe to stay in a room of virtually any size or type, with between one and 100 people if one has the virus.

For example, the tool allows people to change the size of the room; what ventilation, if any, is present; what masks are worn; how well do people wear their masks; and how loud and gregarious people are.

It allows users to simulate the risk of mingling during the holiday season in their dining room, living room or kitchen as well.

The tool reveals that it doesn’t matter what size or type of room, but the types of masks that people who occupy it wear and the ventilation system it is equipped with can significantly increase or decrease the risks.

You can try the interactive tool for yourself here.

The MIT tool’s settings for homes, schools, and restaurants suggest that a few people in any location are likely safe for days in a home with more space, or hours in a restaurant – but once rooms are more densely occupied, the risk increases.

An interactive tool allows people to calculate the risk of catching Covid19 if someone in the room tests positive. Ventilation and masks were deemed essential. If a meal cannot be eaten outside, such as during the winter months surrounding Christmas, opening a window can help reduce the risk, as ACBs wear high-quality surgical masks, not cotton blankets ( stock)

In a standard room with 8 foot high ceilings and each wall approximately 15 feet long, 10 fit young people, all diligently wearing surgical masks, could sit safely and speak normally for two hours if the windows were closed due to the cold outside.

But, for a family of ten, some of whom are elderly, in a standard dining room for Christmas dinner where no one wears a mask because they’re eating and the windows are closed because it’s cold outside – and there are some heated discussions with high voices – the tool reveals that the safe limit is reduced to just three minutes.

Its developers say the online site allows people to calculate risk with more nuance than just advice, often vague, to form “bubbles” or social distancing.

The calculations that inform the site were published by the authors John Bush and Martin Bazant on the pe-print server medRxiv.

In a standard room with 8-foot-high ceilings and each wall approximately 15 feet long, ten fit young people, all diligently wearing surgical masks, could sit safely talking normally for two hours if the windows were closed. due to the cold outside, according to the tool, based on calculations by MIT researchers (stock)

Scientists at MIT used fluid dynamics – or how infectious droplets can float around a room – to calculate the risks of these exposures over a period of time. However, the tool is currently only equipped to calculate based on one infected person in one room, not several.

### How the coronavirus infects the BRAIN

The coronavirus can reach the human brain after being inhaled through a person’s nose and getting stuck in their nasal mucus, a study has found.

This is the first known evidence that the coronavirus can infect neurons in the brain via the mucous membrane.

Throughout the pandemic, it became clear that the coronavirus, called SARS-CoV-2, not only causes respiratory distress but also neurological problems.

For example, one in three report symptoms such as loss of smell or taste, headache, fatigue, dizziness, and nausea.

German scientists performed autopsies on 33 patients who died from Covid-19 and studied mucus on the back of the nose – above the mouth where the throat joins the nasal cavity – as well as samples of brain tissue.

The genetic material of the coronavirus was present in greater amounts in the mucus of the nasal cavity, but the peak proteins of SARS-CoV-2 – which protrude from the virus and cling to human receptors to infect cells – have also been found in the brain.

Dr Frank Heppner, co-author of the Charité – Universitätsmedizin Berlin study, says: “Once inside the olfactory lining, the virus appears to use neuroanatomical connections, such as the olfactory nerve, to reach the brain.

This makes it useful for small gatherings, but in large places where there may be dozens of people, for example in a supermarket, the app becomes unusable.

However, people can visualize the impact of what their household’s Covid protocols can do. For example, in a 400 square foot living room, if five young people all wear an N95 respirator, they can dance and sing safely for 35 minutes.

But by dropping the mask under the chin just 50% of the time, that number drops to four minutes.

While room settings and mitigating aspects are important, the researchers say, the most critical impact is on human behavior. Specifically, wearing high quality face masks.

In their study, the researchers applied their work to two case studies that both received extensive scrutiny for their role in the spread of the disease: classrooms and nursing homes.

For a typical American classroom with 19 students and a teacher, the researchers found that without a mask, “ the expected time for the first transmission after an infected individual enters the classroom is 2.3 hours for natural ventilation and 18 hours with mechanical ventilation ”.

“With improved ventilation and judicious use of the mask, this period could be extended to several weeks, and thus exceed the recovery time from Covid-19”, they add.

Prolonged periods of physical activity, with several people talking at the same time or singing would reduce the time limit by an order of magnitude, the researchers warn.

However, the good news for classrooms is not duplicated for long-term care facilities, is that true, warning that their analysis “sounds the alarm bells” for long-term care facilities.

They say three elderly people each with 80 square feet of space in a room with open windows are only safe for three minutes if the 2m (6ft) social distancing rule is followed.

The maximum safe limit for occupying this space if someone is infected is only 17 minutes, depending on the model.

“This example provides a glimpse of the devastating toll of the Covid-19 pandemic on the elderly,” say the researchers.

“Additionally, it highlights the need to minimize the sharing of interior space, maintain adequate and unique ventilation, and encourage the use of face masks.