Shocking! Coronavirus can infect a healthy person in 10 minutes!

The novel coronavirus spreads through body fluids coming out of the nose and mouth of an infected person. Acts of breathing, speaking, coughing and sneezing release loads of virus particles into the air. Besides, humans have the habit of spitting and blowing their noses.

How long should you be exposed to an infected person to get enough novel coronavirus particles to turn yourself into a Covid-19 patient? Comparative immunologist Erin Bromage of University of Massachusetts Dartmouth conducted a study to theorise a formula of coronavirus infection: "Successful Infection = Exposure to Virus x Time".

He has calculated time of exposure for a successful infection in the cases of simple breathing and normal conversation wherein one healthy person shares air space with an infected person.

In a single breath, a person releases 50-50,000 droplets and aerosols. We don't usually realize that breathing releases so much of fluid in air. Those wearing specs must have noticed vapour condensing on their eye glasses while wearing a mask that's the released fluid at work.

Under normal weather conditions, most of these droplets quickly fall to the ground under the force of gravity. Some remain suspended for some time. There is no study on how many novel coronavirus particles come out with every breath an infected person exhales but this study on influenza virus puts the number at 20-33 per minute.

Assuming 20 particles per minute as the rate of release, Bromage said an infected person would release 1,000 novel coronavirus particles - enough viral load to infect a healthy person who breathes in the same air - in 50 minutes.

Meanwhile, if the infected person is in conversation with the healthy person, the infection dynamics changes quickly. Speaking releases 10 times more droplets into air. It means a talking person would release more than 200 virus particles into air every minute. So, a Covid-19 patient would release 1,000 novel coronavirus into the air in just five minutes while speaking. If all these virus particles are inhaled by a healthy person, five minutes is enough exposure time to catch a coronavirus infection.

However, human nostrils are not designed to suck in all virus particles like a vacuum cleaner. This gives the healthy individual more time to flee from an infected air space without inhaling too many particles. But the chances are still high of inhaling a large dose of released viruses, as a recent study has found that SARS-CoV-2 droplets stay in air for up to 14 minutes.

Using his "exposure to virus x time" formula, Bromage says, "Anyone you [Covid-19 patient] spend greater than 10 minutes with in a face-to-face situation is potentially infected. Anyone who shares a space with you (say an office) for an extended period is potentially infected."

Coughing and sneezing release hundreds of millions of viruses that travel at a great speed (80-320 kmph) and have high infectability. Bromage says a healthy person just needs to go to the room where an infected person had been coughing or sneezing and take a few breaths to catch coronavirus infection. Since a large portion of Covid-19 patients have been asymptomatic, the healthy person does not know if the individual she is in conversation with or the one who is sneezing has set enough coronavirus free to infect her.