The riskiest activities linked to COVID-19 infection, from sharing a car to having a 30-minute conversation

• A study out this week in a leading medical journal suggests that having long, drawn-out conversations with people who are sick with COVID-19 is one of the easiest ways to get sick from them.
• The study comes out of Singapore, where researchers tracked down every single person who lived, worked, or socialized with a sick person.
• Other high-risk activities they found included: sharing a bedroom, sharing a vehicle, and being a spouse of a COVID-19 patient.
• See below for the full lists of risky acts for roommates, colleagues, and friends of COVID-19 patients.

Spending more than 30 minutes chatting with someone who has COVID-19 — the disease caused by the coronavirus — appears to be one of the most dangerous things you can do right now.

So is sharing a bedroom or a car with someone who has the virus.

Those two findings come from Singapore, where the country's impressively strict virus-tracing techniques dealt researchers a near-perfect living coronavirus laboratory this spring.

Their study, published in the leading medical journal The Lancet Infectious Diseases earlier this week, traced back every person who was a close contact of an infected patient in that city-state from January 23 to April 3: all 7,770 people who lived, worked, and socialized with people who got the virus in Singapore.

By conducting detailed surveys with those people, asking them where they went and what they did with the COVID-19 positive cases, the researchers were able to identify certain activities that overwhelmingly overlap with coronavirus infections.

Living with someone who is sick is, overall, far more dangerous than sharing any social or work activities, their study suggests. (Research by the US Centers for Disease Control and Prevention, too, recently found that living with someone who has COVID-19 is a very easy way to get sick.)

But, even so, not all household activities are created equal. Take a look at what the researchers found were some of the most risky things to do with sick people at home, ranked from high risk to low:

Going to work or socializing with a sick person are both, overall, not as risky as being home with someone who has COVID-19.

But those activities aren't risk free.

The researchers discovered that long, drawn out conversations are also a major risk factor for catching the virus in those settings. (The authors didn't specify whether conversations in the study took place indoors, or outside, where the virus would have more room to dissipate.)

Talking loudly is dangerous because it can project more virus-loaded spit into the air than sitting quietly would.

When we communicate verbally, we release both large, heavy droplets and tiny aerosols that are smaller and can stay aloft longer in the air. The more forceful the spray, the likelier it is to waft over to someone else, entering their eyes, nose, or mouth.

Keeping a distance from the people you're chatting with, and avoiding yelling and spitting when you converse is key.

That can be hard to do, though, when you're sharing a vehicle with someone, which might be part of the reason why the researchers also found that ride-sharing is another of the riskiest pandemic activities for co-workers and friends. It's difficult to avoid whatever your fellow passengers might be spewing into the air when you're in such a close, confined space.

Indeed, six National Health Service workers in the UK who recently flouted car-sharing rules there all got sick, after they took off their masks while carpooling together, the Guardian reported.

Opening a window when you're in the car and putting on masks can both help, but as this study showed, not even wearing a mask at all times you're around sick people is perfect at preventing infections.