Is Covid in the air? Can someone explain it simply? How does it spread?

[allthingsbrighter]

Sorry if this is a really bizarre question.

How exactly is Covid spread? How do you catch it?

Is it close contact with someone? Or can your get it just from it being in the air?

So for instance. My hair dresser works from home.
So say if she’s negative, but she has a client who is positive (say 48 hours before the onset of symptoms) and that person is in her house before I go, does the virus stay in the air so I’m at risk of getting it, even if I don’t have contact with the infected person?

Or what about if I’m in an office and we’re all distanced by 2m. If someone has it does it stay if the air and I can catch it by walking into the same air space?

Probably over simplifying, but here goes.

It lives in your body and when you shed fluids it can be picked up by someone else.

So when you talk / breathe / cough you spray spit. You touch your nose and pick up snot. You rub your eyes and get moisture from there. You go to the loo and pee or poo and when you flush with the lid up it spreads water from the loo into the air.

So you can breathe in moisture that someone else has breathed out or expelled through talking or coughing or sneezing. That's what masks are for, to stop an infected person spreading that moisture into the air around them.

Or that moisture can settle on surfaces or be transferred there by someone coughing into their hand and touching a surface. Then the next person comes along, touches the same door handle or whatever, then touches their mouth/nose/eyes and becomes infected.

This is why they're saying you should have windows open if you're indoors with others, even at 2m distance, because it at least exchanges some air and any virus floating around has a chance of being blown out the window.

There is evidence for COVID spread via fomites (touching surfaces where virus has settled and then it getting in via touching mouth/nose/eyes), as well as droplet spread (hence masks and 2m distancing). Until a few months ago, aerosol spread which is what I think you are mainly thinking of where it’s just “in the air” hanging around waiting to infect someone, was thought less likely. But some recent studies suggest that a degree of this is probably present too. However good ventilation (having windows open or being outside), wearing masks, limiting the time you are in the room with someone and keeping 2m distance all help to reduce the risk of inhaling enough virus particles to be infected. In the situation you describe it’s technically possible to get an infection from your hairdressers previous customer if they happened to be positive, but less likely if she leaves a bit of time between appointments, everyone wears a mask, the windows are open, the room is clean etc. I’d try to avoid going to the loo in her house!

It doesn't just hang there and will disperse in the air especially if there is good ventilation. If they both wear masks then this stops as many virus particles from getting into the air in the first place.

Any particles that fall on surfaces can be wiped away and hands should also be washed to get rid of any particles you touch on those surfaces.

@rachelbloomfan

I’d try to avoid going to the loo in her house!

What difference would that make?

@dementedpixie

It doesn't just hang there and will disperse in the air especially if there is good ventilation.

So if you’re 2m apart, someone who is positive talks, coughs etc (with a mask on)
can you catch it by being in the same room?

The best way is to consider it like glitter. Once open it gets everywhere! But one or two pieces of glitter you find on your trousers is less catastrophic then a whole heap on the floor...it’s airborne and a higher viral load is the issue.

There's a university study about this at the moment. I'll see if I can find it.
I'm assuming you can get it in the same room with masks on. I won't get my hair cut for example.
Every room in my house is ventilated now as I have dc's at secondary school.

I think what confuses me is how people are catching it.

My friend caught it and the only place she had been was the supermarket.
She didn’t have close contact with anyone there. So even with a mask and keeping her distance, she caught it.

It hangs in the air for a bit, but not hours/days.

If you’re in a poorly ventilated office, restaurant or classroom for an hour and someone in the room is infected and breathing out droplets, they will spread around the room - for example, at an indoor choir practice one infected person passed it on to almost everyone else in the room, even though they were sitting 2m apart.

If your hairdresser has an infected person in, has all the windows open, they wear a mask, and the room is aired out before you arrive, any drops in the air will dissipate making the chances of you being infected very small.

You need to think ventilation, masks, proximity and length of time you are in the space.

@megletthesecond

I won't get my hair cut for example.

Why? Because of the close proximity?

@allthingsbrighter

I think what confuses me is how people are catching it.

My friend caught it and the only place she had been was the supermarket.
She didn’t have close contact with anyone there. So even with a mask and keeping her distance, she caught it.

Did she not have any contact with any other person who went anywhere though? No children or partner that goes to work/school?

She could have just been very unlucky and walked through a space that an infected person just breathed/coughed in.

@mooncakes

for example, at an indoor choir practice one infected person passed it on to almost everyone else in the room, even though they were sitting 2m apart.

Wasn’t singing proven to be a high risk of transmission though?

So if they all were in a room with masks, no singing, the risk would be lower?

@mooncakes

Did she not have any contact with any other person who went anywhere though?
No children or partner that goes to work/school?

She said she didn’t, she’d been working from home and so had her partner. They don’t have children and they only place she’d been was the supermarket.

[quote allthingsbrighter]@mooncakes

for example, at an indoor choir practice one infected person passed it on to almost everyone else in the room, even though they were sitting 2m apart.

Wasn’t singing proven to be a high risk of transmission though?

So if they all were in a room with masks, no singing, the risk would be lower?[/quote]
Yes - so enclosed room, singing/shouting, no masks, over an hour = more risk

Well ventilated room, no raised voices, masks, short period of time = low risk

Outside and over 2m apart = very little risk at all

Yes. Covid is absolutely airborne and you can catch it from the air without ever having seen the person you caught it from. How likely you are to catch it from someone in this way depends on how big the room is, how much ventilation there is, how long they were in the room and how much virus they're producing. So you're very unlikely to catch it from someone who was in the Albert Hall before you even if there's no ventilation and they were there for hours and hours but would be fairly likely to catch it from someone who spent a significant amount of time in an unventilated box room before you.

@allthingsbrighter

I think what confuses me is how people are catching it.

My friend caught it and the only place she had been was the supermarket.
She didn’t have close contact with anyone there. So even with a mask and keeping her distance, she caught it.

So supermarket it could be on surfaces of the products/card machine or just the airspace. It's why the advice is to wipe down all surfaces and this includes your shopping.

Also unless a medical grade mask worn correctly with hand washing etc then the mask doesn't prevent you from catching it just reduces the size of droplet released to the surrounding air if you are positive.

Basically there are several ways close proximity to others, surfaces, in the air large particles and in the air small particles in a poorly ventilated area.

Best way to think is that your hands are covered in glitter or paint anything you then touch is covered that's why you should wash/sanitise hands between touching things before you touch your face etc

@Scottishskifun

It's why the advice is to wipe down all surfaces and this includes your shopping.

I’ve never wiped down my shopping, never seen any advice to either.

Not saying you can’t go to the loo there if you really need to! But just saying this is likely where the most risk in the scenario you described might be, like WeeDangerousSpike said, if the previous customer flushed with the lid up and you now breathe some of that in/touch the flush button and don’t get it all off when you wash your hands etc. Just wash your hands well if you do.

Technically yes it is possible to catch it from a positive person 2m away and both of you with masks on as the masks are not impenetrable to the virus they just reduce the amount of virus that gets through, the 2m reduces the chance of droplet spread but there could be some just in the air/aerosol spread if they’ve been in the room for a while just breathing. However it is unlikely if you take all the precautions advised- mask/visor, good ventilation, social distancing, handwashing, clean surfaces.

The glitter thing is a good analogy. You need a certain amount of glitter to get into your nose/mouth/eyes to get ill and just one bit of glitter won’t do it. All the measures we are taking make it less and less likely that glitter will get to you and if you and your hairdresser and the previous customer take all of them it is highly unlikely the glitter will get through them all. But not impossible if you were unlucky eg the person before you in the hairdresser has a larger amount of glitter than the average person with glitter/your mask lets more glitter in than most masks/the windows were closed because it’s cold/you rubbed your eyes at just the wrong moment when glitter had settled just beside your eye etc.

Sometimes I think it’s best not to think too much about the possibilities as you could end up with OCD about it, but just take all the precautions advises, limit contact as much as reasonably possible etc. There is some potential risk of getting COVID with every single human contact you make. You have to weigh up the risk versus the benefit. But I’d say it’s low risk in the scenario you describe.

all yes, it's too close for too long. I'm happy to whizz around the supermarket but not sit next to someone.

Your friend could definitely have caught it from the supermarket. Also from surfaces of boxes delivered to the house etc. I think I saw some data at one point saying one of the main areas of spread was in supermarkets, which makes sense as so many people pass through there. Supermarkets are not immune to COVID!

This is an interesting a article about how it spreads in air

english.elpais.com/society/2020-10-28/a-room-a-bar-and-a-class-how-the-coronavirus-is-spread-through-the-air.html?fbclid=IwAR3xuE-I5lQiynvFGW3kCXsa46QH0WHZVHUYY6oOa4iw_8f1HHQ6Z6bTvoI

Just to note that visors alone don’t do anything to prevent spreading covid - they just stop anything from splashing in your eyes.
You still need to wear a mask over mouth and nose with a visor.

Also unless a medical grade mask worn correctly with hand washing etc then the mask doesn't prevent you from catching it just reduces the size of droplet released to the surrounding air if you are positive

Which is why I was so stressed shopping today behind 2 people who had pulled up their single layer neck warmers to use as masks . How don’t people know at this stage that that won’t prevent droplets?

Yes the droplets can be suspended in the air from people breathing out, how long for, I've seen so many suggestions in papers, from 9 mins to many hours.

Air exchange, high temperature coupled with high humidity seem safest.

This article has some images depicting the inactivation of the virus being quicker at higher temp and humidity
www.telegraph.co.uk/global-health/science-and-disease/experts-reveal-optimise-heat-humidity-reduce-covid-transmission/

Small toilets with no air exchange and people having flushed with seat up are certaintly a higher infection risk area so presumably that's why some avoid them if possible.

Although it would be possible to catch from the supermarket, I would bet that they went somewhere else. Dentist, doctor, car in garage, taxi, bus. Popped into a friend’s house, a walk with a friend