killed off the actual virus, they continue  to feel like … crap. That's super unsettling,  

but it's definitely not unprecedented. Welcome to MinuteEarth.  

Like COVID, other respiratory diseases have  “long” versions too. Babies who get RSV are  

way more likely to eventually get asthma. Lots  of people who had SARS more than a decade ago  

still have scars on their lungs. And as many as  a quarter of people who get the flu still have  

coughing fits and trouble breathing months  later. Lots of supposedly short-term viruses  

can become long-term problems, and it seems  like there are three different reasons why: 

The first is that when you get one of these  viruses, your body often sends out a bunch  

of proteins to your lungs; the proteins' job  is to irritate the area and draw in fluids,  

generally making life difficult for the virus. But  once the virus clears, the proteins are hard to  

get rid of. They sometimes end up sticking  around - and wreaking havoc - for weeks. 

The second reason for “long” diseases is your  immune system. Normally, it pumps out lots of  

different pathogen-fighting cells. But when  you're infected, your immune system switches  

to focusing on specialized virus-fighting  cells. After the infection is gone, though,  

it takes a while for the system to switch back to  a more general approach. During that time, even  

bacteria that your body could normally control  can run amok and cause all sorts of problems. 

And third, the specific tissue ravaged by  these respiratory viruses - the lining of  

the lungs - sometimes scars as it heals from  the infection, which can make your lungs less  

efficient at bringing in oxygen, permanently.  Needless to say, this is a pretty scary result. 

But these examples are from other diseases; what  do they mean for long COVID sufferers? Well, we're  

seeing all three of these processes at work - with  some differences. COVID seems slightly less likely  

to lead to bad bacterial infections than other  viruses, which is great, but way more likely to  

leave behind trouble-making proteins in the lungs,  which has sent lots of people back to the hospital  

after they think they've recovered. And because  COVID attacks lots of different cells, the virus  

can lead to long-lasting scarring not just in  the lungs, but also in the heart and the brain. 

But our previous experience with long  diseases means that we have some tools  

to fight all three of these long-term problems.  For example, doctors now know to look for - and  

treat - potential post-COVID bacterial  infections. They have also developed a  

drug to remove those pesky lung-inflammation  causing proteins AND another that causes  

cells - the ones in your lung lining, at least  - to regrow while limiting harmful scarring. 

Since the first people to get “long” COVID only  got COVID a couple years ago, we're still not  

exactly sure about its really long-term effects  - or why so many long haulers also have symptoms  

like fatigue and joint pain. But, hopefully,  the head start we got from studying other “long”  

diseases means that one day, the suffering  caused by “long” COVID will be long gone.

This video was made in partnership  with Bill Gates. Thanks Bill!