The data are in and remdesivir seems to have some effect in treating #COVID19, but it’s not the magic bullet we were hoping for. Tons of attention is now turning to antibody therapeutics. Wondering what these are, how they work, and how promising they might be? A thread.
Let’s start by talking about what antibodies are. Antibodies are protein molecules that your body makes to fight off infection. They’re shaped like a ‘Y’ and the parts of the protein molecule at the tips of the Y are different in every antibody. 
Your body makes tons of different shapes until it finds one that fits with the surface of the virus or bacterial cell you are trying to fight. Your body uses that to get rid of the infection, and then remembers how to make it in case you encounter the same infection later.
This is why people who have had COVID-19 are unlikely to get it again. It also means that it might be possible to take the antibodies from someone who has been infected and then recovered and use these to treat someone else.
When you’re fighting an infection, receiving a drug is like getting a better weapon – it helps slow down the virus so you can win. Receiving antibodies is different because it calls upon your own immune system – kind of like getting a whole team of superheroes to fight with you.
So, where do we get the antibodies to use to treat people who are infected? There are two sources – we can get them from people who have had COVID-19 and recovered, or we can engineer them in a lab.
The first approach is called “convalescent plasma” and has been shown to have some effectiveness. The benefit is that you get a whole set of different types of antibodies – like the Avengers team. But, the drawback is that supply is limited – it’s plasma from real people.
So, what about the engineered antibodies? These can be produced in a lab and so getting a good supply is less challenging. But, the challenge is that typically only one type of antibody is made, called IgG – it's kind of like calling the Avengers team and only getting Iron Man.
However, that might still be enough to help your body win against the infection. If this type of therapy seems so effective, what are the drawbacks? As I mentioned, supply is one – plasma is very rare, and even engineered antibodies can be expensive to make.
The other challenge is that we still don’t totally understand the symptoms and progression of COVID-19. It seems that the virus sets off many other reactions in the body, such as inflammation. It’s not clear whether antibodies against the virus would stop this.
Where does this leave us? Nobody knows for sure. Given what we’ve seen for the use of antibodies against other infections, there’s reason to have hope. However, that should be tempered with the reality that there’s much we still need to learn about COVID-19 and how to defeat it.
