Thread by @WheatNOil

China recently approved the Sinovac vaccine and since apparently this is what I do in my spare time now, let’s talk about how that one works!

It works in yet a different way than the mRNA (Pfizer / Moderna) or the AstraZenica vaccines.

The Sinovac vaccine is a more traditional vaccine type. It’s an “inactivated” vaccine. That’s different from another traditional vaccine type: an “attenuated” vaccine.

I should take a moment to clarify the difference.

Think of an “attenuated” vaccine (also sometimes called a “live” vaccine) is when you take a virus and make it way less dangerous. It’s basically your body fighting against this guy.

Think of an inactivated vaccine, like the Sinovac one, as a dead virus. It’s your body fighting against this guy. (I assume you’ve all seen Weekend at Bernie’s. If not, you should... for science.)

So you basically get a dead virus. Your immune system sees this dead virus and much like the characters in Weekend at Bernie’s, it doesn’t think the virus is dead. It assumes this weird unknown virus is a problem and attacks it, then forms a memory of it.

(If this sounds familiar, it’s because this is the common pathway for all vaccines. At some point your immune system does the whole “what the fuck is this?”, attacks it, remembers it, and says “get the fuck out of here” when it sees that thing again.)

‘On average’, your immune system will respond more strongly to a live but weakened virus than it will a dead virus. I mean, your immune system isn’t totally dumb. But a dead virus is safer for some people with really compromised immune systems.

So, the obvious question: does it work?

My honest answer: I... don’t know. It’s been harder to find data compared to the other vaccines I’ve talked about. That doesn’t mean it’s not effective. I just can’t find clear info.

There’s been some interim reports. Really positive stuff out of Turkey, over 90% but that’s only interim. A bit less clear out of Brazil. Initially they said at least 50%, then revised it up. They’ve been using the vaccine in China for emergency use for months now.

We can get into the weeds with these little bits of data, but at the end of the day, the Phase 3 trials haven’t been fully released yet. So it’s ‘probably’ effective but we’ll know better when the data is released. (And someone let me know if it has been and I’ve missed it.)

So for now, it’s worth knowing it’s a more traditional ‘inactivated’ virus. It’s being tested in multiple centers around the world. The interim results are reported as positive. We haven’t really seen the full data yet. I’ll update as we know more.