Mailbox: do COVID vaccines contain harmful DNA?

Listener Luke sent us a concern he's been hearing about the COVID-19 vaccines. Chris Smith answered:

Chris - Luke, be reassured that is absolutely not the case.

I think where this might have come from is that the vaccine that's currently being rolled out in the UK - soon to be in other countries - is Pfizer's vaccine.

It's a genetic vaccine, yes; but it doesn't use DNA though, it uses a related chemical called RNA. It's just one small piece of the genetic code of the virus. And it's used to program cells temporarily, to show the immune system what coronavirus' outer coat looks like so you make an immune response.

The piece of RNA, the short piece of genetic information that goes in, is quite quickly degraded in the body, so it doesn't hang around very long. There's no permanent rearrangement to your genetic code.

And, really, the difference here between what happens when you catch coronavirus for real and when you're programmed with this vaccine is very, very small. It's very similar to what happens when you naturally catch a virus.

So we judge it to be extremely safe, and the only long term effect is you become immune to the virus and hopefully therefore won't become ill if you encounter coronavirus for real.