If they want to hurt him there are a million ways they can do it. Most obvious is via his food. Or they could fake suicide.
I don't believe they want to kill him. They probably want to make an example of him. Get other journalists to toe the line. Though most of the bastards are well in line already.
If he was a diabetic on insulin would he stop taking his shots in there coz he can't trust them? I reckon he'd say "hell with it, give me the shot".
Same with the vaccine.
Whether he thinks the vaccine is safe is another matter. It's a matter of playing the percentages. I just had my second shot of Pfizer five days ago. Sore arm and a bit fluey for several days. Now okay again.
Blood clots are pretty rare in any vaccine but Pfizer has even less than Astra Zeneca. So, if he decides to have a jab insist on the Pfizer. Assuming he can insist on anything in there.
Regarding reading up on the vaccine - if he can't do that all he can do is rely on the opinion of those he trusts. He and they seem like intelligent folk - I doubt they're at home listening to broadcasts from old men in padded armchairs.
Also, I reckon most of the prison officers won't be vaccinated. Likewise the inmates. So, he needs to protect himself best he can.
So, if it was me in there I'd have the Pfizer. And I'd have it in my non masturbating, sorry, non writing arm. (Mind you, I reckon three days of abstinence builds character. Guess I'll never know the truth of that).