If you are based in the UK there are a few options which may suit you. Most of the UK population are now eligible for a free NHS COVID-19 vaccination.
Alternatively you can visit your local vaccination centre towards the end of their working hrs and ask for vaccination. You may not get it the first day you try this, but many vaccine centres offer this rather than letting vaccines go to waste.
If you are a Sex Worker another option is to email: contact@swarmcollective.org or admin@nationaluglymugs.org for advice on specific and discreet access.