I'm undergoing chemo at the moment and asked my oncologist how long it will take for my immunity to recover once I have completed the course (which, thankfully, will be in a couple of weeks time). I got my booster in October last year, but she said that regardless of this, my immunity will be compromised significantly due to the chemo so I will need a 4th jab 2-3 weeks after my last chemo. I will be glad to get it as I want to start living again and be able to meet up with family and friends occasionally to get a cuppa in a (well ventilated) bar or cafe.