Thank you for your response. My mother had psoriasis as a young woman. No others immune diseases I am aware of. My doctor diagnosed the condition. In addition to the light therapy, he ordered laser therapy for my scalp, Scalp was reddened so am seeking less intense application. I'm using prescribed oils, lotions and ointments on body. He prescribed the pill Otezla which I could not tolerate. I am waiting to see whether insurance will cover Biologics injections. On the matter of the booster, he is noncommittal. He said he understood my hesitancy to get the booster. Nothing more.