Many anticancer drugs are immunosupressants (as a side effect - kill rapidly dividing cells (many types of cancer) which unfortunately includes hair follicle cells, gut lining and... white blood cells such as leukocytes, monocytes and the other ones that zap infections). So it's harder to mount...
Got my first jab today :rave::rave::rave:
Had to drive to Deal, though. Twenty miles. Luckily I can. Nothing offered in my home town. And I booked it, with difficulty, online. I pity the poor sods who struggle with the internet, or can't drive.