Thursday 11th March 1993 Morning surgery 09:50

“How do vaccines work, Dr Dennis?”
It took me a few seconds to realise that Jack was talking to me.
“Jack wants to be a doctor like you, Dennis.” Mrs Butterworth said by way of explanation.
I smiled awkwardly and wondered whether I should tell them that I wasn’t a doctor or even a medical student.
Dr Lewis looked up from the clinic letter she was reading about Mrs Butterworth.  “Come on, Dennis,” she said mischievously, “how do vaccines work?”
I took a deep breath. “When a harmful virus gets into the system,” I said, “our white blood cells have to try to get rid of it. To do this, they make antibodies. However, they have to produce exactly the right antibody for that particular virus. If a new virus attacks us, it takes our white blood cells between one and two weeks to make enough of the correct antibodies.”
“Is that why your Dad always says I will be better in a week or two when I’ve got a virus, Dennis?”
“I suppose it is,” I said. “If the same virus attacks us again, our white blood cells remember which antibody we need. They can produce them straight away, before we become ill.”
“Is that why you only ever get chicken pox once?”
“Yes, the majority of people get it once but you can lose your immunity as you get older. Most vaccines are made from viruses that have been inactivated or killed. That way, when they are injected, they trigger our immune system but do not make us ill. When the real virus comes along, our white blood cells are ready with the antibodies.”
“Thanks, Dr Dennis.”
Dr Lewis smiled. “Do you want to explain to Jack how antibodies work?”
“I know that, Dr Lewis. They punch holes in the viruses. Our teacher told us.”

“What’s the best thing about vaccines, Jack?” Mrs Butterworth asked proudly.
“I don’t know.”
“Yes, you do. You told me last week.”
“No, I didn’t!” Jack went bright red.
“You said that, when you have a vaccine, you are not just protecting yourself. You are helping to protect your family and friends as well.”
“That was what Mr Harrison told us. I don’t care if Katie gets a virus off me.”

How do vaccines work?