MMRV - how does it work for preschoolers?

[StillInMyPJJs]

DS (3 years) is due the MMRV vaccine, he has not had chicken pox. Im happy for him to have the MMRV vaccine, but for his age group he would get 1 dose. Whereas there are 2 doses for the younger ones now getting the vaccine.

Would it make sense to get a second dose of the Varicella vaccine privately? Will it be long lasting with only 1 dose?

Realistically, even 2 doses is likely to only last until early adulthood, same with MMR immunity generally. We know this from clinical trials with the 2 dose version. Measles, mumps and rubella are serious childhood illnesses and the goal is to get children to adulthood without serious illness or death. Adults are less likely to get them even if they are non-immune and if they do, they aren’t serious.

The problem with chickenpox is that it IS more serious if you get it as an adult. With a boy, this is less of a worry. He might get really ill with chickenpox as an adult when immunity wears off, but the real concern is that chickenpox is dangerous if you get it during pregnancy. There will eventually need to be a booster campaign for reproductive age women, I suspect, to make sure they have full immunity going into pregnancy. We aren’t there yet because those of us of reproductive age now all got chickenpox so we have full immunity anyway.

It’s a bit like the MMR anyway. It wears off and he may need a booster. I had to have the MMR again in my 30s as work in the NHS and I had no measles immunity apparently. 🤷🏻‍♀️ I would get the NHS one now as standard, but it will be an issue to raise when he’s an adult if he needs a booster, especially if he decides to have children with a partner who may not have full immunity. But for now, it will do the job.

I’m afraid I can’t agree that chicken pox is less serious for a male as I knew a fit and healthy man who caught it, developed chicken pox pneumonia and died.

my husband had mumps as an adult and was told that it would likely lead to him being sterile afterwards. (It didn’t but I guess it could have done 🤷‍♀️)

I had the same with my DD who is 3. I asked the nurse giving the vaccine and she said there would be a catch-up program for children their age, so the 2nd dose should get given in due course.

That is what I used to believe too, until I read this thread. It is full of really helpful info on how long the vaccine has been shown to last in countries who have been using it for decades. It also highlights the very beneficial reduction of the risk of shingles in later life.
https://www.mumsnet.com/talk/am_i_being_unreasonable/5491633-to-ask-for-opinions-on-varicella-vaccine-vs-natural-immunity

Re OP's original question - I believe the single dose for older children is a cost/benefit decision. They think it's likely that children of this age have already had CP, and that two doses are therefore not a sensible use of money. But they're offering one to give some immunity to children who have not yet been exposed.
My children are in the same position - they have definitely not had CP yet, but will only be eligible for a single dose. We are considering getting them the second dose privately, but it's a five hour round trip for us to the nearest place and this is definitely weighing into our decision making! If it was closer I would definitely get it.

Thanks all!