Chicken Pox immunity

[Loach]

Ok I have read up some on the internet but I know that you people here have a way of breaking it down better than most sites.

I'm 45 years old and I have never had chicken pox. I have been exposed many many times. So I have several questions.

How common is being totally immune to chicken pox?
Is it recommended I get the vaccine? (The Army probably stuck me with it at sometime)
Can you be immune to chicken pox and then lose immunity later in life?
Is reaction to being exposed to chicken pox at all related to how you react to small pox?

I ask the last one for a reason. I was one of the last generation who got the small pox vaccine when I was a baby. I almost had no reaction to it. I have a scar that is less than a quater of an inch. I received the small pox vaccine again in 2008 when I was deploying to Iraq. Again I had a very mild reaction. A tiny scar that you would never see if you didn't know to look for it. Made me wonder if it was related at all to my lack of reaction to being exposed to chicken pox.

Feel free to answer any questions about it I forgot to ask.

[Szlater]

Chickenpox/Varicella is part of the standard US Army vaccination programme... So you probably already had it.

AFAIK, chickenpox is more closely related to herpes than smallpox. Smallpox is a member of the poxviridae family, whereas chickenpox is in the herpesviridae family of viruses.

They only share the pox name...probably from a time before viruses had been identified.

[Jackmannii]

Quite likely the OP, in addition to being vaccinated, had a subclinical case of chickenpox at some time (likely as a child) and didn't display obvious symptoms. There'd be no way now to tell for sure (antibody titer could relate to prior vaccination as well as prior infection).

You'd be a candidate for shingles vaccine after age 60.

[Eva Luna]

I was in a similar situation to you - never had the vaccine or the disease. When my sister was diagnosed with shingles a couple of years ago, I decided it was worth looking into. My doc did an antibody titer and determined I was not immune, and recommended I get the vaccine - which I did just a few months ago.

Shingles is no fun - my sister ended up in the ER.

[samclem]

Originally Posted by Jackmannii

Quite likely the OP, in addition to being vaccinated, had a subclinical case of chickenpox at some time (likely as a child) and didn't display obvious symptoms. There'd be no way now to tell for sure (antibody titer could relate to prior vaccination as well as prior infection).

You'd be a candidate for shingles vaccine after age 60.

The FDA in the US has approved the shingles vac for people over 50 as of last year. While our OP may not be a candidtate for ituntil age 60, people who had chickenpox as youngsters can now get the shot before age 60.

[Loach]

Originally Posted by Eva Luna

I was in a similar situation to you - never had the vaccine or the disease. When my sister was diagnosed with shingles a couple of years ago, I decided it was worth looking into. My doc did an antibody titer and determined I was not immune, and recommended I get the vaccine - which I did just a few months ago.

Shingles is no fun - my sister ended up in the ER.

I am going to ask about getting a titer when I go in for my next physical.

[FoundWaldo]

I'm not much younger than the OP, was always told "you must be immune" or "you must have had a mild case as a kid." Then last year I got it. And it sucked (but not as badly as some people lead me to believe it would, so there's that). If I could do it over again, I'd have gotten the vaccine just be sure...

[Chronos]

A mild case isn't even necessarily enough to confer immunity, either. Both my sister and I have had chickenpox twice, and in both cases the first one was a mild one.

[Alley Dweller]

I know doctors always want you to get the titer before they will prescribe the vaccine, but I wonder why? Wouldn't it be simpler and ultimately cheaper just to get the vaccine?

Can the vaccine hurt you if you already have chicken pox antibodies?
If not, why waste time and money on testing? Why not "if in doubt, administer vaccine"?

[racer72]

Originally Posted by samclem

The FDA in the US has approved the shingles vac for people over 50 as of last year. While our OP may not be a candidtate for ituntil age 60, people who had chickenpox as youngsters can now get the shot before age 60.

Sure wish I had known this, I just went through a case of the shingles at 55. I was told to wait a year to get the vaccine.

[kambuckta]

Originally Posted by Chronos

A mild case isn't even necessarily enough to confer immunity, either. Both my sister and I have had chickenpox twice, and in both cases the first one was a mild one.

I've had chickenpox twice two, and both episodes were doozies. First time at 15 I was very sick, second at 21 even sicker. Still got a couple of facial scars as testament.

Hopefully I'm immune now.

[DSeid]

Originally Posted by Alley Dweller

I know doctors always want you to get the titer before they will prescribe the vaccine, but I wonder why? Wouldn't it be simpler and ultimately cheaper just to get the vaccine?

Can the vaccine hurt you if you already have chicken pox antibodies?
If not, why waste time and money on testing? Why not "if in doubt, administer vaccine"?

The lack of "cheaper" was what drove the other option for adults, many of whom are already immune (by blood test result) from cases that they do not even recall.

vaccinating all has an incremental cost of $2 to $16 million per QALY gained compared with testing followed by vaccination

QALY = quality adjusted life years.

Of course this was 12 years ago when most under 30 had been exposed to chickenpox many times. It would be interesting to see more current data for those who have grown up without such presumed exposures. Possibly the vaccinate without testing strategy would come up on top now. I suspect it would.

[Szlater]

Originally Posted by DSeid

The lack of "cheaper" was what drove the other option for adults, many of whom are already immune (by blood test result) from cases that they do not even recall.QALY = quality adjusted life years.

Of course this was 12 years ago when most under 30 had been exposed to chickenpox many times. It would be interesting to see more current data for those who have grown up without such presumed exposures. Possibly the vaccinate without testing strategy would come up on top now. I suspect it would.

I'm a little confused by their range for cost/QALY.

Is that comparing testing + vaccine to vaccine alone, where there are interactions that would have been prevented if testing had been done thereby driving up the cost/QALY due to treating/accounting for the interactions?

Or are they saying that the hazard of chickenpox is so low that the vaccination poses more risk, if given routinely, than if it were targeted only at those individuals who had negative titres?

[DSeid]

Originally Posted by Szlater

I'm a little confused by their range for cost/QALY.

Is that comparing testing + vaccine to vaccine alone ...

Yes.

Cost of vaccinating everybody without a history and savings associated with doing that, compared to cost of testing everybody without a history, vaccinating those who are not immune and who do follow up (at different compliance assumptions) and the savings associated with that.

Again using the data of the time which is now out of date, so the conclusions may be different. By now the odds of being immune without a clinical history or past vaccination are likely significantly lower, at least for those under 30.

[davekhps]

Just stopped in to thank the twice-pox freaks for posting in the thread-- nice to know I have company! .

Got it bad at age 7, got it again at 20. Thankfully, the second time around was mild as heck (I just thought I had picked up a strange rash, the docs showed me otherwise... back in those pre-internet days I had no idea that you could get chicken pox twice).

A co-worker of mine just this summer got the chickenpox for the first time at age 43. She did not enjoy it.

[Digital is the new Analog]

My sister had chicken pox when I was about 10 - we lived in the same house, used the same bathroom, etc. But she spent most of the course of the disease hiding in her room.

I've never had chicken pox, as far as I know. I assumed I had developed an immunity from my sister. I discussed it with my doctor at one point, and he suggested that I just get the vaccine anyway. So I did.


-D/a