Today I got shot (a third time)

Tagged: PharmaAndBiotech / Statistics

Today I got shot a third time! No, not a COVID-19 booster (though that’s getting pretty interesting, but its time is not yet). Today I got the first of 2 doses of the formerly-scarce Shingrix vaccine against shingles.

What’s shingles?

The childhood disease of chickenpox is a viral infection from a little beast called varicella zoster virus, a form of herpes virus also known as human alphaherpesvirus 3 (HHV-3). That’s bad enough that every kid should get the vaccine, which has been around since 1995.

The evil little virus then goes dormant in your body, lying in wait for decades. When you get old enough, it can flare up again. Not as chickenpox, but as a direct inflammation of nerves, severely painful, called postherpetic neuralgia (PHN). It’s so painful as to be disabling. The word neuralgia should be scary: “neuro” means involving the nerves or nervous system and “algia” means pain — it’s directly inflicting pain through stimulating nerves. For years. Sometimes it occurs in the eyes and causes blindness.

That is the nasty thing called shingles.

But am I actually at risk for it? I’m too old to have gotten the chickenpox vaccine, which came out when I was 40 years old. I don’t remember having chickenpox. However, the epidemiology says that 95% of adults in the US have had chicken pox [1], apparently based on detecting dormant virus in their bodies.

So, yeah, everybody’s at risk for it. I would like to avoid it.

Shingles vaccines

Fortunately, there are vaccines. And in these pandemic days, we all know vaccines are good, right? C’mon, don’t make me glare at you. Right?

Right.

Zostavax pack shot So some years ago, I had Zostavax, a shingles vaccine from Merck. It was all that was available then, when I turned 60. It’s got a vaccine efficacy of 50% – 60% [2], which back in those days was considered pretty good.

Recall that vaccine efficacy is given by:

\[\mbox{efficacy} = 100.0 * \left( 1 - \frac{\Pr(\mbox{infection} | \mbox{vax})}{\Pr(\mbox{infection} | \mbox{non-vax})} \right)\]

So an efficacy of 50% – 60% means that, by getting vaccinated, you have 50% – 60% less risk than the unvaccinated population. (This is about the efficacy range of a flu vaccine, and those are certainly worthwhile.) It’s not dramatic, but it’s worth it given how safe the vaccine is and how painful and sometimes disabling shingles is. At the time, the FDA recommended it to people over 60.

Shingrix pack shot But then along came, from GSK, a bright shiny new recombinant vaccine called Shingrix. In adults aged 50 – 69, such as your humble Weekend Editor, it has a stunning efficacy of 97% in preventing shingles. [3] That’s actually better than the 95% efficacy for the mRNA COVID-19 vaccines about which we gushed so enthusiastically earlier this year.

What’s more, it’s even recommended for persons who have previously received Zostavax.

So… want some of that!

The problem

It’s a 2-dose series, with the 2nd dose 2 to 6 months after the first.

Unfortunately, in recent years it’s been in short supply and people actually had trouble getting the 2nd dose in time. For the last 3 years, I’ve asked my doctor about it at each annual checkup. Since they reserve the second dose at the time they give you the first, they’re being absolutely certain the second dose will be available to you.

Unfortunately, that means they’re often out of it: all doses in their freezers are spoken for by somebody who’s already gotten the first dose.

So for 3 years, I waited, hoping each time to get Shingrix. For whatever reason, maybe people putting off health care during the pandemic, there’s plenty of it now. So I could just waltz into my local drug store, say I wanted Shingrix, fill out a few forms, pay $25 bucks, show them my Medicare Part D card, and get jabbed by a very pleasant woman in the pharmacy.

So I hope it’s still available in 2 to 6 months!

(Oh, and the Weekend Editrix lucked out: she got both doses of Shingrix earlier this year, while we were all waiting for COVID-19 vaccine availability.)

Expected side effects

The usual: sore arm, fatigue, headache, body ache, and so on. It goes away in 1-3 days, so nothing to worry about. It’s a little more severe than a reaction to a flu shot, but way, way less severe than shingles.

The Weekend Editrix took a couple days off to lie on the couch with her iPad when she got hers earlier this year. I may do that. Happily.


Notes & References

1: Boston Children’s Hospital, “Chickenpox”, Conditions and Treatments.

2: Centers for Disease Control, “What Everyone Should Know about Zostavax”, Vaccines and Preventable Diseases, 2020-Nov-19. NB: Zostavax was discontinued in the US in favor of the superior Shingrix vaccine, so this information is purely for historical archival interest only.

3: Centers for Disease Control, “What Everyone Should Know about the Shingles Vaccine (Shingrix)”, Vaccines and Preventable Diseases, retrieved 2021-Jun-29. NB: This reference claims 99% of Americans have some of the chickenpox/shingles virus in them, more than the 95% claimed in the first reference. Basically, we’re all at risk for shingles.

Written Tue 2021-Jun-29

Gestae Commentaria

Ach - good luck! Second Shingrix shot (way back in that pre-pandemic world) knocked my on my keister. But worth it, from what I’ve heard from folks who’ve gotten shingles instead.

Weekend Editor, Wed 2021-Jun-30 16:37

Thanks for the good wishes, Pablo!

So far, so good: really sore arm, pretty tired this morning, feeling like I’m a bit fragile. I’ll take that, in exchange for the reduced risk of the misery of shingles.

2nd dose sometime between the end of August and December, so that’ll probably be more “exciting” and I’ll whine about it then.