How effective is the Shingles vaccine?

These days, the shingles vaccine (for herpes zoster) can be found at just about any pharmacy. However it’s been hard to find real numbers on the benefit of this vaccine and so once again scare tactics come into play to get people to get the vaccine. How effective is it really? (Please note all these studies were done on healthy seniors, whose incidence of shingles is higher than younger populations.)
new study came out which adds to a previous study showing that the vaccine reduces the burden of illness by 50% and the incidence of post-herpetic neuralgia (where the pain of shingles never goes away) by 60%. In the new study, it looks like the benefit of the vaccine drops dramatically after the fourth year, so people would need to get a new shot every 5 years or so.
So, the cumulative risk reduction is about 50% for getting shingles and 60% for getting post-herpetic neuralgia, which sounds great, but what does that really mean for the person getting the shot. After all, if you wore a metal helmet around all the time, it might reduce your risk of getting killed by a meteorite by 50%, but the risk of getting hit my a meteorite is so small in the first place (less than 1 in 5 billion/year) that it’s not worth the trouble to wear the helmet.
In the study, the annual risk of getting shingles in seniors was 1.1% without a vaccine and 0.54% with the shot, meaning 0.57% of the people who get the vaccine will avoid shingles because of it. Put another way, if 175 people got the vaccine 1 person wouldn’t get shingles because of it. Usually, shingles is a temporary annoyance (about 1 in 8 seniors getting shingles will get post-herpetic neuralgia), so 175 shots and $38,500 (around $220/shot) seems like a lot to prevent 1 case of shingles. But wait! The shot gives similar protection for about 5 years, so we have to amortize that cost over 5 years: 35 shots and $7,700 to prevent 1 case of shingles.
However, post-herpetic neuralgia can be quite devastating, so what does it cost to prevent that? The risk in seniors is about 0.14% per year and goes down to 0.046% with the shot, so 0.09% of those who get the shot will avoid post-herpetic neuralgia each year. That’s 1087 shots, but spread over 5 years it’s only 217 shots to prevent 1 case of post-herpetic neuralgia at a cost of around $48,000. Compare that to the risk if avoiding a second heart attack by taking a statin: 50 people taking it for 5 years to prevent 1 heart attack at a cost of (say $20/month on the cheap end: $1200/person x50 people) $60,000.
What does all this mean to you? If you are a senior and get a shingles shot (for about $220), you have a 1 in 35 chance it will prevent you from getting shingles over the next 5 years and a 1 in 217 chance it will prevent you from getting post-herpetic neuralgia in the next 5 years. Better odds than wearing a meteor-protecting helmet (everyone on the planet would have to wear one for a few years to prevent 1 death from meteor), but still something to think about.
Also, note that having shingles is at least as effective at preventing future episodes of shingles as the vaccine is, so no need to get the vaccine if you’ve had shingles within the past five years.
Finally, understand that this is only looking at the simplest to measure outcome of the vaccine and monetary costs associated with it. Costs from side effects haven’t been discussed. Whatever immune dysregulation may occur from this vaccine is not only difficult to measure (it isn’t going to happen right away so would be hard to connect with the event of being vaccinated), but actively hidden (any reaction severe enough do trigger a lawsuit and prompt enough to implicate a vaccine bypasses the normal court system and goes to a special vaccine court, where all outcomes are kept secret, so there is no record of how much of a problem there is from any vaccine).