Shingles

Nov 26, 2019

By Trevor Shewfelt, Pharmacist at the Dauphin Clinic Pharmacy

"Lotteries are a stupidity tax." If you don't hate me yet, let's try this one, "Lotteries are a tax on those who can't do math." I've said things like that many times before and I've always felt quite holier-than-thou. But I'm a hypocrite. I conveniently forgot about the number of times I've contributed to a group lottery ticket. You know, a bunch of people at work or a bunch of people at a Kinsmen meeting say, "You want in on this?" Of course I buy. And why? It's not that I don't know that I might as well just throw my twoonie into Lake Dauphin. I fear regret. The regret of, "What if everyone else got rich except me?" The good news is I'm being irrational in a rational way.

The world of shingles vaccines is not irrational. Let's review the basics. What is shingles? Shingles is a condition caused by the same virus that causes chickenpox, varicella-zoster virus (VSV). When you have chickenpox as a child, we say you have varicella. The varicella-zoster virus does not leave your body when the red itchy spots of chickenpox go away. Instead, it becomes inactive in the nerve cells called the sensory dorsal root ganglia. The virus goes dormant and just sits there for 30,40, or 50 years. In some people, the virus then reactivates and causes a rash. This time though, instead of being itchy like chickenpox, the rash is usually painful and only on one side of the body. This condition is known as shingles. The medical term for it is herpes zoster.

Doctors talk about two main things when they talk about shingles or herpes zoster. They talk about the reactivation of the virus in the nerve cell and its accompanying rash, and they talk about postherpetic neuralgia. Postherpetic neuralgia is nerve damage pain that remains after the shingles rash is gone. Postherpetic neuralgia can result in severe pain. Common sites of postherpetic neuralgia pain are the torso and the face. Sometimes the pain is so severe patients are unable to wear clothing that comes in contact with the lesions or to be outside in the wind because of the sensitivity of the skin on the torso and face. There have even been cases of loss of vision and facial scarring. The incidence of shingles and postherpetic neuralgia will probably increase as the population ages. The rate of shingles and PHN rises sharply after the age of 50. The number of people with shingles who get postherpetic neuralgia rises from 10% among the general population to as high as 40% among those over 50. This is why guidelines say people should get a shingles shot starting at age 50.

Recently a second brand of shingles vaccine has hit the market. There used to just be Zostavax. The new kid on the block is called Shingrix, and it is probably better than its predecessor.

The older vaccine, Zostavax, is a live attenuated vaccine. That means it has actual virus in it that has been weaken. But if you give it to someone with a very weak immune system, like someone on cancer chemotherapy, they could theoretically get the disease. Shingrix is a non-live recombinant vaccine. It is made of broken up virus parts. It can't give the disease to an immunocompromised patient. Shingrix also has an immune booster ingredient that causes the immune system to react very strongly to the vaccine. That leads to why everyone is excited by Shingrix. Shingrix claims that it prevents shingles 90% of the time, while Zostavax only prevents shingles 51% of the time. Put another way, about 37 people need to get a Shingrix immunization to prevent 1 case of shingles over 3 years. It would take 59 patients immunized with Zostavax to prevent one case of shingles.

Of course, Shingrix has some downsides. Zostavax is expensive and not covered for most people. Shingrix is even more expensive. Zostavax is just one shot. Shingrix is two shots separated by 2 to 6 months. Shingrix hurts more. This is probably because of the special immune boosting ingredient. You are much more likely to have pain, rash and flu like symptoms with Shingrix than you are with Zostavax.

It is okay to get Shingrix at the same time as the regular flu shot without an immune boosting adjuvant. It is probably fine at the same time as pneumococcal and Tdap vaccines, but studies are still ongoing.

In Zostavax, shingles immunity falls off quickly in year 1 and is just about gone by year 5. We think Shingrix might give immunity out to 7-9 years, but the studies aren't complete. Shingrix should be fine in immunocompromised patients, but studies are still on going.

Should you get the Shingrix shot if you previously got the Zostavax shot? Guidelines now say yes. You can give Shingrix to someone who previously got Zostavax, but wait at least 8 weeks between Zostavax and Shingrix. It is recommended that a patient wait a year after previous shingles episode before getting a shingles vaccine. This is because the body should be relatively immune to shingles for the first year after an episode.

I love books and podcasts about behavioral economics like Freakonomics and Choiceology. Wait, wait - don't tune out just because I said economics. Behavioral economics looks at rationally irrational stuff we do every day. It looks at how regret, or loss aversion is a very powerful force in why we do stuff. And behavioral economists have even come up with ways to make our irrationality work for us. Prize-linked savings accounts are playing the lottery for good. If a bunch of people save in these special accounts, most of the interest from their savings goes back to them. But a small part of the interest stays in a pool. Once a year, this pool of money is randomly given to one of the savings account holders. It is a lottery where you have to save to play and even when you lose you have been tricked into saving some money. Now that's neither taxing nor stupid.

The information in this article is intended as a helpful guide only. It is not intended to be used as a substitute for professional advice. If you have any questions about your medications and what is right for you see your doctor, pharmacist or other health care professional

As always if you have any questions or concerns about these or other products, ask your pharmacist.

  1. and prevention of herpes zoster: A Canadian perspective-https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2852282/

Freakonomics - http://freakonomics.com

Choicology - https://www.schwab.com/resource-center/insights/podcast

David Asch TedTalk - https://www.ted.com/talks/david_asch_why_it_s_so_hard_to_make_healthy_decisions

 


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