Medicine For People!

December 2006

The Shingles Vaccine: Is It Right For You?

This year people are being offered the opportunity to be vaccinated against shingles, also known as herpes zoster. In this newsletter I examine the medical and financial implications, so you can decide whether this vaccine is right for you.

What is Shingles?

Shingles is a disease caused by the same virus that causes chicken pox. It triggers a painful rash of small blisters.

Mistakenly believing shingles was related to Herpes simplex, doctors originally named it "Herpes zoster." Most doctors still use that name, instead of the newer term "varicella-zoster," which includes the name of the chicken pox virus, varicella.

"Shingles" derives from cingulum, the Latin word for girdle, and refers to the distribution of the rash when it occurs on the trunk. Shingles can also occur on the face. We identify shingles from the characteristic appearance and distribution of the rash.

Shingles, Figure 1

Figure 1: Usual distribution of shingles rash

Shingles, Photo 1

Figure 2: Characteristic blisters of shingles rash

What Causes Shingles?

The virus that causes chicken pox doesn't go away when the pox clear but retires to the area where our sensory nerves enter the spinal cord and brainstem. If the immune system becomes less vigilant due to age, illness, or immune-suppressant drugs, the virus spreads through the nerve to the skin and causes shingles.

Shingles most often occurs in older folks. Although the disease can affect younger people, it does so less often and with less severity. Let's talk about the usual course of the illness in those over the age of 50. Initially, there is no rash, only hypersensitivity and later, pain. People may find that even the pressure of a shirt produces discomfort. Three or four days later, a few pimple-like lesions appear on the skin, then spread, blister, and become weepy. The person may be fatigued or feverish. In most cases, all returns to normal in a few weeks or months. Untreated, the skin lesions clear in about a month. In some unlucky people, the pain persists for many months.

Why worry about shingles?

Although unusual, the disease can cause three different kinds of long-term problems.

  1. It can leave scars, although this is rare in otherwise healthy people.
  2. When the nerves in the region of the eye are involved, the cornea can be damaged. Ophthalmologists can usually prevent this complication.
  3. More commonly, pain can continue once the rash resolves, a condition called post-herpetic neuralgia (PHN).

A good deal of fear surrounds this disease. Many older people have a friend of a friend who had PHN lasting for a long time. We all wish to avoid that. Some doctors define PHN as pain persisting for over a month after the onset of the disease. The benefit of this definition is that, if pain persists over a month, and we address it at that point, then patients recover more quickly and are less likely to have long-lasting pain. The downside of this definition is that the natural course of shingles includes pain lasting several months. Figures vary, but

Three months - half of people still hurt
Six months - less than a quarter
Twelve months - Less than one in twenty

Treatment of Shingles

When an anti-viral drug is started right away, we can dramatically reduce the pain and rash. It is important to start promptly. Wait over three days after the rash begins, when fresh vesicles stop appearing, and anti-virals are of questionable value. The best option these days is valacyclovir 1000 milligrams three times a day for a week. We also prescribe pain medication so people can get a good sleep at night.

The Shingles Vaccine Study

Let's talk about the recently approved vaccine. The evidence comes from an article in the New England Journal of Medicine, concerning a study1 of 38,000 people over the age of 60. Half were immunized against shingles, half were given a placebo injection. They were tracked for about three years.

Here are the results.

Immunized people Non-immunized
Total people in each group 19,254 19,247
Cases of shingles 315 642
Pain lasting more than 90 days ñ all ages 27 80
Pain lasting more than 180 days ñ all ages 9 33
Pain lasting more than 90 days ñ age 60 to 69 8 23
Pain lasting more than 90 days ñ age 70 and over 19 57

Table 1: Case-controlled study of shingles immunization

The authors did not mention whether the vaccine prevented ocular complications or scarring at the site of the rash.

The media correctly reported that the vaccine cut the incidence of shingles by about half.

To ascertain safety, researchers looked at participants for six weeks; about a third had redness at the injection site. The frequency of pain or swelling at the injection site was also about one in three. Over the whole three years of the study, investigators looked closely for side effects in about 3000 study participants. They noted no adverse effects that they could attribute to the vaccine.

 

Cost Versus Benefit of the Vaccine

Let's look again at the numbers. Of 19,000 people vaccinated, about 325 were spared having shingles over the three year period, or 1.7 %. No one knows how long the vaccine is effective. If it is effective for nine years, your chance of avoiding shingles would be about 5%.

Since the purpose of the vaccine is to avoid shingles, let's look at the costs we avoid with the vaccine. That cost can vary. Choose the generic, acyclovir, and you pay $20. You must take it five times a day. This is what I usually prescribe, and patients do quite well with it. According to the authorities, older patients may be better off with valacyclovir (Valtrex), but it costs about $200. Valacyclovir is transformed into acyclovir in the body, and thus has a longer duration of action. Pain pills might set you back $20, and three office visits (an average) about $200. If shingles involves the eyes, there will be additional cost for ophthalmologic help. (It may relieve you to know that I have never seen anyone lose vision as a result of shingles.) Let's assume a per-case cost of $500, allowing a cushion to cover complications.

If you take 38,000 people, the number in this study group, immunize half, and let nine years pass, here is your cost breakdown. About 2000 will get shingles with or without the immunization, so we'll leave them out of the figuring. About 981 people in the immunized group will avoid the shingles. The cost of treatment is greater when one is older, and I've included a larger reserve to cover the chance of specialty care if required. I have not put a number on "older" and "younger" because there are healthy seventy year olds with an immune system more robust than some fifty year olds. However, at any age, I'm estimating the cost of not getting the vaccine at between $300,000 and $700,000, in round numbers, for the 981 people. The cost of the vaccine for those same people would be over $4,000,000

Older person Younger person
Vaccine efficacy in years
9
9
Cases avoided
981
981
Total cost of care per case
$680
$300
Office visits $260 $200
Medication $220 $40
Reserve for complications $200 $60
Cost avoided with vaccine
$667,000
$294,000
Cost for vaccination (each) $215 $215
Cost for vaccination of entire group
$4,139,000
$4,138,000

Table 2: Cost of immunization vs. cost avoided

Strictly on a cost basis, the vaccine loses. Now, let's look at its advantages.

Those people who get shingles even though they've had the vaccine, have milder cases.

  • They had less PHN (See Table 1)
  • Their pain and discomfort disappeared in 21 days compared to 24 days in those without the vaccine.
  • They scored better on a "severity of illness score" (140) than did people without the vaccine (180).

Post-Herpetic Neuralgia (PHN)

Looking closely at the statistics in table 1, you can see that without the vaccine, about one person per thousand in their sixties will get shingles. Among people in their 70s, about two per thousand will get shingles.

Here's how I did the math: The odds of suffering PHN in your sixties are 4 per ten thousand with the vaccine, 12 per ten thousand without. (Look at line 5 in table 1; 8 cases of PHN [defined as pain lasting over 90 days] per 19,000 people = 4 per ten thousand). About one in a thousand people in their sixties will avoid PHN with the vaccine. (12 per ten thousand without the vaccine minus 4 per ten thousand with comes to 8 per ten thousand, or about 1 per thousand in round numbers). If a person is seventy or over, about two per thousand will avoid PHN by using the vaccine. These figures apply to the three years this study covered. Assuming the vaccine is just as effective for nine years, about six people per thousand over the age of seventy would avoid PHN with the vaccine.

Shortcomings of the Research

First, the study group was all over the age of 60. Under the age of 60 we'd expect the relative benefit to be less, since shingles is less severe at younger ages.

Second, authors of the report did not review results from a previous study2 addressing the community effects of varicella immunization. A group from Harvard Medical School surveyed residents of Massachusetts over a five year period in which varicella (chicken pox) immunization was introduced into the Massachusetts population. They found that while the incidence of chicken pox fell from 16 per thousand to 3 per thousand, that the rate of shingles rose from 3 per thousand to 5 per thousand. They theorized that our immune systems are more effective at keeping the varicella virus inactive when we are occasionally challenged by contact with chicken pox in the community. We are usually not aware of this contact, but our immune system responds by boosting its own ability to eliminate the virus. When children are prevented from developing chicken pox with the vaccine, adults become less immune to the varicella virus and are more prone to develop shingles.

The shingles vaccine used in adults is more concentrated than the varicella vaccine used in children, so we do not really know what result the immunization will have on community immunity. Nonetheless, we need to recognize that we humans have coexisted with varicella and many other microorganisms for eons. We must expect some surprises when we interfere with the system.

Finally, if we were play devil's advocate here, we'd point out that many of the authors of this study consult for, own stock in, are employed by, or otherwise receive financial support from the maker of the vaccine. Two authors have "a partial interest in relevant patents." There were two very positive editorial comments on the study in the New England Journal, one penned by someone who consults for the vaccine manufacturer.

This may be the reason that an earlier article3 in the Journal quoted the incidence of PHN at "8 to 70 percent" while an editorial4 accompanying the study reported that PHN occurred in almost half of those age 70 or older. The footnote for this latter statement references a 1957 article. Friends, as far as treatment of shingles goes, that's the dark ages. Today we have three different anti-viral drugs to abort the illness and a laundry list of other drugs and procedures to push the PHN rate far closer to 8 percent.

The article states "Antiviral therapy reduces the severity and duration of herpes zoster but does not prevent the development of postherpetic neuralgia." That makes one think antiviral therapy is of little value, but if you look at one of the references5 given for this statement, you'll find that "multiple studies have demonstrated that antiviral therapy reduces the duration of pain."

In summary, then, the issue of the Journal containing the vaccine article paints an unnecessarily gloomy picture of shingles.

The Lowdown on PHN

As far as I can tell, the facts are these. Antiviral drugs do reduce post-herpetic neuralgia without question, but they do not always reduce it adequately. The vaccine study authors point to the failures, in light of which their vaccine is more desirable. If we just look at the numbers, in people over the age of 50, pain resolved in most in twelve weeks without treatment, and by six weeks with antiviral drugs.

People can have ongoing pain following shingles. I have never seen it ruin anyone's life, but I believe those who say it can. I am pretty aggressive about treating shingles and getting people to a pain specialist if needed to prevent PHN, which may color my experience. Also, people tolerate pain to varying degrees. It may be that my practice has more stoics than other doctors' practices.

Health Decisions

Health decisions can vary depending on your point of view. For a vaccine company assuming that people are not going to promptly go to the doctor for shingles, or that the doctor will render less than optimal care, or that the population as a whole has poor immunity, or that money will be found somewhere to pay for the vaccine, or that a single executive decision to immunize everyone is superior to physicians and patients dealing wisely with shingles when it does occur, it makes sense to lobby the government to pay for this vaccine under government insurance programs. Individuals caring for their own health and paying the bills themselves might decide that the cost of an episode of herpes zoster is more bearable than the cost of the vaccine. They might want to save their money for something more valuable.

My Advice

Here's my advice. The reason that older people are more likely to suffer the shingles is that immune function declines with age, and the vaccine stimulates the white cells that guard against shingles. If you think your immune system could use some help, either because your age is over 70 or you have some chronic illness, you might be one to benefit from this vaccine. If you have any immunologic illness or are on immunosuppressive drugs, definitely ask your doctor to consider this vaccine.

My recommendation for all others is less ringing. If you don't fall into those two categories, I'd let the dust settle. The vaccine is new, and we don't know how long it will be effective or what its long-term safety will be. It prevents only half of shingles cases, while the anti-viral drugs work every time. If shingles concerns you, ask your doctor for a prescription for acyclovir or valacyclovir to keep in your freezer. Valacyclovir, by the way, comes off patent in 2009, so the price should drop considerably. If you've got an anti-viral on hand, and you come down with shingles, you can start treatment immediately, even if it is Friday evening. Then check with your doctor later to take action against pain.

Endnotes:

1 New England Journal of Medicine 2005; 352:2271

2 BioMed Central Public Health 2005; 5:68 http://www.biomedcentral.com/content/pdf/1471-2458-5-68.pdf

3 New England Journal of Medicine 2002; 347:340

4 New England Journal of Medicine 2005; 352:2344

5 New England Journal of Medicine 2002; 347:340

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Medicine for People! is published by Douwe Rienstra, MD at Port Townsend, Washington.