Varicella Vaccination Today, Lower Risk of Zoster Tomorrow

October 2, 2014

The mother of a 12-month-old says she'd rather her son have the chickenpox ("It's such a mild disease...") than be vaccinated today. Here, the pros and cons.

It is a busy Monday mid-morning, but so far you are only about 20 minutes behind schedule. As you are finishing up your 12-month-old well child exam, you hand the mother the VIS sheets and tell her the nurse will be in to give the shots. “Do you have any questions or concerns about the shots” you ask with one hand on the door handle. Then you hear the dreaded words, “Well, I have been doing a little research on the Internet and ... let's skip the chickenpox shot. That's such a mild disease; I would rather my son get chickenpox and never have to worry about a second infection. After all, doesn't infection from natural disease produce a better immune response than a vaccine?”

You pause, and then tell mom:

A. She is mistaken, the protection provided by a single dose of the chicken pox vaccine (Varivax) is equally as good as that from a mild case of wild chickenpox against a future case of varicella.

B. Before the vaccine, chickenpox killed several hundred children every year. Now the number is just a handful in the United States.

C. Your child's risk of later developing shingles is less if he gets the shot vs contracting the wild disease.

D. If your son does get the varicella vaccine combined with the MMR, he won't have to get an extra shot and there is no increased risk of side effects vs getting the MMR and varicella vaccines separately.

Mom's concerns do have some truth in them. She is right in that natural disease does provide essentially 100% protection against a future varicella infection-but at the price of exposing her child to the risks of the natural disease. Up to 95% of children developing chickenpox had a fairly benign course, if you consider 200 to 300 itchy vesicles and a couple of days of fever “benign.”  In the prevaccine era 5% to 10% did develop secondary complications including skin infections with staph or Group A strep, pneumonia, encephalitis, cerebellar ataxia, and otitis media, among others. 

Answer: C.  Your child's risk of later developing shingles is less if he gets the shot vs contracting the wild disease.

Discussion 
The incidence of zoster has decreased in children since the vaccine was introduced and studies show a protective effect of the vaccine when compared with a history of wild chickenpox. Most pre- and postlicensure studies show effectiveness of a single dose of 70% to 90%. After a second dose, effectiveness rises to more than 98%. But even a single dose seems to be very effective is preventing severe varicella disease. 

Before the introduction of varicella vaccine (Varivax) in the United States in 1995, about one hundred Americans died yearly, about half being children.  The use of the combination MMR and Varivax vaccines ProQuad (MMRV) at the 12-month visit has been shown to increase the risk of febrile seizures by about 1 in 2,500. While this is only a small bump in the overall incidence of febrile seizures (about 1 in 30) in children before the age of 6, it is an increased risk that is listed on the VIS sheet.

Varicella VIS, CDC.gov

MMRV VIS, CCD.gov

References:

Marshall, Gary S. The Vaccine Handbook (Fourth edition). West Islip, NY: Professional Communications, Incorporated; 2012.

Civen R, Chaves SS, Jumaan A, et al. The incidence and clinical characteristics of herpes zoster among children and adolescents after implementation of varicella vaccination. Pediatr Infect Dis J. 2009: 28:954-959.