What's the Chickenpox Vaccine's Link to the Shingles Upswing?

Results of a new study suggest that the pediatric varicella zoster virus (VZV) vaccination is not the reason for the increasing incidence of herpes zoster (HZ) cases in the United States. The findings should reassure parents and pediatricians about the safety of administering the chickenpox vaccine to children.

The results were published in a December 3, 2013, article in the Annals of Internal Medicine.¹ The study's authors reviewed Medicare claims data from 1992 to 2010 encompassing more than 2.8 million people older than 65 years. They found that while the annual rate of HZ increased 39% over the 18 years the data cover, there was "no evidence of a statistically significant change in the rate of increase after introduction of the varicella vaccination program." Moreover, they found that the overall incidence of HZ cases did not differ significantly from state to state between 1997 and 2010, despite that states have differing rates of VZV vaccination coverage.

The authors — led by Centers for Disease Control and Prevention medical epidemiologist Craig M. Hales, MD, MPH — conclude that the U.S. incidence of HZ had increased among the over-65 age group before implementation of the childhood VZV vaccination program, and that the "introduction and widespread use of the vaccine did not seem to affect this increase."

When a person, usually a young person, is infected with VZV and develops chickenpox, the virus lies dormant in the body for years or even decades; reactivation of the virus leads to the development of painful HZ, or shingles. The 1996 introduction of universal varicella vaccination for U.S. children led to concerns that children's less-frequent exposure to the virus would decrease external boosting of immunity to it, thereby leading to a higher incidence of HZ later in life.

The findings are reassuring for countries that are considering universal varicella vaccination, they write.

—Michael Gerchufsky

Reference:

1. Hales CM, Harpaz R, Joesoef R, Bialek SR. Examination of links between herpes zoster incidence and childhood varicella vaccination. Ann Intern Med. 2013;159(11):739-745.  

(Photograph courtesy of Alexander K. C. Leung, MD, and Matthew C. K. Choi, MD)

More on Chickenpox from Consultant for Pediatricians:

• Varicella, "Photoclinic" article by John Harrington, MD

• Chickenpox Rates Down Since 2-Dose Vaccination Program Began, online exclusive article 

• Vaccine-Induced Herpes Zoster, "Photoclinic" article by Julie L. Cantatore-Francis, MD, and Yelva Lynfield, MD

• Case in Point: Herpes Zoster Meningitis, by Elizabeth K. Olivera, MD, and Michael Lasser, MD

• Complications of Chickenpox, by F. Hall Reynolds II, MD

• Keloid at the Site of a Chickenpox Lesion, "Photoclinic" article by Alexander K. C. Leung, MD, and Wm. Lane M. Robson, MD