Herpes zoster in a normal child after varicella vaccination

Review of the United States universal varicella vaccination program: Herpes zoster incidence rates, cost-effectiveness, and vaccine efficacy based primarily on the Antelope Valley Varicella Active Surveillance Project data

In a cooperative agreement starting January 1995, prior to the FDA's licensure of the varicella vaccine on March 17, the Centers for Disease Control and Prevention (CDC) funded the Los Angeles Department of Health Services' Antelope Valley Varicella Active Surveillance Project (AV-VASP). Since only varicella case reports were gathered, baseline incidence data for herpes zoster (HZ) or shingles was lacking. Varicella case reports decreased 72%, from 2834 in 1995 to 836 in 2000 at which time approximately 50% of children under 10 years of age had been vaccinated. Starting in 2000, HZ surveillance was added to the project. By 2002, notable increases in HZ incidence rates were reported among both children and adults with a prior history of natural varicella. However, CDC authorities still claimed that no increase in HZ had occurred in any US surveillance site. The basic assumptions inherent to the varicella cost-benefit analysis ignored the significance of exogenous boosting caused by those shedding wild-type VZV. Also ignored was the morbidity associated with even rare serious events following varicella vaccination as well as the morbidity from increasing cases of HZ among adults. Vaccine efficacy declined below 80% in 2001. By 2006, because 20% of vaccinees were experiencing breakthrough varicella and vaccine-induced protection was waning, the CDC recommended a booster dose for children and, in 2007, a shingles vaccination was approved for adults aged 60 years and older. In the prelicensure era, 95% of adults experienced natural chickenpox (usually as children)-these cases were usually benign and resulted in long-term immunity. Varicella vaccination is less effective than the natural immunity that existed in prevaccine communities. Universal varicella vaccination has not proven to be cost-effective as increased HZ morbidity has disproportionately offset cost savings associated with reductions in varicella disease. Universal varicella vaccination has failed to provide long-term protection from VZV disease.

The case against universal varicella vaccination

In 1995, the United States became the first country to implement a Universal Varicella Vaccination Program. Several questions remain: Is the varicella (chickenpox) vaccine needed? Is it cost effective as a routine immunization for all susceptible children? Or is it more beneficial for the disease to remain endemic so that adults may receive periodic exogenous exposures (boosts) that help suppress the reactivation of herpes zoster (shingles). In addition, as vaccination coverage becomes widespread, does loss of immunologic boosting cause a decline in vaccine efficacy and result in a reduced period of immunity? Scientific literature regarding safety of the varicella vaccine and its associated cost-benefit analysis have often reported optimistic evaluations based on ideal assumptions. Deleterious outcomes and their associated costs must be included when making a circumspect assessment of the Universal Varicella Vaccination Program.

[Zona in children]

Herpes zoster is the clinical consequence of a late reactivation of the varicella zoster virus (VZV). It infects mainly the elderly, but pediatric cases are not uncommon. It occurs mostly in immunocompromised children, or in infancy after reactivation of latent VZV infection acquired transplacentally during intrauterine life. Rarely, herpes zoster occurs in otherwise normal children, especially following varicella during the first year of life. Clinical presentation of herpes zoster in children is identical to that of adult, with usually a benign course. The impairment of cellular and non specific immunity (Natural Killer cells) appears to have a particular role in the occurrence of herpes zoster. Treatment of the usual form comprises antiseptic measures and prevention of pruritus. In immunocompromised children, the infection is generally severe and disseminated, and can result in high rates of morbidity and mortality, thus requiring specific intravenous antiviral therapy with antiviral drugs such as acyclovir without delay. There is no single approach towards VZV infection prevention in immunocompromised hosts. Vaccination with live attenuated varicella vaccine, has proved to be efficient and safe in immunocompromised children.