25 Years of Varicella Vaccination Successes

The U.S. Centers for Disease Control and Prevention (CDC) vaccine advisory committee today presented an overview of a successful childhood vaccination program.

Mona Marin, M.D., with the CDC Advisory Committee on Immunization Practices, presented '25 Years of Varicella Vaccination Program in the United States: Health and Economic Impact during 1995–2019' on February 23, 2023.

Historically, varicella was considered a disease of little consequence, too mild to warrant prevention.

However, Varicella is an illness with a characteristic maculopapular, vesicular rash.

During the pre-vaccine era, varicella infected almost everyone during childhood, who accounted for more than 90% of the cases, two-thirds of the hospitalizations, and about half of the deaths, wrote researchers in a related article.

Varicella, known as chickenpox, is also highly infectious, with 61% and 100% secondary attack rates among susceptible household contacts, says the CDC.

As other causes of infectious disease burden in children in the U.S. were controlled through vaccination (e.g., measles, diphtheria, poliomyelitis), varicella assumed more importance as a preventable cause of mortality and morbidity.

Based on a documented continuing disease, the U.S. was the first country to implement a routine varicella vaccination program following the licensure of the live, attenuated varicella vaccine (VARIVAX®, Merck & Co, Inc) in 1995.

Expansion of the U.S. vaccination program to include a second VARIVAX dose led to further declines in disease incidence, outbreaks, hospitalizations, and deaths.

Twenty-five years after the introduction of the varicella vaccine, the disease has declined overall by about 97%.

An additional benefit of the varicella vaccination program is the impact on HZ.

Recent data show a lower HZ risk among healthy and immunocompromised children. This is reflected in stepwise declines in HZ incidence at the population level as the age groups became dominated by persons born during the varicella vaccination program.

Moreover, the decline in HZ incidence in children provides tentative reassurance that, over time, HZ rates will decline as vaccinated children age.

The Journal of Infectious Diseases published the unedited article in November 2022.

Note: Varivax and the HZ-prevention vaccines (Shingrix) are generally available at clinics and pharmacies in the U.S.