The chickenpox vaccine was not available in the US for routine use until 1995, given to children at 12 months of age. This expanded to a 2 dose-series in 2005.[i] For many of us born before the vaccine's release, we may recall the "chicken-pox parties" to intentionally expose ourselves, oatmeal baths for comfort and the pockmarks worn like a badge of honor. Many wonder why we should even bother with the chickenpox vaccine.
Amidst all the stories of mild illness, chicken pox was responsible for severe illness as well. Varicella virus can cause pneumonia. Some children will suffer from a bacterial infection of their skin due to the itchy rash. And if a young child brings home the virus to their pregnant mother, the developing baby can have severe birth defects if the mother is infected[ii]. It is estimated that more than 11,000 otherwise healthy children were hospitalized every year from chicken pox before routine vaccination. And as many as 150 people died every year from varicella[iii]. For pregnant women infected before 20 weeks gestation, 2% of their babies would have congenital varicella syndromeii.
Another tricky aspect of infection with varicella is that the virus can travel to our nerve roots and remain there for decades. This "latent" varicella virus than reactivates later in life to cause the condition we call herpes zoster or "shingles." Shingles causes severe pain and rash along the nerve root where the virus lives. Adults who get shingles can have pain for a long time after the virus goes awayii. It is still possible to get shingles even after vaccination with varicella vaccine, but it seems to be less common compared with people who had chickenpox infection[iv],[v]. Shingles cases increase significantly after the age of 50. So we may not be able to see the true impact of chicken pox vaccination in the prevention of shingles until 2045 and beyond.
But we know that chicken pox vaccine has been a safe and effective way to prevent infection in childhood – and fewer kids with a miserable itchy rash, fewer hospitalizations and fewer deaths from this virus is a definite win!
[i] Centers for Disease Control and Prevention. Epidemiology and Prevention of Vaccine-Preventable Diseases. Hall E., Wodi A.P., Hamborsky J., et al., eds. 14th ed. Washington, D.C. Public Health Foundation, 2021. Available online at: https://www.cdc.gov/pinkbook/hcp/table-of-contents/index.html
[ii] 2024. "Varicella-Zoster Virus Infections", Red Book: 2024–2027 Report of the Committee on Infectious Diseases, Committee on Infectious Diseases, American Academy of Pediatrics, David W. Kimberlin, MD, FAAP, Ritu Banerjee, MD, PhD, FAAP, Elizabeth D. Barnett, MD, FAAP, Ruth Lynfield, MD, FAAP, Mark H. Sawyer, MD, FAAP
[iii] Roger Baxter, Trung N. Tran, Paula Ray, Edwin Lewis, Bruce Fireman, Steve Black, Henry R. Shinefield, Paul M. Coplan, Patricia Saddier; Impact of Vaccination on the Epidemiology of Varicella: 1995–2009. Pediatrics July 2014; 134 (1): 24–30. 10.1542/peds.2013-4251
[iv] Jessica Leung, Kathleen Dooling, Mona Marin, Tara C Anderson, Rafael Harpaz, The Impact of Universal Varicella Vaccination on Herpes Zoster Incidence in the United States: Comparison of Birth Cohorts Preceding and Following Varicella Vaccination Program Launch, The Journal of Infectious Diseases, Volume 226, Issue Supplement_4, 1 November 2022, Pages S470–S477, https://doi.org/10.1093/infdis/jiac255
[v] Weinmann S, Naleway AL, Koppolu P, Baxter R, Belongia EA, Hambidge SJ, Irving SA, Jackson ML, Klein NP, Lewin B, Liles E, Marin M, Smith N, Weintraub E, Chun C. Incidence of Herpes Zoster Among Children: 2003-2014. Pediatrics. 2019 Jul;144(1):e20182917. doi: 10.1542/peds.2018-2917. Epub 2019 Jun 10. PMID: 31182552; PMCID: PMC7748320.
