Varicella Vaccine Is More Effective After 2 Doses

Children who receive 2 varicella vaccine doses are less likely to experience pediatric herpes zoster than children who receive one dose, according to new data.

This conclusion comes after the researchers investigated whether measles-mumps-rubella (MMR) and varicella vaccines separately or measles-mumps-rubella-varicella (MMRV) combined vaccination affected the incidence of pediatric herpes zoster.

To conduct their study, the researchers examined 199,797 children who turned 12 months of age from 2003 to 2008 and received care from one of 6 integrated health care systems. Participants who received varicella and MMR vaccines on recommended schedules were identified using ICD-9 codes.

Pediatric herpes zoster incidence was assessed via number of varicella vaccine doses and same-day MMR administration.

Overall, the researchers found that the pediatric herpes zoster incidence rates were

  • 18.6 per 100,000 person-years for children receiving a first dose of MMR plus the varicella vaccine,
  • 17.9 per 100,000 person-years for children receiving MMRV, and
  • 7.5 per 100,000 person-years for children receiving only the varicella vaccine.


The researchers also noted that pediatric herpes zoster incidence was lower after children received the second dose of the vaccine vs before the second dose.

“[Pediatric herpes zoster] incidence was not meaningfully different between the MMRV and MMR + [varicella] first-dose groups,” the researchers concluded. “Overall and within first-dose groups, [herpes zoster] incidence was lower among children receiving two varicella vaccine doses.”

—Amanda Balbi


Weinmann S, Irving SA, Koppolu P, et al. Incidence of herpes zoster among varicella-vaccinated children, by number of vaccine doses and simultaneous administration of measles, mumps, and rubella vaccine. Vaccine. 2020;38(37):5880-5884.