Order of Live and Inactivated Vaccines and Risk of Non-vaccine-targeted Infections in US Children 11-23 Months of Age

Pediatr Infect Dis J. 2020 Mar;39(3):247-253. doi: 10.1097/INF.0000000000002550.


Background: Some findings from observational studies have suggested that recent receipt of live vaccines may be associated with decreased non-vaccine-targeted infection risk and mortality. Our objective was to estimate risk of non-vaccine-targeted infections based on most recent vaccine type (live vaccines only, inactivated vaccines only or both concurrently) received in US children 11-23 months of age.

Methods: We conducted a retrospective cohort study within the Vaccine Safety Datalink. We examined electronic health record and immunization data from children born in 2003-2013 who received 3 diphtheria-tetanus-acellular pertussis vaccines before their first birthday. We modeled vaccine type as a time-varying exposure and estimated risk of non-vaccine-targeted infections identified in emergency department and inpatient settings, adjusting for multiple confounders.

Results: Among 428,608 children, 48.9% were female, 4.9% had ≥1 immunization visit with live vaccines only and 10.3% had a non-vaccine-targeted infection. In males, lower risk of non-vaccine-targeted infections was observed following last receipt of live vaccines only or live and inactivated vaccines concurrently as compared with last receipt of inactivated vaccines only [live vaccines-only adjusted hazard ratio (aHR) = 0.83, 95% confidence interval (CI): 0.72-0.94; live and inactivated vaccines concurrently aHR: 0.91, 95% CI: 0.88-0.94]. Among females, last receipt of live and inactivated vaccines concurrently was significantly associated with non-vaccine-targeted infection risk (aHR = 0.94, 95% CI: 0.91-0.97 vs. last receipt of inactivated vaccines only).

Conclusions: We observed modest associations between live vaccine receipt and non-vaccine-targeted infections. In this observational study, multiple factors, including healthcare-seeking behavior, may have influenced results.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Age Factors
  • Communicable Diseases / epidemiology*
  • Communicable Diseases / etiology*
  • Disease Susceptibility
  • Female
  • Humans
  • Immunization Schedule
  • Incidence
  • Infant
  • Male
  • Proportional Hazards Models
  • Public Health Surveillance
  • Retrospective Studies
  • Risk Assessment
  • United States / epidemiology
  • Vaccination
  • Vaccines, Attenuated / administration & dosage
  • Vaccines, Attenuated / adverse effects*
  • Vaccines, Attenuated / immunology
  • Vaccines, Inactivated / administration & dosage
  • Vaccines, Inactivated / adverse effects*
  • Vaccines, Inactivated / immunology


  • Vaccines, Attenuated
  • Vaccines, Inactivated