Timeliness of routine immunization in a population-based Italian cohort of very preterm infants: Results of the ACTION follow-up project

Alberto E. Tozzi, Simone Piga, Carlo Corchia, Domenico Di Lallo, Virgilio Carnielli, Valeria Chiandotto, Maria Cristina Fertz, Silvana Miniaci, Franca Rusconi, Marina Cuttini

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Abstract

Background: Although very preterm infants are recommended to receive immunizations, according to their chronological age, immunization start in these infants is often delayed.Aim To measure coverage and timeliness of routine immunizations in Italian very preterm infants and to assess determinants of delay. Methods: We followed up infants 22-31 completed weeks of gestational age discharged from intensive care. We measured the proportion of children with one dose of diphtheria-tetanus-pertussis-poliohepatitis, B-Hib vaccine (DTP-Pol-HBV-Hib), measles-mumps-rubella vaccine (MMR), conjugate pneumococcal vaccine (Pnc), conjugate meningococcal C vaccine (MenC), and varicella vaccine (Var) by 24 months. We used the Kaplan Meier method and Cox proportional hazard models to estimate the age, at immunization start and determinants of timeliness for each vaccine. Results: Data on 1102 (92.1%) children out of 1196 included in the cohort were analyzed. Immunization start by 24 months of age occurred in 95.9% of children for DTP-Pol-HBV-Hib; 84.0% for MMR; 49.7% for Pnc; 38.5% for MenC; and 4.1% for Var. Eighty-seven percent of participants received the first dose of DTP-Pol-HBV-Hib by 6 months of age, and 66.7% had their first MMR administered by 18 months. Hospitalization was associated with delay for all vaccines with the exception of MenC and Var. Maternal employment was associated with earlier immunization for MMR, Pnc, and MenC. DTP-Pol-HBV-Hib timeliness improved with increasing birthweight and paternal employment and decreased with a larger number of siblings in the household. MMR was delayed in children with cerebral palsy, and in those with a larger number of children in the household. Immunization for Pnc was delayed in children with larger number of siblings. Conclusions: Immunization start for all vaccines was considerably delayed in many very preterm infants. Public health strategies taking into account determinants of delay should be implemented to improve coverage and timeliness of vaccination in this group of infants.

Original languageEnglish
Pages (from-to)793-799
Number of pages7
JournalVaccine
Volume32
Issue number7
DOIs
Publication statusPublished - Feb 7 2014

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Premature Infants
Measles-Mumps-Rubella Vaccine
Immunization
immunization
vaccines
Haemophilus influenzae type b
Meningococcal Vaccines
Population
Vaccines
Siblings
Chickenpox Vaccine
Conjugate Vaccines
Pneumococcal Vaccines
Diphtheria
Whooping Cough
Tetanus
Cerebral Palsy
Critical Care
Proportional Hazards Models
Gestational Age

Keywords

  • Immunization
  • Immunization age
  • Immunization rate
  • Preterm infants

ASJC Scopus subject areas

  • Immunology and Microbiology(all)
  • Infectious Diseases
  • Public Health, Environmental and Occupational Health
  • veterinary(all)
  • Molecular Medicine

Cite this

Timeliness of routine immunization in a population-based Italian cohort of very preterm infants : Results of the ACTION follow-up project. / Tozzi, Alberto E.; Piga, Simone; Corchia, Carlo; Di Lallo, Domenico; Carnielli, Virgilio; Chiandotto, Valeria; Fertz, Maria Cristina; Miniaci, Silvana; Rusconi, Franca; Cuttini, Marina.

In: Vaccine, Vol. 32, No. 7, 07.02.2014, p. 793-799.

Research output: Contribution to journalArticle

Tozzi, Alberto E. ; Piga, Simone ; Corchia, Carlo ; Di Lallo, Domenico ; Carnielli, Virgilio ; Chiandotto, Valeria ; Fertz, Maria Cristina ; Miniaci, Silvana ; Rusconi, Franca ; Cuttini, Marina. / Timeliness of routine immunization in a population-based Italian cohort of very preterm infants : Results of the ACTION follow-up project. In: Vaccine. 2014 ; Vol. 32, No. 7. pp. 793-799.
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abstract = "Background: Although very preterm infants are recommended to receive immunizations, according to their chronological age, immunization start in these infants is often delayed.Aim To measure coverage and timeliness of routine immunizations in Italian very preterm infants and to assess determinants of delay. Methods: We followed up infants 22-31 completed weeks of gestational age discharged from intensive care. We measured the proportion of children with one dose of diphtheria-tetanus-pertussis-poliohepatitis, B-Hib vaccine (DTP-Pol-HBV-Hib), measles-mumps-rubella vaccine (MMR), conjugate pneumococcal vaccine (Pnc), conjugate meningococcal C vaccine (MenC), and varicella vaccine (Var) by 24 months. We used the Kaplan Meier method and Cox proportional hazard models to estimate the age, at immunization start and determinants of timeliness for each vaccine. Results: Data on 1102 (92.1{\%}) children out of 1196 included in the cohort were analyzed. Immunization start by 24 months of age occurred in 95.9{\%} of children for DTP-Pol-HBV-Hib; 84.0{\%} for MMR; 49.7{\%} for Pnc; 38.5{\%} for MenC; and 4.1{\%} for Var. Eighty-seven percent of participants received the first dose of DTP-Pol-HBV-Hib by 6 months of age, and 66.7{\%} had their first MMR administered by 18 months. Hospitalization was associated with delay for all vaccines with the exception of MenC and Var. Maternal employment was associated with earlier immunization for MMR, Pnc, and MenC. DTP-Pol-HBV-Hib timeliness improved with increasing birthweight and paternal employment and decreased with a larger number of siblings in the household. MMR was delayed in children with cerebral palsy, and in those with a larger number of children in the household. Immunization for Pnc was delayed in children with larger number of siblings. Conclusions: Immunization start for all vaccines was considerably delayed in many very preterm infants. Public health strategies taking into account determinants of delay should be implemented to improve coverage and timeliness of vaccination in this group of infants.",
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AU - Corchia, Carlo

AU - Di Lallo, Domenico

AU - Carnielli, Virgilio

AU - Chiandotto, Valeria

AU - Fertz, Maria Cristina

AU - Miniaci, Silvana

AU - Rusconi, Franca

AU - Cuttini, Marina

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N2 - Background: Although very preterm infants are recommended to receive immunizations, according to their chronological age, immunization start in these infants is often delayed.Aim To measure coverage and timeliness of routine immunizations in Italian very preterm infants and to assess determinants of delay. Methods: We followed up infants 22-31 completed weeks of gestational age discharged from intensive care. We measured the proportion of children with one dose of diphtheria-tetanus-pertussis-poliohepatitis, B-Hib vaccine (DTP-Pol-HBV-Hib), measles-mumps-rubella vaccine (MMR), conjugate pneumococcal vaccine (Pnc), conjugate meningococcal C vaccine (MenC), and varicella vaccine (Var) by 24 months. We used the Kaplan Meier method and Cox proportional hazard models to estimate the age, at immunization start and determinants of timeliness for each vaccine. Results: Data on 1102 (92.1%) children out of 1196 included in the cohort were analyzed. Immunization start by 24 months of age occurred in 95.9% of children for DTP-Pol-HBV-Hib; 84.0% for MMR; 49.7% for Pnc; 38.5% for MenC; and 4.1% for Var. Eighty-seven percent of participants received the first dose of DTP-Pol-HBV-Hib by 6 months of age, and 66.7% had their first MMR administered by 18 months. Hospitalization was associated with delay for all vaccines with the exception of MenC and Var. Maternal employment was associated with earlier immunization for MMR, Pnc, and MenC. DTP-Pol-HBV-Hib timeliness improved with increasing birthweight and paternal employment and decreased with a larger number of siblings in the household. MMR was delayed in children with cerebral palsy, and in those with a larger number of children in the household. Immunization for Pnc was delayed in children with larger number of siblings. Conclusions: Immunization start for all vaccines was considerably delayed in many very preterm infants. Public health strategies taking into account determinants of delay should be implemented to improve coverage and timeliness of vaccination in this group of infants.

AB - Background: Although very preterm infants are recommended to receive immunizations, according to their chronological age, immunization start in these infants is often delayed.Aim To measure coverage and timeliness of routine immunizations in Italian very preterm infants and to assess determinants of delay. Methods: We followed up infants 22-31 completed weeks of gestational age discharged from intensive care. We measured the proportion of children with one dose of diphtheria-tetanus-pertussis-poliohepatitis, B-Hib vaccine (DTP-Pol-HBV-Hib), measles-mumps-rubella vaccine (MMR), conjugate pneumococcal vaccine (Pnc), conjugate meningococcal C vaccine (MenC), and varicella vaccine (Var) by 24 months. We used the Kaplan Meier method and Cox proportional hazard models to estimate the age, at immunization start and determinants of timeliness for each vaccine. Results: Data on 1102 (92.1%) children out of 1196 included in the cohort were analyzed. Immunization start by 24 months of age occurred in 95.9% of children for DTP-Pol-HBV-Hib; 84.0% for MMR; 49.7% for Pnc; 38.5% for MenC; and 4.1% for Var. Eighty-seven percent of participants received the first dose of DTP-Pol-HBV-Hib by 6 months of age, and 66.7% had their first MMR administered by 18 months. Hospitalization was associated with delay for all vaccines with the exception of MenC and Var. Maternal employment was associated with earlier immunization for MMR, Pnc, and MenC. DTP-Pol-HBV-Hib timeliness improved with increasing birthweight and paternal employment and decreased with a larger number of siblings in the household. MMR was delayed in children with cerebral palsy, and in those with a larger number of children in the household. Immunization for Pnc was delayed in children with larger number of siblings. Conclusions: Immunization start for all vaccines was considerably delayed in many very preterm infants. Public health strategies taking into account determinants of delay should be implemented to improve coverage and timeliness of vaccination in this group of infants.

KW - Immunization

KW - Immunization age

KW - Immunization rate

KW - Preterm infants

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