Peer-reviewed article
Immunization Gaps Among High-Risk Preterm Infants in Kazakhstan.
Balzhan N Tatibekova, Daniel Yakubovich, Ademi K Sagatbayeva, Aigul A Ismailova ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This study examined vaccination coverage in 331 preterm infants in Kazakhstan over a 10-year period and found major immunization gaps. By 24 months of age, only 34% of the high-risk preterm infants were fully vaccinated, while 50% remained completely unvaccinated. During the study, 30 measles cases and 17 pertussis cases occurred in the cohort, with serious complications including subacute sclerosing panencephalitis, hearing loss, and pneumonia. The gaps were caused by prolonged medical exemptions after discharge, parental concerns, and poor coordination between specialized neonatal services and primary health care.
Key points
- 78.2% of high-risk preterm infants had not received BCG or hepatitis B vaccine by hospital discharge
- By 24 months, only 34.1% were fully vaccinated according to age; 49.8% remained completely unvaccinated
- 30 measles cases and 17 pertussis cases occurred during the observation period, primarily during nationwide outbreaks
- Among 10 children with measles before 12 months, 2 developed subacute sclerosing panencephalitis, 1 developed profound hearing loss, and 1 required prolonged oxygen therapy
- Barriers included prolonged temporary medical exemptions, clinical caution, parental concerns, and fragmented coordination between specialized follow-up services and primary health care
Limitations
This is an observational cohort study from a single specialized center in Astana, so findings may not represent all preterm infants in Kazakhstan or other settings. The study identifies associations and barriers but cannot definitively establish causation for why immunization gaps occurred or which interventions would be most effective.
Abstract
BACKGROUND: Advances in neonatal intensive care in Kazakhstan have improved the survival of preterm infants, including those with very low birth weight (VLBW) and extremely low birth weight (ELBW). However, after hospital discharge, these medically vulnerable children may remain insufficiently protected against vaccine-preventable infections because of prolonged temporary medical exemptions, clinical caution, parental concerns, and fragmented coordination between specialized follow-up services and primary health care. OBJECTIVE: This study aimed to assess vaccination coverage in a 10-year cohort of high-risk preterm infants and to identify clinical, parental, and organizational factors associated with delayed immunization. METHODS: We conducted a retrospective cohort study of 331 high-risk preterm infants followed at a specialized pediatric center in Astana, Kazakhstan, between 2015 and 2024. Vaccination status at hospital discharge and at 24 months of chronological age, documented temporary medical exemptions, reasons for delayed or missed vaccination, and confirmed cases of pertussis and measles were analyzed. A supplementary cross-sectional survey of parents, physicians, and health care managers was conducted to further explore barriers to catch-up immunization. RESULTS: At hospital discharge, 259 infants (78.2%) had not received the BCG or hepatitis B vaccine. By 24 months of age, 34.1% (n = 113) were fully vaccinated according to age, whereas 49.8% (n = 165) remained completely unvaccinated. During the observation period, 30 cases of measles and 17 cases of pertussis were recorded within the cohort, primarily during nationwide outbreaks. Among the 10 children with a history of measles before 12 months of age, 2 developed subacute sclerosing panencephalitis (SSPE), 1 developed profound hearing loss, and 1 required prolonged oxygen therapy following pneumonia. In addition, 2 children with periventricular leukomalacia (PVL) experienced clinical deterioration, while 1 infant with pertussis required hospitalization during the acute phase of illness. CONCLUSION: High-risk preterm infants in this cohort experienced substantial and persistent gaps in immunization after hospital discharge. These findings underscore the importance of regular reassessment of temporary medical exemptions, improved coordination between specialized follow-up services and primary health care, and strengthened catch-up immunization strategies for medically vulnerable children.