Vaccination status and hepatitis A immunity in children: insights from a large-scale study in Turkey

Abstract Background Hepatitis A remains a public health concern, particularly in areas with suboptimal sanitation. Introduced in Turkey's immunization schedule in 2011, the vaccine has improved immunity; however, gaps persist, especially in older, unvaccinated children. This study examines the...

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Main Authors: Metin Yigit, Furkan Kalayci
Format: Article
Language:English
Published: BMC 2025-01-01
Series:BMC Infectious Diseases
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Online Access:https://doi.org/10.1186/s12879-025-10458-9
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author Metin Yigit
Furkan Kalayci
author_facet Metin Yigit
Furkan Kalayci
author_sort Metin Yigit
collection DOAJ
description Abstract Background Hepatitis A remains a public health concern, particularly in areas with suboptimal sanitation. Introduced in Turkey's immunization schedule in 2011, the vaccine has improved immunity; however, gaps persist, especially in older, unvaccinated children. This study examines the seropositivity rates and antibody levels in children across different vaccination statuses and age groups, and to identify gaps in immunity, particularly among children those born before the introduction of the hepatitis A vaccine in Turkey. Methods Data from 9,858 patients, collected between August 2019 and March 2024, were analyzed to evaluate the immunological response to the vaccine. Patients were categorized into four groups based on vaccination status: under-vaccinated (children 6–18 months old), single-dose vaccinated (children 18–24 months old), fully vaccinated (children over 24 months old born after March 1, 2011), and unvaccinated (born before March 1, 2011, when routine hepatitis A vaccination began). Seropositivity rates and antibody levels were measured and statistically analyzed. Results In this study, a total of 9,858 pediatric patients were assessed, with 1.1% under-vaccinated, 3.4% single-dose vaccinated, 60.5% fully vaccinated, and 35% unvaccinated. Seropositivity rates reached 93% in the fully vaccinated group, compared to 83% in the single-dose group and 63% in the unvaccinated group. Antibody titers were significantly higher in the fully vaccinated group, with statistically significant differences in seropositivity between this group and the unvaccinated group (p < 0.001). Additionally, a notable decrease in antibody levels was observed in the unvaccinated group as age increased (r = -0.365, p < 0.001). Conclusion These findings underscore the critical need for targeted interventions to close vaccination gaps, especially among older, unvaccinated children who exhibit lower immunity levels. These insights are crucial for enhancing vaccination outreach and improving public health measures against hepatitis A.
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spelling doaj-art-c4e2eaf3375340df99369c954422192e2025-01-19T12:11:48ZengBMCBMC Infectious Diseases1471-23342025-01-012511810.1186/s12879-025-10458-9Vaccination status and hepatitis A immunity in children: insights from a large-scale study in TurkeyMetin Yigit0Furkan Kalayci1Department of Pediatrics, Yildirim Beyazit University, Ankara Bilkent City HospitalDepartment of Pediatrics, Ankara Bilkent City HospitalAbstract Background Hepatitis A remains a public health concern, particularly in areas with suboptimal sanitation. Introduced in Turkey's immunization schedule in 2011, the vaccine has improved immunity; however, gaps persist, especially in older, unvaccinated children. This study examines the seropositivity rates and antibody levels in children across different vaccination statuses and age groups, and to identify gaps in immunity, particularly among children those born before the introduction of the hepatitis A vaccine in Turkey. Methods Data from 9,858 patients, collected between August 2019 and March 2024, were analyzed to evaluate the immunological response to the vaccine. Patients were categorized into four groups based on vaccination status: under-vaccinated (children 6–18 months old), single-dose vaccinated (children 18–24 months old), fully vaccinated (children over 24 months old born after March 1, 2011), and unvaccinated (born before March 1, 2011, when routine hepatitis A vaccination began). Seropositivity rates and antibody levels were measured and statistically analyzed. Results In this study, a total of 9,858 pediatric patients were assessed, with 1.1% under-vaccinated, 3.4% single-dose vaccinated, 60.5% fully vaccinated, and 35% unvaccinated. Seropositivity rates reached 93% in the fully vaccinated group, compared to 83% in the single-dose group and 63% in the unvaccinated group. Antibody titers were significantly higher in the fully vaccinated group, with statistically significant differences in seropositivity between this group and the unvaccinated group (p < 0.001). Additionally, a notable decrease in antibody levels was observed in the unvaccinated group as age increased (r = -0.365, p < 0.001). Conclusion These findings underscore the critical need for targeted interventions to close vaccination gaps, especially among older, unvaccinated children who exhibit lower immunity levels. These insights are crucial for enhancing vaccination outreach and improving public health measures against hepatitis A.https://doi.org/10.1186/s12879-025-10458-9Hepatitis A vaccinationPediatric immunizationSeropositivityAdolescent healthSeroepidemiology
spellingShingle Metin Yigit
Furkan Kalayci
Vaccination status and hepatitis A immunity in children: insights from a large-scale study in Turkey
BMC Infectious Diseases
Hepatitis A vaccination
Pediatric immunization
Seropositivity
Adolescent health
Seroepidemiology
title Vaccination status and hepatitis A immunity in children: insights from a large-scale study in Turkey
title_full Vaccination status and hepatitis A immunity in children: insights from a large-scale study in Turkey
title_fullStr Vaccination status and hepatitis A immunity in children: insights from a large-scale study in Turkey
title_full_unstemmed Vaccination status and hepatitis A immunity in children: insights from a large-scale study in Turkey
title_short Vaccination status and hepatitis A immunity in children: insights from a large-scale study in Turkey
title_sort vaccination status and hepatitis a immunity in children insights from a large scale study in turkey
topic Hepatitis A vaccination
Pediatric immunization
Seropositivity
Adolescent health
Seroepidemiology
url https://doi.org/10.1186/s12879-025-10458-9
work_keys_str_mv AT metinyigit vaccinationstatusandhepatitisaimmunityinchildreninsightsfromalargescalestudyinturkey
AT furkankalayci vaccinationstatusandhepatitisaimmunityinchildreninsightsfromalargescalestudyinturkey