Pediatric invasive meningococcal disease in Türkiye during the post-pandemic period: increased reported cases and predominance of serogroup B and severity determined by a clinical form in a multicenter hospital-based cohort.

Authors

Esra Cakmak Taskin, Gul Arga, Basak Ceren Arslan, Isil Ezel Taskin Karacay, Mustafa Genceli, Emine Hafize Erdeniz, Ozge Kaba, Gulhadiye Avcu, Sevgi Kus, Meryem Cagla Abaci Capar, Behiye Benaygul Kacmaz, Gulsum Alkan, Sevgi Yasar Durmus, Aysenur Bostan, Ayse Kubra Acik, Fatma Dilsad Aksoy, Taylan Celik, Mehlika Efendi Kocagoz, Dicle Sener Okur, Ayse Tekin Yilmaz, Erdem Oksuzoglu, Damla Seyhanli, Nahide Gokay, Nesli Agrali Eroz, Hatice Sinav Utku, Cihangul Bayhan, Canan Ozlu, Sibel Lacinel Gurlevik, Murat Sutcu, Mahmut Can Kizil, Emel Celebi Congur, Zuhal Umit, Aslihan Sahin, Burcu Bursal, Tugba Kandemir Gulmez, Meryem Baysal, Eda Sahin Izci, Fatma Kilinc, Yasemin Ersozlu, Melis Deniz, Neslihan Mete Atasever, Nermin Celik, Cansu Turan, Alper Cicek, Ali Korulmaz, Aysun Yahsi, Edanur Yesil, Ahu Kara Aksay, Semra Bayturan, Umit Celik, Aslinur Ozkaya Parlakay, Ozge Metin Akcan, Halil Ozdemir, Dilek Yilmaz, Zumrut Sahbudak Bal, Adem Karbuz, Melike Emiroglu, Tugce Tural Kara, Nursen Belet, Omer Kilic, Selim Oncel, Sevgen Tanir Basaranoglu, Ayse Buyukcam, Gulsen Akkoc, Ayper Somer, Nazan Dalgic, Salih Demirhan, Binnaz Celik, Ilknur Kaleli, Irem Ersayoglu, Mehmet Ozgur Arslanoglu, Ayse Tolunay Oflu, Erennur Tufan, Ismail Zafer Ecevit, Zafer Kurugol, Ener Cagri Dinleyici, Hasan Tezer, Ates Kara, Ergin Ciftci

Published in

European journal of pediatrics. Volume 185. Issue 10. Sep 28, 2026. Epub Sep 28, 2026.

Abstract

Invasive meningococcal disease (IMD) remains a major cause of morbidity and mortality in children. Post-pandemic epidemiological patterns of pediatric IMD are not well defined in Türkiye. This study aimed to evaluate the epidemiology, clinical characteristics, outcomes, and serogroup distribution of pediatric IMD in a large multicenter cohort in Türkiye, comparing the during-COVID and post-COVID periods. This retrospective multicenter hospital-based study included children aged 1 month-18 years hospitalized with laboratory-confirmed IMD in 39 hospitals across 23 provinces. Cases were grouped as during-COVID (January 2020-May 2022) and post-COVID (June 2022-December 2025). A total of 166 patients (median age 25 months; 59.6% male) were included; 25 occurred during-COVID and 141 post-COVID. The number of reported cases in participating centers increased after 2022, with seasonal peaks in winter and early spring. Children under 5 years accounted for 62.7% of cases, and infants (< 1 year) were the largest single age group overall (38.6%). The proportion of children under 5 years was lower in the post-COVID period (58.9% vs 84.0%; OR 0.27, 95% CI 0.09-0.84), indicating a relative shift toward older age groups rather than a reduction in disease burden among infants. Pediatric intensive care admission occurred in 69.9% of cases, and overall mortality was 13.3%. Mortality varied markedly by clinical form, from 1.2% in meningitis alone to 21.7% in combined meningitis and meningococcemia and 38.1% in meningococcemia alone (p < 0.001). Only 2.4% of children had received any meningococcal vaccine before their illness. Serogroup data were available for 60.8% of patients, with grouping coverage differing between periods (32.0% vs 66.0%). Among cases with available serogroup data, serogroup B accounted for 69.9% in the post-COVID period and for half of the eight grouped cases during the pandemic. In unadjusted exploratory analysis restricted to cases with serogroup data, mortality was higher in serogroup B than non-B infections (21.7% vs 3.1%; OR 8.61, 95% CI 1.08-68.8); in an exploratory model adjusting for clinical form, age, and period, with ungrouped cases retained as a separate category, serogroup B remained associated with mortality (aOR 7.59, 95% CI 1.55-75.65).
In this multicenter hospital-based cohort, reported pediatric IMD cases increased in the post-pandemic period, with a persistent burden in infants, a relative shift toward older age groups, and predominance of serogroup B among grouped cases. These findings highlight the importance of strengthened surveillance and support further evaluation of meningococcal vaccination strategies, including MenB vaccination.
• Invasive meningococcal disease remains a severe pediatric infection with high morbidity and mortality, despite treatment. • The COVID-19 pandemic and the subsequent easing of restrictions altered IMD epidemiology globally.
• Reported pediatric IMD cases increased in the post-pandemic period, with a relative shift toward older children while the proportion of infants remained unchanged (38.3% vs 40.0%); serogroup B predominated among cases with an available serogroup result, although differential availability of these data precludes conclusions about change over time. • Mortality was determined principally by clinical form, ranging from 1.2% in meningitis alone to 38.1% in meningococcemia alone, and only 2.4% of children had received any meningococcal vaccine before their illness.

PMID:
42802197
Bibliographic data and abstract were imported from PubMed on 28 Sep 2026.

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