Chronically ill adolescents are also incompletely vaccinated: A cross-sectional study in France.

Background: Adolescent vaccination coverage tends to be suboptimal, leading to resurgent infectious pathologies and vulnerability to various pathogens. The low frequency of medical consultations and missed opportunities for vaccination are often used to explain the low rate of vaccination. The aim of this study was to assess if the vaccination coverage rate is higher in chronically ill adolescents (CIA) who require a close pediatric specialized follow-up versus the rate in healthy adolescents (HA).

Methods: A monocentric cross-sectional study was conducted in the Nantes University Hospital. We included 114 CIA and 266 HA. The vaccination coverage rate and the up-to-date immunization status were compared between ill versus healthy adolescents for each of the following vaccines: diphtheria, tetanus, acellular pertussis, inactivated poliovirus (DTaP/IPV), measles-mumps-rubella (MMR), hepatitis B (HepB), meningococcal C conjugate (MnC), human papillomavirus (HPV) and composite combinations (e.g. DTaP/IPV-MMR-HepB-MnC).

Results: The overall immunization rate for DTaP/IPV-MMR-HepB-MnC was very low, with no significant difference between CIA and HA (9.6% versus 13.5%; p=0.28). Most of the investigated vaccines exhibited similar immunization patterns for the two groups: DTaP/IPV (77.2vs. 76.7%; p=0.97), MMR (92.1vs. 95.9%; p=0.14), HepB (51.8vs. 48.5%; p=0.51) with the exception of the MnC (18.4vs. 27.8%; p=0.05) and HPV (28.6vs. 16.1%; p=0.04).

Conclusion: Despite undergoing specialized and close medical follow-up, we found that the vaccination coverage rate for the CIA remained suboptimal. This indicates that pediatricians need to check the vaccination status and, when required, ensure that the vaccination schedules for these fragile patients are up-to-date.