Cakupan Imunisasi Dasar Lengkap (IDL) di Kabupaten Lebak tahun 2023 terjadi ketidakmerataan, dimana (39,5%) 17 Puskesmas di wilayah kerja Dinas Kesehatan Kabupaten Lebak tidak mencapai target cakupan Imunisasi Dasar Lengkap (IDL) dari target Nasional yaitu sebesar 100%.
Penelitian menggunakan pendekatan kualitatif dengan desain studi kasus yang dilaksanakan di dua puskesmas dengan cakupan Imunisasi Dasar Lengkap (IDL) tertinggi dan terendah di Kabupaten Lebak. Jumlah informan dalam penelitian ini yaitu enam informan. Pengumpulan data dilakukan dengan wawancara mendalam dan observasi melalui telaah dokumen, kemudian dilakukan analisis data kualitatif.
Penelitian menunjukkan bahwa cakupan Imunisasi Dasar Lengkap (IDL) berkaitan dengan pelayanan kesehatan, sumber daya manusia, logistik vaksin, pembiayaan, pencatatan pelaporan, penggerakan pelaksanaan serta pengawasan pengendalian penilaian. Sehingga dapat disimpulkan kinerja program imunisasi terhadap cakupan Imunisasi Dasar Lengkap (IDL) di Kabupaten Lebak tahun 2023 masih menghadapi beberapa tantangan utama yang berdampak pada ketidakmerataan cakupan Imunisasi Dasar Lengkap (IDL).

The coverage of Complete Basic Immunization (CBI) in Lebak Regency in 2023 was uneven, where (39.5%) 17 Health Centers in the working area of the Lebak Regency Health Office did not achieve the target of Complete Basic Immunization (CBI) coverage from the National target of 100%.  The study used a qualitative approach with a case study design carried out in two health centers with the highest and lowest Complete Basic Immunization (CBI) coverage in Lebak Regency. The number of informants in this study was six informants. Data collection was carried out through in-depth interviews and observations through document review, then qualitative data analysis was carried out.  The study shows that the coverage of Complete Basic Immunization (CBI) is related to health services, human resources, vaccine logistics, financing, reporting records, implementation mobilization and supervision of assessment control. So it can be concluded that the performance of the immunization program on the coverage of Complete Basic Immunization (CBI) in Lebak Regency in 2023 still faces several major challenges that have an impact on the uneven coverage of Complete Basic Immunization (CBI).