Medical Error in Paediatric Vaccination: Case Report of Accidental ONCO-BCG Administration in Neonates

Background: Medication errors involving look-alike, sound-alike (LASA) vaccines remain a critical safety concern in neonatal immunization programs, particularly in tuberculosis-endemic settings. Accidental administration of ONCO-BCG, a formulation intended for intravesical cancer therapy, in place of standard neonatal BCG vaccine, poses significant risks; however, limited data exist regarding the clinical spectrum and outcomes of such incidents. Objective: This study aimed to evaluate the adverse effects, clinical management, and outcomes of neonates who inadvertently received ONCO-BCG during routine immunization, with the primary focus on cutaneous, haematological, and neurological complications, as well as overall recovery. Methods: This retrospective observational case series included all neonates (n = 26) exposed to ONCO-BCG at a tertiary care hospital in Karachi, Pakistan. Inclusion criteria comprised all infants who received the incorrect vaccine within a two-day period; those with prior immunodeficiency or incomplete records were excluded. Data was collected from patient files, laboratory results, and direct clinical observation, with outcome measures including the incidence of adverse drug reactions, laboratory abnormalities, and recovery status. Ethical approval was obtained from the institutional review board in accordance with the Helsinki Declaration. Data analysis utilized descriptive statistics with SPSS version 25, ensuring precise quantification of clinical events. Results: Sixteen neonates (61.5%) developed skin lesions, three (11.5%) experienced coagulation derangement, and one (3.8%) suffered intracranial haemorrhage; no cases of disseminated tuberculosis or mortality occurred. All affected infants received chemoprophylaxis and supportive care, achieving full clinical recovery within one year of follow-up. Conclusion: Accidental ONCO-BCG administration in neonates led to a high rate of preventable adverse events but was effectively managed with early recognition, multidisciplinary intervention, and targeted chemoprophylaxis. Rigorous medication safety protocols and staff training are vital for preventing similar errors and safeguarding paediatric patient health.