Abstract
Vaccines may cause adverse events ranging from mild reactions like fever to serious events like seizures. Both the vaccine product and the process of vaccination can cause adverse events. Non-sterile abscesses are usually a program error (an event caused by an error in the transportation, storage, handling, or administration of a vaccine) that may occur due to contamination of a multi-dose vial. Sterile abscess may occur as a delayed hypersensitivity reaction due to the presence of aluminium salt as an adjuvant in the vaccine, and are classified as vaccine product related reactions. The Hepatitis B vaccine is recommended for all infants at birth and for children up to 18 years. Here, authors report a case of sterile abscess in an eight-month-old baby, after the administration of first dose of Hepatitis B Vaccination, possibly due to an error and hence classified as Immunisation error related reaction.