TY - JOUR T1 - What is the significance of an accelerated BCG reaction in children? JF - Archives of Disease in Childhood JO - Arch Dis Child SP - 507 LP - 512 DO - 10.1136/archdischild-2022-323853 VL - 107 IS - 5 AU - Paola Villanueva AU - Laure F Pittet AU - Clare Nourse AU - Nigel Curtis Y1 - 2022/05/01 UR - http://adc.bmj.com/content/107/5/507.1.abstract N2 - You are asked to review a 7-month-old infant born in Australia who was given BCG the previous day in preparation for travel to India. Her parents have noticed a 6 mm diameter swelling at the injection site. You are aware that an accelerated response at a BCG injection site may be associated with underlying tuberculosis (TB) infection. The infant is otherwise completely well with a normal examination. You wonder whether you should investigate further.Is an accelerated local reaction following BCG vaccination in a child indicative of underlying TB (latent TB infection (LTBI) or active TB disease)?Medline (1946 to current), PubMed and Embase databases were searched in September 2021 with the search terms detailed in the online supplemental search strategy. Our systematic search identified 139 articles. Of these, 14 fulfilled the inclusion criteria of English-language publications addressing accelerated local reaction to intradermal BCG for diagnosing TB in children under 18 years of age. All the studies reported sensitivity but only seven included controls enabling specificity to be calculated.Supplementary data [archdischild-2022-323853supp003.pdf] BCG is one of the most extensively used vaccines worldwide, given to children to protect against TB since 1921. It has received more recent attention for its beneficial off-target effects on the immune system, associated with protection against other diseases.1 The normal reaction to intradermal BCG vaccination is the appearance of a small, red papule or swelling at the injection site within 2–3 weeks. Usually, the papule softens, resulting in a small ulcer, healing over several weeks to months into a small flat scar.2 3 In some individuals, an ‘accelerated local reaction’ occurs, commonly defined as the early development of an induration or swelling of 5 mm or more at the injection site, beginning within 24–72 hours of vaccination.4–6 An accelerated BCG reaction has also been called a ‘positive BCG … ER -