Editing BCG vaccine (section)

==Adverse effects==
BCG immunization generally causes some pain and scarring at the site of injection. The main adverse effects are [[keloid]]s—large, raised scars. The insertion to the [[deltoid muscle]] is most frequently used because the local complication rate is smallest when that site is used. Nonetheless, the buttock is an alternative site of administration because it provides better cosmetic outcomes.<ref name="Tuberculosis Vaccine Development: P"/>

BCG vaccine should be given intradermally. If given subcutaneously, it may induce local infection and spread to the regional [[lymph nodes]], causing either suppurative (production of [[pus]]) or nonsuppurative [[lymphadenitis]]. Conservative management is usually adequate for nonsuppurative lymphadenitis. If suppuration occurs, it may need [[needle aspiration]]. For unresolved suppuration, [[surgical excision]] may be required. Evidence for the treatment of these complications is scarce.<ref>{{cite journal | vauthors = Cuello-García CA, Pérez-Gaxiola G, Jiménez Gutiérrez C | title = Treating BCG-induced disease in children | journal = The Cochrane Database of Systematic Reviews | volume = 2013 | issue = 1 | pages = CD008300 | date = January 2013 | pmid = 23440826 | pmc = 6532703 | doi = 10.1002/14651858.CD008300.pub2 }}</ref>

Uncommonly, breast and [[gluteal]] abscesses can occur due to haematogenous (carried by the blood) and lymphangiomatous spread. Regional bone infection (BCG [[osteomyelitis]] or [[osteitis]]) and disseminated BCG infection are rare complications of BCG vaccination, but potentially life-threatening. Systemic antituberculous therapy may be helpful in severe complications.<ref>{{cite journal | vauthors = Govindarajan KK, Chai FY | title = BCG Adenitis-Need for Increased Awareness | journal = The Malaysian Journal of Medical Sciences | volume = 18 | issue = 2 | pages = 66–69 | date = April 2011 | pmid = 22135589 | pmc = 3216207 }} [http://www.mjms.usm.my/default.asp?tag=14&kod_volume=48 Malaysian Journal of Medical Sciences] {{webarchive|url=https://web.archive.org/web/20120326140134/http://www.mjms.usm.my/default.asp?tag=14&kod_volume=48 |date=26 March 2012 }}
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When BCG is used for bladder cancer, around 2.9% of treated patients discontinue immunotherapy due to a genitourinary or systemic BCG-related infection,<ref>{{cite journal | vauthors = Nummi A, Järvinen R, Sairanen J, Huotari K | title = A retrospective study on tolerability and complications of bacillus Calmette-Guérin (BCG) instillations for non-muscle-invasive bladder cancer | journal = Scandinavian Journal of Urology | volume = 53 | issue = 2–3 | pages = 116–122 | date = 4 May 2019 | pmid = 31074322 | doi = 10.1080/21681805.2019.1609080 | s2cid = 149444603 }}</ref> however while symptomatic bladder BCG infection is frequent, the involvement of other organs is very uncommon.<ref>{{cite journal | vauthors = Liu Y, Lu J, Huang Y, Ma L | title = Clinical Spectrum of Complications Induced by Intravesical Immunotherapy of Bacillus Calmette-Guérin for Bladder Cancer | journal = Journal of Oncology | volume = 2019 | pages = 6230409 | date = 10 March 2019 | pmid = 30984262 | pmc = 6431507 | doi = 10.1155/2019/6230409 | doi-access = free }}</ref> When systemic involvement occurs, liver and lungs are the first organs to be affected (1 week [median] after the last BCG instillation).<ref>{{cite journal | vauthors = Cabas P, Rizzo M, Giuffrè M, Antonello RM, Trombetta C, Luzzati R, Liguori G, Di Bella S | title = BCG infection (BCGitis) following intravesical instillation for bladder cancer and time interval between treatment and presentation: A systematic review | journal = Urologic Oncology | volume = 39 | issue = 2 | pages = 85–92 | date = February 2021 | pmid = 33308969 | doi = 10.1016/j.urolonc.2020.11.037 | s2cid = 229179250 }}</ref>

If BCG is accidentally given to an immunocompromised patient (e.g., an infant with [[severe combined immune deficiency]]), it can cause disseminated or life-threatening infection. The documented incidence of this happening is less than one per million immunizations given.<ref name="pmid 8602127">{{cite journal | vauthors = ((Centers for Disease Control and Prevention)) | title = The role of BCG vaccine in the prevention and control of tuberculosis in the United States. A joint statement by the Advisory Council for the Elimination of Tuberculosis and the Advisory Committee on Immunization Practices | journal = MMWR. Recommendations and Reports | volume = 45 | issue = RR-4 | pages = 1–18 | date = April 1996 | pmid = 8602127 | url = https://www.cdc.gov/mmwr/PDF/rr/rr4504.pdf | access-date = 6 January 2020 | archive-date = 6 January 2020 | archive-url = https://web.archive.org/web/20200106203240/https://www.cdc.gov/mmwr/PDF/rr/rr4504.pdf | url-status = live }}</ref> In 2007, the WHO stopped recommending BCG for infants with [[Human immunodeficiency virus|HIV]], even if the risk of exposure to tuberculosis is high,<ref>{{cite journal | vauthors = ((World Health Organization)) | title = Revised BCG vaccination guidelines for infants at risk for HIV infection | journal = Weekly Epidemiological Record | volume = 82 | issue = 21 | pages = 193–196 | date = May 2007 | pmid = 17526121 | hdl = 10665/240940 | hdl-access = free }}</ref> because of the risk of disseminated BCG infection (which is roughly 400 per 100,000 in that higher risk context).<ref>{{cite journal | vauthors = Trunz BB, Fine P, Dye C | title = Effect of BCG vaccination on childhood tuberculous meningitis and miliary tuberculosis worldwide: a meta-analysis and assessment of cost-effectiveness | journal = Lancet | volume = 367 | issue = 9517 | pages = 1173–1180 | date = April 2006 | pmid = 16616560 | doi = 10.1016/S0140-6736(06)68507-3 | s2cid = 40371125 }}</ref><ref>{{cite journal | vauthors = Mak TK, Hesseling AC, Hussey GD, Cotton MF | title = Making BCG vaccination programmes safer in the HIV era | journal = Lancet | volume = 372 | issue = 9641 | pages = 786–787 | date = September 2008 | pmid = 18774406 | doi = 10.1016/S0140-6736(08)61318-5 | s2cid = 6702107 }}</ref>