BCG vaccine is highly effective against prevention of tuberculosis. It is generally a safe vaccine, however, few mild to severe adverse effects may occur rarely: - pain and discharge at injection site - fever - headache - swollen lymph nodes - abscess - TB infection - scarring - osteomyelitis - crusty scab formation - anaphylactic shock Reference: https://www.nhs.uk/conditions/vaccinations/bcg-tb-vaccine-side-effects/ Image via: https://www.tandfonline.com/doi/pdf/10.4161/hv.19067