Sequence of Events

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  • raised area (wheal) about 8mm in size should be seen immediately after the shot.
  • The raised area will be absorbed in 20-30 minutes and you will not see anything at the site for few days
  • hardened area appears 2-3 weeks after the vaccine. It may be slightly painful to touch
  • After another 2-3 weeks, it may become soft and discharge pus leaving an ulcer which heals to form a small scab
  • At the end of 10-12 weeks, only a small scar (5-7mm) is visible, indicating a successful vaccination.
  • Occasionally a child may develop a swelling of a lymph node (gland) in the armpit after the vaccine. Nothing needs to be done if it is small (size of a pea), not discharging pus and is painless.