using paracetamol to prevent and treat fever after MenB vaccination

Paracetamol to prevent and treat fever after MenB vaccination

Fever can be expected after any vaccination, but is more common when the MenB vaccine (Bexsero) is given with the other routine vaccines at 8 and 12 weeks

• without paracetamol, more than half of infants will develop a temperature after these vaccines
  
  
• fever tends to peak around 6 hours after vaccination and is nearly always gone completely within 2 day
  • total of 3 doses of 2.5ml (60mg) of paracetamol are recommended following MenB vaccination
  • first should be given dose at the time of vaccination or as soon as possible afterwards
  • the second dose of paracetamol should be given around 4 to 6 hours later and a third dose 4 to 6 hours after that
  • for very premature babies (born before 32 weeks gestation), paracetamol should be prescribed according to the infant’s weight at the time of vaccination
    
    
• giving paracetamol soon after vaccination – and not waiting for a fever to develop – will reduce the risk of your child having a fever.
  • with paracetamol, fewer than 1 in 5 children will get a fever and nearly all of these are mild (below 39°C)
  • paracetamol will also reduce the chance pain at the site of the injection
  • paracetamol is not routinely needed after the Men B booster vaccine given at 12 months of age
    • by this age the baby’s risk of fever is the same as after other vaccines

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Notes:

• paracetamol is approved for managing fever in children from the age of 2 months
• as fever after vaccination is common, experts have advised that it is OK to give paracetamol for up to 48 hours after the MenB vaccine without seeking medical advice (1)
  • fever in this time period is much more likely to be caused by the vaccine than by an infection

Reference:

1. UK Health Security Agency (June 2025). Using paracetamol to prevent and treat fever after MenB vaccination