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6-in-1 vaccine: side effects

The 6-in-1 vaccine is very safe but, as with all medicines, a few babies will have side effects. In general, side effects are mild and short-lived. Most babies will not have any problems at all.

Common reactions to the 6-in-1 vaccine

The side effects that are most often reported after the 6-in-1 vaccine, in up to 1 in 10 babies, are:

  • pain, redness and swelling at the injection site
  • fever (high temperature above 38C) – more common at the second and third dose
  • vomiting
  • abnormal crying
  • irritability
  • loss of appetite

Rare side effects after the 6-in-1 vaccine

Other possible, but much rarer, side effects – reported in fewer than 1 in 10,000 babies – include:

  • unusual high-pitched crying
  • fits or seizures

Allergic reaction to the 6-in-1 vaccine 

Very rarely, a baby will have a severe allergic reaction (anaphylaxis) after the 6-in-1 vaccine. This happens in fewer than 1 in 100,000 cases, and it can happen with any vaccine.

Anaphylaxis is a serious medical condition, but all vaccination staff are trained to deal with anaphylactic reactions on the spot. Babies treated promptly make a good recovery.

What to do if your baby gets a fever (high temperature)

If your child develops a fever (high temperature) after their 6-in-1 vaccination, keep them cool by:

  • making sure they do not have too many layers of clothes or blankets on
  • offering extra drinks (if you are breastfeeding, your child may feed more often)

You could also give them infant paracetamol to reduce their temperature. Read more about medicines for children.

Call your GP surgery or 111 if:

  • your baby is under 3 months old and has a temperature of 38C or higher, or you think they have a high temperature
  • your baby is 3 to 6 months old and has a temperature of 39C or higher, or you think they have a high temperature
  • you're worried about your baby

What to do if your baby has a serious side effect

See a doctor if your baby is very unwell or you're concerned in any way about their health following a vaccination.

If your baby has a fit or any serious medical problem once they're home after their vaccination, call the GP or call 999 for an ambulance immediately.

Seizures can look very alarming, but babies usually recover from them quickly.

If you are concerned about how your baby reacted to a previous dose of the 6-in-1 vaccine, talk to the GP, practice nurse or health visitor.

Read more about vaccine side effects in babies

This NHS leaflet tells you the common vaccination reactions in babies and young children up to 5 years old (PDF, 118kb).

Read Is vaccination safe? to find out more.

Monitoring safety of the 6-in-1 vaccine

In the UK, the safety of vaccines is monitored through the Yellow Card Scheme by the Medicines and Healthcare products Regulatory Agency (MHRA) and the Commission on Human Medicines.

Most reactions to the 6-in-1 vaccines reported through the Yellow Card Scheme have been minor, such as a rash, high temperature, vomiting, redness or swelling at the site of the injection.

Find out how to report a vaccine side effect.

Page last reviewed: 11 June 2019
Next review due: 11 June 2022