Tdap Frequently Asked Questions

Tdap Booster Vaccine - Frequently asked questions for healthcare professionals


What is Tdap booster vaccine?

Tdap is a tetanus (T), low dose diphtheria (d) and low dose acellular pertussis (ap) booster vaccine which protects against tetanus,diphtheria and pertussis. The childhood schedule as per the Immunisation Guidelines for Ireland from the National Immunisation Advisory Committee (NIAC) is:

  • Primary immunisation course of 3 doses of DTaP containing vaccines at 2, 4, and 6 months of age
  • A booster dose at 4‐5 years as DTaP/IPV (Tdap/IPV from 2016/2017)
  • A second low dose booster aged 12‐13 years as Tdap.

The aim is that each child should be given at least 5 doses of tetanus and diphtheria containing vaccines. (DTaP = Diphtheria, Tetanus & acellular Pertussis; IPV = inactivated polio virus)

How is Tdap booster vaccine given to adolescents?

The HSE provides Tdap vaccine to students in First year of second level schools. This vaccination programme was introduced to the schools immunisation programme in September 2011 replacing Td vaccine and has been in place in all areas nationally since 2012/2013.

Why has pertussis booster been added to the diphtheria and tetanus booster at 12 to 13 years?

NIAC recommended that children aged 12‐13 should receive a booster dose of pertussis as more cases of pertussis have been occurring in adolescents and adults due to the waning immunity that occurs over time combined with a reduction in natural boosting. In addition, 30% of adults with a cough lasting longer than 2 weeks may have pertussis and most infants and young children who contract pertussis are infected by a family member.

Are there any reasons why Tdap should not be given?

  • Tdap should not be given if there is a history of anaphylaxis to a previous dose of the vaccine or one of its constituents.
  • If there is a history of an *Arthus‐type reaction to a previous dose, a further routine or emergency booster dose of tetanus or diphtheria containing vaccines should not be given more frequently than every 10 years.

*(Very rarely a major local (Arthus) reaction occurs, involving swelling and erythema of most of the diameter of the upper arm fromshoulder to elbow. This usually begins 2‐8 hours after vaccination and is more common in adults. This resolves without sequelae. This severe reaction is usually associated with very high serum tetanus or diphtheria antitoxin levels).

  • In the event of acute severe febrile illness defer until recovery.

Note: The following are no longer considered either contraindications or precautions to pertussis vaccination. They have not been shown to cause permanent harm and are significantly less common after acellular than after whole‐ cellpertussis vaccines

  1. Temperature of more than 40.5°C within 48 hours of a previous dose of a pertussis‐ containing vaccine
  2. Hypotonic‐hyporesponsive episode within 48 hours of a previous dose of a pertussis‐ containing vaccine
  3. Seizures within 72 hours of a previous dose of a pertussis containing vaccine
  4. Persistent, inconsolable crying lasting more than 3 hours within 48 hours of a previous dose of a pertussis‐ containing vaccine.
  5. Active or progressive neurological disease.

What interval should there be between Tdap and a previous dose of a tetanus or diphtheria containing vaccine?

NIAC recommends that no interval is required between Tdap booster at 12‐13 years and any previous tetanus or diphtheria toxoid containing vaccine.

If a student has received 3 primary immunisations and 1 booster at 4‐5 years of age and also got a tetanus booster following tetanus prone injury should they get Tdap?

Yes. The student should get the Tdap booster because of the benefit of the pertussis component even if this is the sixth dose of a tetanus and diphtheria containing vaccine. NIAC  Immunisation Guidelines for Ireland recommend  that each child should be given a minimum of 5 doses of tetanus and diphtheria vaccines.

If a student has come to Ireland from another country, e.g. United States, and has had 4 primary doses of Diphtheria and Tetanus + 1 preschool booster, so already has had 5 doses should they have a 6th dose of tetanus containing vaccine?

The US recommends a Tdap at 11‐12 years, i.e. the US recommends 6 doses by 12 years. This is also the recommended in other countries. NIAC Immunisation Guidelines for Ireland recommend a minimum of 5 doses, and no maximum number of doses. Therefore, the recommendation is that they have the Tdap booster.

What advice should be given to parents regarding the need for further Td doses?

In the event of an injury, a risk assessment should be carried out in relation to the nature of injury and time since last dose of tetanus containing vaccine to determine if Td or Tetanus Immunoglobulin (TIG) is required – see Immunisation Guidelines for Ireland Tetanus Chapter 21 available at (you will be directed to the RCPI website)

Can other vaccines be given at the same time as Tdap?

Yes. Tdap is an inactivated vaccine so this can be administered at the same time as any other live (e.g. MMR) or inactivated (e.g. HPV) vaccine. They should be administered preferably in separate limbs or else in the same limb separated by at least 2.5cm (1 inch).

Can Tdap be given during pregnancy?

Tdap is recommended for pregnant women as early as possible after 16 weeks and before 36 weeks gestation to allow optimal transfer of pertussis antibodies to their baby to protect them from pertussis in the first months of life. However, Tdap can be given later in pregnancy but may not be as effective.

Does Tdap vaccine contain thiomersal?

No. Tdap vaccine does not contain thiomersal.

How safe is Tdap vaccine?

Tdap vaccine is safe and well tolerated. See reported adverse events below:

Table 1: Adverse reactions reported in clinical trials with Boostrix


System Organ Class



Adverse Reactions

Subjects aged 4 – 8 years (N=839)

Subjects aged 10 – 76 years (N=1931)

Infections and infestations


upper respiratory tract infection

upper respiratory tract infection pharyngitis

Blood and lymphatic system disorders




Metabolism and nutrition disorders




Psychiatric disorders

Very common



Nervous system disorders

Very common




somnolence headache disturbances in attention





Eye disorders




Respiratory, thoracic and mediastinal disorders




Gastrointestinal disorders


diarrhoea, vomiting, gastrointestinal disorders


gastrointestinal disorders








Skin and

subcutaneous tissue disorders



rash hyperhidrosis




Musculoskeletal and connective tissue disorders





joint stiffness

musculoskeletal stiffness

General disorders and administration site conditions

Very common Common Uncommon

injection site reactions (such as redness and/or swelling), injection site, pain, fatigue

injection site reactions (such as redness and/or swelling), malaise, fatigue, injection site pain



pyrexia (fever ≥ 37.5°C including fever > 39.0°C), extensive swelling of vaccinated limb (sometimes involving the

adjacent joint)

pyrexia (fever ≥ 37.5°C), injection site reactions (such as injection site mass and injection site abscess sterile)




pyrexia (fever > 39.0°C), influenza like illness, pain



other injection site reactions (such as induration), pain



See information at (size 219KB)


Very common (>1 in 10): Local injection site reactions (pain, redness and swelling). Common (> 1 in 100 to <1 in 10): Pyrexia, malaise, fatigue

Serious side effects are very rare


This page was added on 16 August 2022