Pertussis in Pregnancy

Tdap Vaccination during Pregnancy - Frequently Asked Questions

 

 

Why is it important to protect against pertussis with childhood and maternal vaccination?

Pertussis (whooping cough) is a serious illness, especially in young children. Young infants are at highest risk of severe complications. The best way to protect against pertussis is vaccination of infants, children and pregnant women.

 

When is the Pertussis vaccine recommended?

In Ireland, pertussis containing vaccines are offered as part of national immunisation programmes.

Babies born before the 30th of September 2024 are offered the following:

  • Childhood immunisation at 2, 4, and 6 months of age with the 6 in 1 vaccine
  • As part of the school immunisation programme children are offered:
    • Booster 1 (4 in 1) in Junior Infants
    • Booster 2 (Tdap) in first year of secondary school

As part of the new primary immunisation schedule, babies born on or after 1 Oct 2024 will be offered the above pertussis containing vaccines plus an additional dose in the 6 in 1 vaccine at 13 months.

 

Is the whooping cough vaccine recommended in pregnancy?

The pertussis vaccine (Tdap) is recommended during each pregnancy.

 

When in pregnancy is the pertussis vaccine (Tdap) recommended?

The vaccine is recommended between 16 and 36 weeks of pregnancy. Maternal immunisation results in passive antibody transfer to the baby. Getting the vaccine means pregnant women will be protected against whooping cough, and this vital immunity passes to the baby in utero through passive antibody transfer. This will protect the infant from birth when they are too young to be vaccinated or fully vaccinated.

 

How common is pertussis?

 Pertussis is common in Ireland and in many developed countries. The number of cases reported varies year to year with periodic outbreaks. Cycles of increased pertussis typically occur every five years.

As of 23 November, there have been 620 cases of pertussis in 2024 in Ireland including 478 confirmed, 78 probable and 64 possible cases. This is compared with very low numbers in recent years during the COVID-19 pandemic (2021 – 5 cases, 2022 – 7 cases, 2023 – 18 cases).

Pertussis cases occur throughout the year, with the highest number of cases typically seen between May and August.   Increased circulation is expected to continue in 2025.

Pertussis continues to be reported in babies less than 6 months of age who are at highest risk of complications (and too young to be fully vaccinated).

 

Who is susceptible to pertussis infection?

Currently, the highest incidence, morbidity and mortality occur in infants, particularly in those aged less than 6 months. Babies less than 6 months of age are too young to be fully vaccinated. Complications of pertussis infection and hospitalisation are significantly more frequent in infants. 50% of infected infants (< 1 year of age) will require hospitalisation.

 

Why has there been an increase in pertussis cases in recent years?

The increase in cases is thought to be due to the fact that the immunity produced from acellular pertussis vaccines is not as long‐lasting and the immune response may not be as good as with the previously used whole cell vaccine.

In recent years there has been an increase in cases among adolescents and adults. This change in the epidemiology of pertussis is due to the waning immunity that occurs after both disease and vaccination, and to a reduction in natural boosting. There may also be a change in the characteristics of the organism, although no vaccine-resistant mutants have been identified.

Pertussis vaccination or previous infection does not confer lifelong immunity. Immunity wanes over time so people can be reinfected and spread the infection to others. Current pertussis vaccines provide good short term immunity but require boosting.

 

Who is most at risk of whooping cough?

Pertussis can occur at any age, but the most commonly diagnosed age groups are infants under one year of age who are at highest risk of complications, and adolescents. However, an increasing number of adults are being diagnosed with pertussis.

As a general rule, all people who have not completed their immunisation schedule are at risk of contracting the disease. In addition, immunisation wanes over time, so it is possible to have whooping cough more than once in a lifetime. (ECDC webpage https://www.ecdc.europa.eu/en/pertussis-whooping-cough)

 

Why is it so important that those recommended the pertussis vaccine receive it on time?

Pertussis can lead to complications such as:

  • pneumonia
  • ear infection
  • dehydration
  • apnoea in infants
  • seizures
  • brain disorders
  • hernias

Severe cases can lead to death. Infants are most at risk of severe complications and death.

Maternal vaccination means pregnant women will be protected against whooping cough, and this vital immunity passes to the baby in utero and will protect their newborn baby from birth during their earliest, most vulnerable months before they can be vaccinated themselves.

 

How effective is maternal vaccination against pertussis?

Maternal vaccination is 90% effective in preventing pertussis infection and 97% effective against infant death from pertussis.

 

Why is pertussis vaccine recommended for pregnant women?

Pertussis vaccine (Tdap) is recommended for pregnant women to reduce the risk of infection in the mother and to reduce the morbidity and mortality in infants too young to be vaccinated. Tdap vaccination during pregnancy provides passive protection to newborn infants through transplacental transfer of antibody to protect them in the early weeks after birth. 

 

Why is pertussis vaccination during pregnancy important for the new born infants?

Pertussis or whooping cough is highly infectious, and infants under the age of 6 months are most at risk of complications.

Of those hospitalised with pertussis infection

  • 50% of infected infants will develop apnoea
  • 20% develop pneumonia
  • 1% will have seizures
  • 1% will die

(National Immunisation Advisory Committee, 2018)

important:

Babies under 6 months of age are most likely to be hospitalised with pertussis

 

What is the Tdap booster vaccine?

Tdap is a tetanus (T), low dose diphtheria (d) and low dose acellular pertussis (p) booster vaccine which protests against tetanus, diphtheria and pertussis infection.

 

Is the Tdap vaccine free during pregnancy?

The Tdap vaccine is obtained free of charge from the National Cold Chain service for pregnant women. Reimbursement of GPs for administering the Tdap vaccine in pregnancy is available through an outbreak code (contact PCERS for details). 

 

When should pregnant women be vaccinated?

Pregnant women should be offered Tdap vaccine between 16 – 36 weeks gestation in each pregnancy.

Tdap may be administered at any time in pregnancy after 36 weeks gestation if it has not been given earlier. Vaccine given after 36 weeks gestation will be less effective in providing passive protection to the new born, but should protect the mother from pertussis infection and therefore she will not be a source of pertussis infection for her baby.

 

Why is Tdap recommended in each pregnancy?

This is on the basis of data showing that maternal antibodies to pertussis wane and so will not provide protection for newborn infants in subsequent pregnancies.

 

When is whooping cough vaccine recommended for those who come in contact with premature babies born before 32 weeks?

Preventing pertussis in infants by immunising their close contacts-parents, siblings, grandparents, childcare providers, and health care workers is advised for infants born before 32 weeks gestation as they may not have received protection via maternal antibody transfer.

Tdap should be offered to all unvaccinated close adult contacts who have not had a pertussis vaccine in the previous 10 years. Ideally, the vaccine should be given at least 2 weeks before beginning close contact with the infant.

Children under 10 years should receive full dose pertussis vaccine as DTaP/IPV/Hib/Hep B (6 in 1) or DTaP/IPV (4 in 1).

Those aged 10 years and over should receive low dose pertussis vaccine as Tdap or Tdap/IPV depending on other vaccine requirements

 

Why is Tdap recommended in each pregnancy?

This is on the basis of data showing that maternal antibodies to pertussis wane and so will not provide protection for newborn infants in subsequent pregnancies. In addition, available data do not suggest any increased incidence of adverse events in pregnant women who received Tdap vaccines in subsequent pregnancies.

 

What about post‐partum women?

Tdap should be offered in the week after delivery to those women who were not vaccinated during their pregnancy as it will provide protection to the mother from pertussis infection and so she will not be a source of infection for her baby.

 

Is Tdap recommended in pregnancy in other countries?

Tdap is recommended in pregnancy in many countries including the US, Canada, UK, Australia and New Zealand. The timing of the recommendation varies from country to country.

 

How effective is Tdap in pregnancy?

The introduction of the maternal pertussis immunisation programme in the UK in 2012 has been very effective in protecting infants with vaccine effectiveness estimated at 91%. Babies born to vaccinated mothers are 90% less likely to get disease than babies whose mothers were unvaccinated.

 

Is Tdap safe to give in pregnancy?

Yes. Evaluation of the pertussis vaccination in pregnancy programme in the US and England has demonstrated no safety concerns with no evidence of an increased risk of side effects. Tdap is an inactivated vaccine and so does not contain live organisms and cannot cause infection in the mother or the baby.

 

What are the side effects of Tdap?

  • Very common (>1 in 10): Local injection site reactions (pain, redness and swelling).
  • Common (> 1 in 100 to <1 in 10): Pyrexia, malaise, fatigue 
  • Rare Arthus reaction (see below)
  • Anaphylaxis develops in 1 in 1 million vaccinations

 

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.

 

Are there any reasons why Tdap should be deferred?

  • Tetanus containing vaccination should be deferred for 10 years if there has been an Arthus‐type reaction to a previous dose. (Arthus reactions are rarely reported after vaccination and can occur after tetanus or diphtheria toxoid containing vaccines. They typically develop 2‐8 hours after vaccination and involve swelling and erythema of most of the diameter of the upper arm from the shoulder to elbow. They are more common in adults and resolve without sequelae.
  • In the event of acute severe febrile illness defer until recovery.

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

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

 

If a woman has had confirmed or suspected whooping cough during pregnancy, should she still be offered the pertussis vaccine?

Yes, as not all women produce sufficiently high levels of antibodies following pertussis infection to ensure high levels can be passed across the placenta to the infant.

As high levels of antibodies are made following vaccination therefore offering vaccine from 16 weeks of pregnancy should ensure that optimal antibody levels can be passed to her baby.

 

Does a pregnant woman still need Tdap vaccine if she has recently received a tetanus containing vaccine for a tetanus prone wound?

 Yes, the Tdap vaccine is required from 16 weeks’ gestation because the tetanus containing vaccine used for tetanus prone wounds provides no protection against pertussis infection.

 

What should you do if you inadvertently administer Tdap vaccine to a pregnant woman before 16 weeks?

 Optimal neonatal pertussis antibody concentrations are elicited when the Tdap vaccine is given from 16 weeks in pregnancy. Therefore, the Tdap vaccine given in error before 16 weeks will not provide an optimal pertussis antibody concentration. The Tdap vaccine should be given again from 16 weeks of pregnancy and after an interval of 4 weeks from the Tdap given in error.

 

Can Tdap vaccine be given at the same time as flu vaccine or COVID-19 vaccine?

Tdap can be given at the same time as the flu vaccine: non live vaccines can be safely given together. However, do not delay giving flu vaccine so you can give both vaccines together.

Vaccinees should be informed there may be a slight increase in short term mild adverse events after co-administration with a seasonal influenza vaccine or COVID-19 vaccines. These include pain at the site of injection, fatigue, headache, and myalgia. 

However, do not delay giving flu vaccine so you can give both vaccines together. 

 

Can Tdap vaccine be given to a breastfeeding woman?

 Yes, Tdap vaccine can be given to a breast feeding woman. 

 

Can Tdap vaccine be given at the same time as Anti‐D?

 Yes, Tdap vaccine can be given at the same time as Anti‐D.

 

How can Tdap vaccine uptake be improved during pregnancy?

There is better uptake of vaccination when women have:

  • A recommendation from a trusted health professional
  • Awareness of vaccination
  • Access to accurate and timely information
  • Free vaccines

 

What can health care workers do to improve Tdap vaccine uptake?

  • Recommend the vaccine. A recommendation from a trusted healthcare professional has been shown to be strongly associated with uptake.
  • Be aware of current vaccine recommendations and know how to explain the benefits.
  • Use every contact to remind pregnant women about the importance of vaccines and when to receive Tdap (and flu) vaccine, even if your role doesn’t include administering vaccines.
  • Answer their questions and point to reputable sources of information like www.immunisation.ie 
  • Offer a chance to return to discuss vaccines again if they’re not ready to receive a vaccine at that appointment.
  • Take the e-learning module “Talking about Immunisation” available on www.HSEland.ie which focuses on communication with people who are hesitant about vaccines

 

Why is pertussis vaccine recommended for specific health care workers?

Pertussis is difficult to recognise and diagnose in adults – up to 30% of adults with a cough lasting more than two weeks may have pertussis.

There has been documented pertussis transmission from HCWs to patients and HCWs are exposed to pertussis much more frequently than the number of diagnosed cases suggests. 

Therefore, due to the risk of pertussis transmission to individuals vulnerable to severe pertussis infection, especially infants, healthcare staff working with infants or pregnant women should have Tdap vaccine.

Pertussis vaccine is recommended for HCWs to prevent nosocomial transmission and is recommended for HCWs in USA since 2005 and also in Australia, the UK and New Zealand.

Infants, pregnant women and the immunocompromised are the most vulnerable to pertussis infection. Tdap booster vaccination maybe considered every 10 years.

 

Which health care workers should be a priority for pertussis (Tdap) vaccination?

 A booster dose of Tdap is recommended for Health Care Workers who are in contact with infants, pregnant women and the immunocompromised. Boosters of Tdap every 10 years may be considered.

 

References

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This page was updated on 20 January 2025