(Date of issue: September 2016. Version: 3)
This factsheet has been written for members of the public by the UK Teratology Information Service (UKTIS). UKTIS is a not-for-profit organisation funded by Public Health England on behalf of UK Health Departments. UKTIS has been providing scientific information to health care providers since 1983 on the effects that medicines, recreational drugs and chemicals may have on the developing baby during pregnancy.
What is typhoid?
Typhoid is a potentially serious illness that is passed on through the consumption of contaminated food and drink and is linked to poor sanitation. Pregnant women may be more likely to catch typhoid infection and, if they catch it, are more likely to experience complications than non-pregnant individuals. Typhoid in pregnancy may also increase the risk of miscarriage. Typhoid is common in India, Southeast Asia, and the African continent. Vaccination is therefore usually recommended for travellers to these regions.
Should I be vaccinated against typhoid if I am pregnant?
Typhoid vaccines are given to reduce the risk of a person catching typhoid. UK guidelines recommend that pregnant women should ideally avoid travelling to areas where typhoid is common. Women who cannot avoid travelling to these areas should consider being vaccinated.
When deciding whether to have a typhoid vaccination during pregnancy it is important to weigh up how high your risk is of catching typhoid and the known risks of typhoid infection against the possible but unconfirmed risks to you or your baby of being vaccinated in pregnancy, some of which might depend on how many weeks pregnant you are. Your doctor is the best person to help you decide what is right for you and your baby.
Typhoid vaccines are available as an injection (Typherix®, Typhim Vi®) or in tablet form (Vivotif®). There is not enough scientific evidence about use of either the injected or tablet forms of the vaccine in pregnancy to be able to recommend one type over the other. However, the tablet form of the vaccine is a live vaccine. Because live vaccines are generally avoided in pregnancy your doctor may recommend the injected vaccine.
Because vaccination against typhoid might not provide complete protection against catching the illness it is important that people travelling to areas where the disease is common take strict precautions to avoid contact with potentially contaminated food and water. This includes drinking only bottled water, avoiding ice in drinks, avoiding eating raw fruits and vegetables, choosing hot foods, and washing your hands frequently in hot, soapy water.
Do I need to do anything if I had a typhoid vaccine but didn’t realise I was pregnant at the time?
There are currently no known risks to the mother or her unborn baby from being vaccinated against typhoid during pregnancy.
It is, however, always a good idea to let your doctor know that you are pregnant if you have been vaccinated or are taking any medicines. You and your doctor can then decide together whether you still need the medicines that you are on and that you are taking the lowest dose that works. Your doctor will also be able to assess whether you need any additional monitoring during your pregnancy.
Can being vaccinated against typhoid in pregnancy cause my baby to be born with birth defects?
A baby’s body and most internal organs are formed during the first 12 weeks of pregnancy. It is mainly during this time that some medicines are known to cause birth defects.
No large studies have investigated whether birth defects are more common in babies born to women vaccinated against typhoid in pregnancy. So far the only published scientific information available is from case reports of 16 babies born to women who received the tablet form of typhoid vaccine in the first trimester of pregnancy. Although none of these babies had birth defects, large, well-designed studies of the pregnancy outcomes of many more women vaccinated against typhoid in pregnancy are required.
Can being vaccinated against typhoid in pregnancy cause miscarriage?
One small study from the 1950s found that miscarriage rates were similar in a group of 107 women who received typhoid vaccine in pregnancy compared to a group of non-vaccinated women. However, much more research using modern analysis methods is required to confirm this finding.
Can being vaccinated against typhoid in pregnancy cause stillbirth, preterm birth, or my baby to be small at birth (low birth weight)?
A single, small study found that among 86 women who were vaccinated against typhoid in pregnancy none experienced a stillbirth and 85 of the babies were born at term (37 weeks of pregnancy or more). No studies have assessed whether low birth weight is more common in babies exposed in the womb to typhoid vaccine.
Although the findings on stillbirth and preterm birth do not raise any concerns, further large, high quality scientific studies that assess the rates of all of these pregnancy outcomes following typhoid vaccination in pregnancy are required to accurately answer these questions.
Can being vaccinated against typhoid in pregnancy cause learning and behavioural problems in the child?
A baby’s brain continues to develop right up until the end of pregnancy. It is therefore possible that taking certain medicines at any stage of pregnancy could have a lasting effect on a child’s learning or behaviour.
No studies have investigated learning and behaviour in children who were exposed in the womb to typhoid vaccines. Research into this subject is therefore required.
Will my baby need extra monitoring during pregnancy?
As part of their routine antenatal care most women will be offered scan and blood tests from around 11 weeks of pregnancy and a further scan at around 20 weeks to look for birth defects in the baby. Being vaccinated against typhoid in pregnancy is not expected to cause problems that would require extra monitoring of your baby.
Are there any risks to my baby if the father has been vaccinated against typhoid?
No studies have specifically investigated whether typhoid vaccine used by the father can harm the baby through effects on the sperm, however most experts agree that this is very unlikely. More research on the effects of medicine use in men around the time of conception is needed.
Who can I talk to if I have questions?
If you have any questions regarding the information in this leaflet please discuss them with your health care provider. They can access more detailed medical and scientific information from www.uktis.org.
Up to 1 out of every 5 pregnancies ends in a miscarriage, and 1 in 40 babies are born with a birth defect. These are referred to as the background population risks. They describe the chance of these events happening for any pregnancy before taking factors such as the mother’s health during pregnancy, her lifestyle, medicines she takes and the genetic make up of her and the baby’s father into account.
Medicines use in pregnancy
Most medicines used by the mother will cross the placenta and reach the baby. Sometimes this may have beneficial effects for the baby. There are, however, some medicines that can harm a baby’s normal development. How a medicine affects a baby may depend on the stage of pregnancy when the medicine is taken. If you are on regular medication you should discuss these effects with your doctor/health care team before becoming pregnant.
If a new medicine is suggested for you during pregnancy, please ensure the doctor or health care professional treating you is aware of your pregnancy.
When deciding whether or not to use a medicine in pregnancy you need to weigh up how the medicine might improve your and/or your unborn baby’s health against any possible problems that the drug may cause. Our bumps leaflets are written to provide you with a summary of what is known about use of a specific medicine in pregnancy so that you can decide together with your health care provider what is best for you and your baby.
Every pregnancy is unique. The decision to start, stop, continue or change a prescribed medicine before or during pregnancy should be made in consultation with your health care provider. It is very helpful if you can record all your medication taken in pregnancy in your hand held maternity records.