Vaccination against influenza during pregnancy

Influenza is a common illness caused by infection with the influenza virus. If you are pregnant and get influenza, you have a higher risk of becoming severely ill and developing complications that may affect both you and your unborn child. Severe influenza during pregnancy can increase the risk of preterm birth or low birth weight.

When you are vaccinated against influenza during pregnancy, you are better protected against influenza, and protective antibodies are also passed on to your unborn child. This means that your baby is better protected in the first months after birth.

Vaccination also reduces the risk that you, as a mother, pass influenza on to your baby after birth.

In this way, the vaccine helps protect both you and your newborn baby against severe illness and complications due to influenza.

Pregnant women get influenza as often as other women of the same age, but the illness can be more severe, especially from the second trimester onwards. There are several reasons for this: the immune system changes temporarily during pregnancy, which may make pregnant women more susceptible to infections; the heart and lungs work harder; and the growing baby reduces lung capacity. This increases the risk of complications and therefore also the risk of hospitalisation due to influenza.

The risk of complications from influenza increases as pregnancy progresses. Vaccination is therefore recommended during the autumn and winter season for all pregnant women in their second and third trimester. Vaccination is offered between 1 October and 20 December.

Pregnant women with additional risk factors for severe influenza are recommended vaccination from the first trimester. If you are unsure whether vaccination is recommended for you, you can speak to your GP or midwife. You can also read more about other risk factors here.

If you are pregnant, you can book an appointment for influenza vaccination from late September until 20 December at www.vacciner.dk. Vaccination is given at a regional vaccination site.

When you are vaccinated against influenza, your body produces antibodies against the influenza virus. This means your immune system learns to recognise the virus and can better fight the infection if you are exposed later. Protective antibodies are also passed on to the unborn child through the placenta, helping protect the baby in the first months after birth.

The effectiveness of influenza vaccination depends on how well the vaccine matches the circulating virus strains in a given season. Vaccination reduces the risk of influenza in pregnant women by around 50% to 70%, although effectiveness may be lower in some seasons. Vaccination also reduces the risk of severe illness if you do become infected, even if you have been vaccinated.

All vaccines can cause side effects, including the influenza vaccine.

The most common side effects are soreness at the injection site, headache and fatigue. Some people also experience muscle and joint pain and a general feeling of being unwell. Side effects are usually mild and temporary.

Serious side effects, such as a severe allergic reaction, are very rare. If you have previously had a severe allergic reaction following a vaccine or another injection, you should speak to your GP before being vaccinated.

Influenza vaccination during pregnancy is not associated with an increased risk of harm to the fetus or the newborn baby. This means that the vaccine is safe for your baby.

Yes, there is extensive experience with vaccinating pregnant women against influenza. In Denmark, pregnant women have been offered influenza vaccination since 2010. Influenza vaccination is also offered to during pregnancy in a number of other countries, including Sweden, Norway, Finland, France, Germany and Canada.

The Danish Health Authority recommends that pregnant women be vaccinated against influenza with each new pregnancy if they are in their second or third trimester during the autumn and winter period. Vaccination is offered from 1 October to 20 December.

You are not protected against influenza even if you have had the disease before or have been vaccinated previously. This is because there are several types of influenza, and the influenza virus can change from year to year. In addition, the effect of the vaccination wears off after about six months.

The following vaccinations are offered to pregnant women:

• Whooping cough vaccination at week 25 with your GP, offered uear-round.

• RSV vaccination at week 32 with your GP from May to January

• Influenza vaccination in the second and third trimesters from 1 October to 20 December at a regional vaccination site as part of the seasonal vaccination programme.

If you have a chronic disease or condition that puts you at increased risk of severe COVID-19, you are also offered for vaccination against COVID-19 from 1 October to 20 December, regardless of whether you are pregnant. You can read more here.

Influenza vaccination can be given on the same day as RSV and whooping cough vaccination or at any interval.

It is recommended that at least two weeks pass between whooping cough and RSV vaccination.