Respiratory syncytial virus (RSV) vaccination

What is the RSV vaccine?

RSV is a common virus which causes lung infections (respiratory tract disease). An RSV infection can happen at any age. In older children and younger adults, it usually causes a mild illness. However, in young children and older adults, it can cause serious infections.

RSV causes bronchiolitis, a common illness in babies and children under 2. RSV season, or bronchiolitis season, is usually over winter, and sees many young children ending up in hospital. In very severe cases, it can cause death. Around 20 to 30 children a year die from RSV infections in the UK.

RSV infection also causes more severe lung infections in older people, and often causes them to be admitted to hospital.

The RSV vaccine used in the UK is Abrysvo. This is a subunit vaccine, which means it contains purified parts of the RSV virus. The vaccine trains the immune system to recognise these parts of the virus and produce antibodies to protect against it.

The vaccine does not contain any live RSV, and it cannot cause RSV infections.

Who should have the RSV vaccine?

From 1st September 2024, the UK RSV vaccination programme offers vaccines to:

• Pregnant women - at any time between 28 weeks and birth.

• All adults aged 75-79 years.

  • This will change to be just adults turning 75 years, but initially the programme includes a 'catch-up' for people up to 79.

For both groups, this is a one-off dose of the RSV vaccine.

Having the RSV vaccine whilst pregnant protects your baby against infection for their first few months after being born when they are most vulnerable. Babies get most of their protection against infections from their mother. This stays in the baby's system for months, until their own immune system starts to work properly. Antibodies are also passed to your baby through breastfeeding.

Can children have the RSV vaccine?

If your child has a high risk of severe RSV disease they can have a different form of immunisation than is given to adults.

In the UK, highest-risk children include:

• Premature babies and infants with conditions such as heart or lung disease.

• Infants with major lung diseases, usually those who need long-term oxygen or assisted breathing (ventilation).

• Infants who have inherited (congenital) heart disease and other major medical problems.

• Infants with a severely weakened immune system, due to a condition called severe combined immunodeficiency syndrome (SCID).

High risk children are given injections of a purified antibody against RSV, called palivizumab (Synagis). This gives protection against RSV for around one month. Your child will usually be given repeated monthly doses throughout the RSV season, to maintain protection.

There is also another type of RSV immunisation, called nirsevimab (Beyfortus). Nirsevimab works in a similar way but can provide protection against RSV for several months.

Nirsevimab is not currently used in the UK, because vaccinating pregnant women was felt to be a better alternative. It is, however, used in other countries, such as the USA, where it is part of the CDC recommendations for immunisation of infants.

Palivizumab and nirsevimab are technically not vaccines. They give your baby antibodies against RSV, which are eventually broken down by their body after several months.

Researchers have been trying for decades to make an RSV vaccine that can be given directly to babies, infants, and children. It has been very difficult to make one that works well enough, although new vaccines are in development, and might be available in future.

Who should not have the RSV vaccine?

If you have previously had a serious allergic reaction (anaphylaxis) to the RSV vaccine, or one of its ingredients, you should not have it.

This is very rare, so almost everyone in the eligible groups can have the RSV vaccine safely.

How effective is the RSV vaccine?

The RSV vaccine is very effective at preventing babies and older people from getting seriously ill with RSV.

For pregnant women and their babies

If you are pregnant the RSV vaccine gives protection to your baby from birth up to, at least, 6 months of age.

The RSV vaccine is probably more effective if given at least 2 weeks before you give birth. This allows time for you to produce your own antibodies and share them with your baby, but it can be given at any time up to birth.

In the UK, it's recommended to have the RSV vaccine at 28 weeks of pregnancy, if possible.

Clinical trials show that the RSV vaccine for pregnant women:

• Prevents around 80% of severe RSV infections in babies up to 3 months of age.

• Prevents around 70% of severe RSV infections up to 6 months of age.

• Protects against less severe RSV infections, preventing around 50-60% of all RSV infections, up to 6 months of age.

For older adults

In older adults, research trials show that the RSV vaccine is between 65% and 90% effective at preventing RSV infections.

Is the RSV vaccine available in the UK?

The RSV vaccine has been available in the UK on the NHS for eligible groups - see 'Who should have the RSV vaccine', above - since 1st September 2024.

Both Abrysvo and another RSV vaccine, Arexvy, are licensed for use in the UK, and may be available privately as well.

Are there any side-effects from the RSV vaccine?

The RSV vaccine is safe. Serious side-effects are very rare.

Very common side-effects - affecting more than 1 in 10 people - include:

• Pain at the injection site.

• Feeling tired.

• Muscle aches.

• A headache.

• Joint pains.

Common side-effects - affecting between 1 in 100, and 1 in 10 people - include:

• Having a high temperature (fever).

• Chills or shivering.

These side effects are usually mild and disappear within a few days.

Rare side effects

Some serious side-effects are possible - but are rare and it has not been proven that these are definitely caused by RSV vaccination.

• In older adults, a very small number of cases of Guillain-Barré syndrome, a serious neurological illness, have been reported after RSV vaccination.

  • This has been reported in around 5 per million people who had Abrysvo.

  • It's not yet clear if this is actually due to the vaccine, or something else.

  • Even if it is linked, the benefits of a RSV vaccine in older adults still far outweigh this very small risk.

• Abrysvo®, the RSV vaccine used in the UK, is safe in pregnancy.

  • In pregnant women, there were some concerns during the research trials that RSV vaccination might slightly increase the risk of premature (preterm) birth, but we now have evidence that this is not the case.

  • In one research trial, a different RSV vaccine (not currently in use) was linked with an increased risk of preterm birth.

  • This led the US Food and Drug Administration (FDA) to approve Abrysvo, the RSV vaccine that is currently available for pregnancy, from 32 weeks of pregnancy only, as a precaution.

  • However, detailed analysis of the research data, and more recent studies of pregnant women who have had Abrysvo, show that there is no evidence to show that it is linked with preterm birth.

  • The UK's Medicines and Healthcare products Regulatory Agency (MHRA) have licensed Abrysvo® for use from 28 weeks of pregnancy.

  • The EU's European Medicines Agency (EMA) have licensed Abrysvo® for use from 24 weeks of pregnancy.