Can You Get the RSV Vaccine During Pregnancy? Benefits, Risks and Timing Explained

Respiratory syncytial virus (RSV) is a common respiratory virus that spreads through droplets and contact with contaminated surfaces. In adults, it often causes cold-like symptoms. In newborns, however, it can cause bronchiolitis—an infection of the small airways—or pneumonia, sometimes requiring hospital treatment. Receiving an approved RSV vaccine during pregnancy can give your baby early protection. However, being eligible for vaccination does not mean that every pregnant woman must receive it.

Which RSV Vaccine Is Suitable During Pregnancy?

Not all RSV vaccines are suitable for pregnant women. Abrysvo is approved for use during pregnancy; Arexvy and mResvia are not.

In the United States, the recommended schedule is a single dose between 32 weeks and 36 weeks and 6 days of pregnancy. Your vaccination plan should follow local guidance and your doctor’s assessment.

Hong Kong’s interim consensus, published in January 2025, did not recommend universal RSV vaccination for all pregnant women. Instead, pregnant women can make an informed individual decision after consulting their doctor. This does not mean the vaccine is unsuitable during pregnancy; rather, a universal vaccination policy requires further safety data.

The Benefits: Reducing Your Baby’s Risk of Severe Illness

The vaccine stimulates your immune system to produce antibodies, which pass through the placenta to your baby. Its main purpose is not to prevent cold-like symptoms in the mother, but to protect the baby during the particularly vulnerable first six months of life.

Clinical trials showed that vaccination during pregnancy reduced the relative risk of severe RSV illness in babies by approximately 82% during the first three months after birth and 69% during the first six months. It also reduced the risk of RSV-related hospitalisation by approximately 57% during the first six months.

These figures describe relative reductions in risk. They do not mean that the same percentage of babies will be completely protected from infection. Nevertheless, vaccination can meaningfully reduce the likelihood of severe illness and hospitalisation.

The Drawbacks and Limitations: Side Effects and Risks Under Investigation

Common side effects include pain at the injection site, headache, muscle pain and nausea. These are usually short-lived.

Anyone who has had a severe allergic reaction to a vaccine ingredient should not receive it. If you have a moderate or severe acute illness, vaccination should generally be postponed until you recover.

In an early clinical trial, premature births were slightly more frequent in the vaccine group than in the placebo group. However, the difference was not statistically significant, so the findings did not establish that the vaccine caused premature birth.

Monitoring after the vaccine’s introduction has not shown an increased risk of premature birth. Possible links with high blood pressure disorders during pregnancy, including pre-eclampsia, remain under investigation. A causal relationship has not been established. It would therefore be misleading to describe the vaccine as completely risk-free.

Protection also gradually decreases over time. The vaccine does not prevent every respiratory infection and cannot replace everyday hygiene measures.

Practical Advice for Expectant Mothers

At your antenatal appointment, consider asking: “Is vaccination appropriate for my stage of pregnancy and due date? Could my medical history affect the decision?”

Tell your obstetrician if you have a history of premature birth, high blood pressure during pregnancy or severe allergic reactions. Confirm the vaccine brand and cost before making an appointment.

It takes approximately two weeks for antibodies to develop and pass to your baby. If you are close to delivery, have missed the vaccination window or cannot receive the vaccine, ask your paediatrician whether a long-acting RSV monoclonal antibody would be suitable for your baby after birth. This is not a vaccine; it provides protective antibodies directly. Most babies do not need both approaches, and the choice depends on individual circumstances and local availability.

RSV can circulate throughout the year in Hong Kong, so vaccination months recommended in the United States should not be applied automatically. Whether or not you are vaccinated, family members should wash their hands regularly and avoid kissing or having close contact with the baby when unwell.

For eligible pregnant women, the RSV vaccine is a worthwhile option to consider for protecting their baby. The key is to weigh the benefits and risks with your doctor, taking account of your stage of pregnancy, health and local recommendations—rather than accepting vaccination without discussion or dismissing it solely because of concerns about side effects.

This article provides general health information and does not replace an individual medical assessment.