RSV (respiratory syncytial virus) vaccine - what you need to know

The respiratory syncytial virus, or RSV, vaccine is an injection that helps prevent serious illness caused by RSV. RSV commonly affects the airways and lungs. Although many infections are mild, some people have a higher risk of pneumonia, breathing problems, or hospital treatment.

RSV vaccines are mainly offered to certain older adults and during specific weeks of pregnancy. Vaccination during pregnancy allows protective antibodies to pass through the placenta to the baby. These antibodies help protect the baby during the first months after birth.

Several RSV vaccines are available. They are not interchangeable for every use. In particular, only the RSV vaccine specifically approved for pregnancy should be used during pregnancy.

The vaccine cannot cause RSV infection. Some vaccines contain a protein from the virus, while another uses messenger RNA, or mRNA, to teach the immune system how to recognize that protein. None contains live RSV.

The vaccine is given to reduce your chance of becoming seriously ill with RSV. It does not guarantee that you will avoid infection, but it can lower the risk of severe lung disease and hospital treatment.

For older adults, the benefit is greatest when age, medical conditions, living arrangements, or immune problems increase the risk of serious RSV illness.

During pregnancy, vaccination is intended mainly to protect the baby. The timing matters because your body needs time to make antibodies and pass them to the baby before birth.

RSV vaccination does not treat an infection you already have. If you currently have breathing symptoms or feel unwell, you may need an assessment for the cause rather than vaccination alone.

In the United States, RSV vaccination is routinely recommended for adults aged 75 and older. It is also recommended for adults aged 50 to 74 who have an increased risk of severe RSV illness. Risk factors can include chronic heart or lung disease, a weakened immune system, severe obesity, certain other long-term conditions, or living in a nursing home.

During pregnancy, the Abrysvo RSV vaccine may be offered from 32 weeks through 36 weeks and 6 days of pregnancy. In most of the continental United States, it is given during the seasonal window from September through January. Timing can differ in places where RSV seasons occur at other times.

You should not receive a vaccine if you previously had a severe allergic reaction to that vaccine or one of its ingredients. Tell the vaccination team about all serious allergies before the injection.

Vaccination may be delayed if you have a moderate or severe short-term illness, especially with fever. A minor illness, such as a mild cold, does not always require delay.

Important limits include:

• Arexvy and mResvia are not approved for vaccination during pregnancy
• Abrysvo should not be given outside its approved pregnancy window to protect a baby
• An additional RSV dose is not routinely given every year under current US guidance
• Previous RSV infection does not provide reliable long-term protection

Your healthcare team should consider your age, pregnancy stage, health conditions, previous RSV vaccination, and personal preferences before offering the vaccine.

Follow the instructions from the facility giving your vaccine. Its own instructions take priority over general information in this article.

You normally do not need to fast. Eat and drink as usual unless the facility tells you otherwise. Wearing a loose shirt or short sleeves can make your upper arm easier to reach.

Before the appointment, tell the vaccination team if you:

• Have had a serious reaction to any vaccine
• Are pregnant or may be pregnant
• Have received an RSV vaccine before
• Are currently unwell or have a fever
• Have a bleeding disorder or take a blood thinner like warfarin or apixaban
• Have fainted during previous injections

Blood thinners do not automatically prevent vaccination, but the team may use extra pressure on the injection site to reduce bruising. Do not stop prescribed medicine unless the clinician responsible for it tells you to.

You will usually sit in a chair. The vaccination professional checks the vaccine, your eligibility, allergies, and consent.

The skin over your upper arm may be cleaned. A fine needle is then used to inject the vaccine into the deltoid muscle, the large muscle at the top of the arm. The injection itself takes only a few seconds.

No anaesthetic or sedation is needed. You may be asked to remain seated for a short observation period afterward, often about 15 minutes. Longer observation may be appropriate if you have certain allergy histories.

The vaccination should be recorded in your medical or immunization record. Keep any card or electronic confirmation you receive.

Pain: Your arm may feel sore, tender, or heavy. A cool compress and gentle arm movement may help. Ask your healthcare team which pain medicine is suitable if you need it.

Eating: You can eat and drink normally. Fluids may help if you feel tired or develop a mild headache.

Activity: Most people can continue normal daily activities. Consider lighter activity if you have fatigue, muscle aches, fever, or dizziness. Avoid pressing or rubbing the injection site aggressively.

Driving: The vaccine itself does not create a routine driving restriction. Do not drive if you feel faint, dizzy, weak, or otherwise unable to control a vehicle safely.

Work: Many people return to work immediately or the next day. If your job involves heavy lifting, a sore arm may make some tasks uncomfortable. Short-lived tiredness or aches may also affect physically demanding work.

Most expected reactions begin within a day or two and improve over the next few days.

Common reactions include pain, redness, or swelling where the injection was given. You may also have fatigue, headache, muscle or joint aches, fever, nausea, or chills. These effects are signs of an immune response, although having no reaction does not mean the vaccine failed.

Fainting can occur around injections. Sitting or lying down prevents injury if you become light-headed.

A severe allergic reaction, called anaphylaxis, is uncommon but requires emergency treatment. Vaccination sites keep medicines and equipment available for this reason.

Safety monitoring has identified a possible increased risk of Guillain-Barré syndrome after some RSV vaccines in older adults. This is a rare condition in which the immune system affects the nerves, causing weakness, tingling, or difficulty walking. The overall decision should weigh this possible risk against your personal risk from RSV.

Trials of Abrysvo during pregnancy found a numerical difference in premature births between study groups, but it was not clear that the vaccine caused this. Its approved 32-through-36-week timing is intended to limit potential risk while allowing antibodies to reach the baby.

There is no routine blood test to confirm that the RSV vaccine worked. Your immune system develops protection after vaccination, but the exact level of protection cannot be measured during a standard appointment.

Keep a record of the product and date. RSV vaccination is currently given as a single dose to eligible older adults rather than as an annual vaccine. Recommendations may change as researchers learn how long protection lasts.

If you received the vaccine during pregnancy, make sure the baby’s healthcare team knows. Most babies do not need both maternal vaccination and an infant RSV antibody, but an antibody may be advised in some circumstances.

Routine follow-up is not usually needed if you feel well. Discuss future RSV prevention during regular health or pregnancy appointments.

You can choose not to receive the vaccine. Measures such as handwashing, improving ventilation, avoiding close contact with people who are ill, and staying home when sick may reduce exposure. These steps do not provide the same immune protection as vaccination.

For an infant, a long-acting antibody injection such as nirsevimab or clesrovimab may be an alternative to vaccination during pregnancy. It gives the baby ready-made antibodies rather than relying on antibodies passed through the placenta. The timing, availability, and eligibility rules differ. Most babies need maternal vaccination or an infant antibody, not both.

Older adults do not have an equivalent long-acting antibody option for routine RSV prevention. Choosing no vaccination avoids vaccine reactions but leaves more of the RSV risk unchanged.

If the timing is unsuitable because you are acutely unwell, postponing the appointment is usually preferable to abandoning vaccination altogether. During pregnancy, however, delaying beyond the approved window may mean infant antibody protection is the more suitable option.

Contact your healthcare team routinely if expected arm pain, fever, or fatigue is worsening or has not started to improve after a few days. Also call if you develop a spreading rash or substantial swelling around the injection site.

Seek urgent medical advice for new tingling, increasing weakness, trouble walking, or facial weakness, particularly during the weeks after vaccination.

If you are pregnant, urgently contact your maternity team for contractions, vaginal bleeding, leaking fluid, reduced fetal movement, or other pregnancy concerns. These symptoms need assessment whether or not they are related to vaccination.

Call emergency services for difficulty breathing, swelling of the face or throat, widespread hives with weakness, collapse, or other signs of a severe allergic reaction.

Will I be asleep?

No. This is a quick injection into your upper arm. It does not require sedation or anaesthesia.

Can I drive home?

Usually, yes. Wait until any observation period is complete, and do not drive if you feel faint, dizzy, or unwell.

How painful is it?

You may feel a brief sting. Arm soreness afterward is common and is usually manageable with gentle movement and a cool compress.

When will I know whether it worked?

There is no immediate result and no routine test. Your immune system builds protection after vaccination. The vaccine lowers risk but cannot prevent every RSV infection.

Can I get it with other vaccines?

RSV vaccines can often be given at the same appointment as other vaccines. Receiving several vaccines together may increase short-term reactions such as arm pain or tiredness. Ask which timing best fits your needs.

Do I need an RSV vaccine every year?

Not under current US guidance. Eligible older adults generally receive one dose rather than yearly vaccination. Future recommendations may change as evidence about lasting protection develops.