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Day 214 of 280 · 30 weeks + 4 days

The RSV decision

Last reviewed · 3 min read · 4 sources · Plain-text version

Thirty weeks and four days. An RSV vaccine in pregnancy can protect your baby through their first months. Today you find out which one, when, and whether it fits you.

Size this week
about the size of a cabbage
Length this week
around 39.9 cm from head to heel
A woman with a full bump in a rust-coloured cardigan talking with a midwife in a bright clinic room, both seated, the midwife listening with a pen and paper folder on her lap.

Thirty weeks and four days. There's an RSV vaccine you can have in pregnancy, and the protection it gives is for your baby. The timing depends on where you live and what time of year your baby is due. Today you sort out which rules apply to you.

Your baby

A single green cabbage on a plain pale wooden table, soft window light.

Around 39.9cm from head to heel, about the size of a cabbage (NHS). The RSV vaccine you get now is for them: the NHS says it lowers your baby's risk of bronchiolitis (NHS), and the AAP says the maternal vaccine protects the baby for 6 months (AAP).

Your body

The UK and US do this differently, and it's worth knowing which you're following. In the UK, the RSV vaccine is usually offered around week 28 and can be given until labour starts (NHS).

In the US, the CDC's guidance is one dose of Abrysvo between 32 weeks 0 days and 36 weeks 6 days, given seasonally from September through January in most of the continental US (CDC). Abrysvo is the only RSV vaccine used in pregnancy; Arexvy and mResvia should not be given (CDC). If you had a maternal RSV vaccine in a previous pregnancy, you shouldn't get another dose; your baby gets nirsevimab instead (CDC). Alaska, Puerto Rico and other places with different RSV seasons follow local timing (CDC).

Try today

  1. The RSV decision

    Time: 10 minutes

    1. Write down your due date and the month it falls in. In the US, the season for the pregnancy vaccine is September through January (CDC).

    2. Note whether you had an RSV vaccine in a previous pregnancy.

    3. At your next visit, ask three things: which product, which week, and whether the season timing applies to you (CDC).

    4. Write the answer on your vaccine checklist, with the date if it's booked.

    Make it work:

    If the vaccine doesn't fit your timing, ask about the baby's own protection instead. The AAP notes that babies born less than 14 days after the maternal dose need nirsevimab (Beyfortus) (AAP).

Watch for

  • Normal

    a sore arm or a tired day after a vaccine.

    Call your provider

    for a fever of 100.4°F (38°C) or higher, which the CDC lists as an urgent warning sign (CDC).

  • Normal

    your baby's own rhythm of busy and quiet times.

    Call your provider

    if their movement stops or slows; the CDC says there's no set number that counts as normal, and a change is what matters (CDC).

  • Normal

    not being sure whether something is worth a call.

    Call your provider

    if you feel like something just isn't right, even if it isn't on any list; tell them you're pregnant, and trust your instincts (CDC).

For you

Vaccine decisions can come with a lot of noise. The AAP's version is short: RSV is one of four vaccines it recommends in pregnancy, and the only one given during just one pregnancy (AAP). You don't have to settle every other question online. Bring the three questions to someone who knows your dates and your history, and decide with them.

If you're the partner: put the vaccine window in your calendar too, with a reminder a week before. A date both of you are holding is much harder to miss.

Sources

This guide is general education that summarizes published research and guidance from groups like the American Academy of Pediatrics, the CDC, and the WHO. It isn’t medical advice, and every child develops on their own timeline. Your pediatrician knows your child; if something feels wrong, call them. In an emergency, call 911.

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