When is it too late to get the RSV vaccine this season?

The RSV vaccine for adults 60+ is available year-round, but its value depends on timing. Like the flu shot, the RSV vaccine needs time after injection for your immune system to build a protective response. Getting vaccinated mid-season is still worthwhile in most cases — but understanding the timeline helps you make the most of it.

How long does it take the RSV vaccine to work?

After injection, your immune system begins producing RSV-specific antibodies within days, but the response takes time to build to fully protective levels. Based on data from the clinical trials:

• Partial protection: begins within about 7–14 days
• Full protection: approximately 2–4 weeks after vaccination

This means if you get vaccinated today, you should expect meaningful protection within 2 weeks and near-full protection by 4 weeks.

When is the ideal time to get vaccinated?

The ideal window is late summer to early fall — August through October — so that protection is fully established before RSV season peaks. RSV season in the US runs roughly October through March nationally, with the Southeast and South Central regions starting earlier (August–September in some years).

Vaccination in September or October gives you full protection well before the typical November–January peak in most of the country.

Is it still worth getting vaccinated once RSV season has started?

Yes — for most people. RSV season spans roughly 5–6 months. Getting vaccinated in November, December, or even January means you'll still have several months of RSV circulating during which you benefit from protection. The vaccine doesn't stop working mid-season — immunity established by January still covers February and March, which can be significant RSV months.

The exception is if RSV activity in your area has already peaked and is clearly declining. If you're in mid-March and your state's activity has dropped to Low, the remaining season risk may not justify the visit — but that's a judgment call worth making with your doctor.

What if you've already had RSV this season?

Natural RSV infection produces some immunity, but it's incomplete and wanes over time — you can get RSV again the following season (or even later in the same season, though that's rare for otherwise healthy adults). If you had RSV illness earlier this season, talk with your doctor about whether vaccination is still beneficial for protection in future seasons. In most cases, the vaccine is still worthwhile — the immune response from vaccination is generally more robust and more consistent than from natural infection.

Does the RSV vaccine need to be given every year?

Unlike the flu vaccine, the RSV vaccine for adults 60+ is currently approved as a single dose with no established annual revaccination recommendation. The protection is expected to last at least 1–2 seasons based on trial follow-up data, though longer-term durability data is still being collected. The CDC will update guidance as that data matures.

If you've never received an RSV vaccine, any time you're within the eligible window (60+) is a reasonable time to get it — including mid-season.

Can I get the RSV vaccine and flu shot at the same appointment?

Yes. The RSV vaccine can be co-administered with flu and COVID vaccines at the same visit. If you haven't had your flu shot yet this season and are getting an RSV vaccine, doing them together is efficient and safe. Some people prefer to space vaccines by a few days to make side effects easier to attribute — that's fine too, but not medically necessary.

Summary: a simple decision rule

If RSV is actively circulating in your state (activity at Moderate or higher) and you haven't been vaccinated: get the vaccine now. The 2-week lag to full protection is a small cost compared to the months of remaining season. If activity has already declined to Low or None and you're healthy without high-risk conditions, you may choose to wait for next fall — though getting vaccinated now still covers future seasons.

Not medical advice. Timing decisions depend on your individual health situation. Always discuss vaccination with your doctor or pharmacist.