Most flu jab side effects are mild and expected, a sign your immune system is responding, not a sign something has gone wrong. Common reactions include a sore arm, a slightly raised temperature and general aching, usually settling within a day or two.
In this article, we’ll cover the most common flu jab side effects, how long they typically last, and the rare signs that mean you should seek medical advice.
What Are the Most Common Flu Jab Side Effects?
The most common flu jab side effects are mild. You may notice some soreness around the injection site or feel a little under the weather for a day or so. According to NHS guidance, typical flu jab side effects include:
- Pain or soreness where the injection was given
- A slightly raised temperature
- An aching body
- Feeling more tired than usual
How Long Do Flu Jab Side Effects Last?
Flu jab side effects usually settle within one to two days. If soreness, fever or aching continues for longer or starts getting worse rather than better, speak to a pharmacist rather than assuming it will clear up by itself.
Is It Normal to Feel Unwell After a Flu Jab?
Yes, feeling mildly unwell after a flu jab can be normal and does not mean you have the flu. The injected flu vaccine used in the UK does not contain live flu virus, so it cannot give you flu. Any mild symptoms are part of your immune response as your body builds protection.
What’s Not a Normal Flu Vaccine Reaction?
Serious flu vaccine reactions are very rare, but it is useful to know what to look out for. A severe allergic reaction, known as anaphylaxis, can cause:
- Difficulty breathing or wheezing
- Swelling of the face, lips or throat
- A fast heartbeat or feeling faint
- A widespread rash or hives
Anaphylaxis usually develops within minutes of vaccination, which is why you may be asked to wait briefly after your jab. Staff who give the vaccine are trained to treat it immediately, according to NHS guidance. If you develop any of these symptoms after leaving, call 999 or go to A&E straight away. You can also report suspected side effects through the MHRA Yellow Card scheme.
Get Your Flu Jab at Periville Pharmacy
Knowing what to expect after a flu jab can make it easier to tell the difference between a normal reaction and something that needs attention. For most people, side effects are limited to things such as a sore arm or feeling slightly tired for a short time.
Book your flu jab with Periville Pharmacy, where our trained team can explain what to expect and answer any concerns before your vaccination. Choose an appointment at either of our two branches. We will be happy to answer any questions and make sure you feel comfortable before your vaccination.
Frequently Asked Questions
What are the most common flu jab side effects?
Common flu jab side effects include a sore arm, a slightly raised temperature and general aching, usually appearing within a day of vaccination.
How long do flu jab side effects last?
Most flu jab side effects last one to two days and settle without any treatment.
Can the flu jab give me the flu?
No. The injected flu vaccine used in the UK doesn’t contain live flu virus, so it cannot give you flu, though you may feel mildly unwell as your immune system responds.
What does a serious flu vaccine reaction look like?
A serious reaction, known as anaphylaxis, is very rare and can cause difficulty breathing, swelling of the face or throat, or a fast heartbeat, usually within minutes of vaccination. Staff are trained to treat this immediately.
Should I be worried about flu jab side effects in the UK?
No. The vast majority of flu jab side effects reported across the UK are mild and short-lived. Serious reactions are closely monitored and remain very rare.
What should I do if my flu jab side effects don’t go away?
If soreness, fever or aching lasts longer than a couple of days or gets worse, speak to a pharmacist or GP rather than waiting it out.