The flu season rarely starts before mid-November in the Northern Hemisphere, and commonly runs to the end of May the following year ⁽¹⁾. So, when is the best time to get your flu vaccine?

When should you get your flu vaccine?

The best time of the year to have a flu vaccination is in the autumn, from the beginning of October to early November ⁽²⁾. Getting vaccinated later, however, can still be beneficial – even into January or later ⁽³⁾.

After vaccination, it takes your body 10 to 14 days to develop an immune response that protects you from the flu ⁽⁴⁾. The protection provided by the vaccine is then expected to last for at least one flu season, but it does wane with time ⁽⁴⁾. That is why new flu vaccines are produced each year and why people are advised to get vaccinated against the flu every year too ⁽⁵⁾.

What other things should I consider?

If you’re ill and have a fever, consider delaying your flu vaccination until you’ve recovered ⁽⁶⁾. There’s no need to delay, however, if you have a minor illness with no fever, such as a cold. It’s also fine to have the flu vaccine while you’re taking antibiotics ⁽⁶⁾.

If you have cancer and are having or have had cancer treatment that’s likely to affect your immune system, protecting yourself from flu is very important7. The flu vaccine is safe for most people who have cancer ⁽⁷⁾. Having the vaccine at least two weeks before you start the treatment would be best ⁽⁷⁾, if that’s possible. If you’re unsure, talk to your doctor or nurse.

When is getting the flu vaccine important?

If you’re 65 or over, you’re at higher risk of complications if you catch the flu ⁽⁸⁾. That makes you more vulnerable than others. Get vaccinated to protect yourself from the flu is important – particularly if you also have underlying health conditions.

In fact, experts recommend the flu vaccine for anyone over six months old who is more likely to develop severe flu ⁽⁹⁾ – including older adults and people with a chronic medical condition, physical handicap, BMI greater than 40 or weakened immune system ^{(10, 11)}. Examples of chronic conditions include chronic respiratory, heart, kidney or liver diseases, Parkinson's disease, motor neurone disease, multiple sclerosis (MS) and diabetes ^{(10, 11)}.

When should you speak to your doctor?

Speak to your doctor about getting the flu vaccine if you have an egg allergy; you may be at increased risk of a reaction to the injected flu vaccines made using eggs ⁽¹²⁾. In recent years, however, egg-free versions have become available. Your doctor may be able to find a suitable flu vaccine with a low egg content or decide to refer you to a specialist.

Some people who have had Guillain-Barré Syndrome (GBS) should not get the flu vaccine ⁽¹³⁾. Discuss your GBS history with your doctor, and they will advise you.

Finally, always speak to your doctor if you’ve had a severe allergic reaction to it in the past. People with severe, life-threatening allergies to the flu vaccine or any ingredient in the vaccine, such as gelatine or antibiotics, can’t get the shot ⁽¹³⁾.

Sources
(1) https://ecdc.europa.eu/en/seasonal-influenza/prevention-and-control/vaccines/timing
(2) https://www.nhs.uk/Livewell/winterhealth/Pages/Fluandthefluvaccine.aspx
(3) https://www.cdc.gov/flu/consumer/vaccinations.htm
(4) https://ecdc.europa.eu/en/seasonal-influenza/prevention-and-control/vaccines/timing
(5) https://www.nhs.uk/Conditions/vaccinations/Pages/flu-influenza-vaccine.aspx
(6) https://www.nhs.uk/Conditions/vaccinations/Pages/who-shouldnt-have-flu-vaccine.aspx
(7) https://community.macmillan.org.uk/blogs/b/new_information_available/archive/2017/10/30/the-flu-vaccine-and-cancer-treatment
(8) https://ecdc.europa.eu/sites/portal/files/media/en/healthtopics/seasonal_influenza/communication_toolkit/Documents/poster ECDC_RG.pdf
(9) https://ecdc.europa.eu/en/seasonal-influenza/prevention-and-control/vaccines/vaccination-strategies
(10) https://ecdc.europa.eu/en/seasonal-influenza/prevention-and-control/vaccines/risk-groups
(11) https://www.nhs.uk/Conditions/vaccinations/Pages/who-should-have-flu-vaccine.aspx
(12) https://www.nhs.uk/Conditions/vaccinations/Pages/who-shouldnt-have-flu-vaccine.aspx
(13) https://www.cdc.gov/flu/protect/whoshouldvax.htm