The NHS flu vaccination programme has officially begun, and all individuals who are eligible can now schedule their free jabs. For most people, receiving the flu vaccine is considered safe and beneficial, but there are two specific groups who should proceed with caution—or avoid vaccination altogether under certain circumstances.

Delaying vaccination if you are unwell

Official guidance advises that anyone who is feeling unwell or has a high temperature should postpone getting the vaccine until they recover. Because the vaccine temporarily stimulates the immune system, if your body is already battling an infection, it may not mount an effective response to the vaccine. Additionally, vaccinating while moderately or severely ill can make it difficult to distinguish between vaccine side effects and symptoms of the illness itself.

The NHS flu vaccination programme for this season continues through 31 March 2026, and while getting vaccinated earlier helps ensure protection during the peak of flu season, it may be wiser to wait until you feel better if you are currently unwell (NHS). 

Who should not get the flu jab (or should use caution)

The second group of people for whom the jab may not be recommended are those who have experienced significant allergic reactions to flu vaccines or to any of the vaccine’s components. According to official guidance:

“You only cannot have the vaccine if you've had a serious allergic reaction to a previous dose of the vaccine or an ingredient in the vaccine. Some of the flu vaccines used in the UK contain egg protein. Tell the person vaccinating you if you have an egg allergy.” (NHS) 

Because some flu vaccines are produced using egg-based processes, individuals with severe egg allergies should make sure the vaccinator is aware and consider alternative formulations (if available) that avoid egg protein. 

Who is eligible for a free NHS flu vaccine?

The vaccine is prioritized for those at higher risk of complications. The following groups are eligible for free flu jabs under the NHS programme:

• People aged 65 or over by 31 March 2026 

• Individuals with certain long-term health conditions (e.g. respiratory, heart, liver, neurological disorders) 

• Pregnant women, at any stage of pregnancy Residents of care homes 

• Main carers for older or disabled people, or those receiving a carer’s allowance People living with someone who has a weakened immune systemFrontline health and social care workers (offered via employers) 

The 2025–2026 national flu immunisation programme states that there are no changes to the eligibility cohorts compared to previous seasons. 

How and where to get your flu vaccine

Eligible individuals aged 18 or over can schedule their jab via their GP surgery, or online using the NHS App. Some pharmacies also provide walk-in vaccinations, particularly starting from October 1 onward. 

If you’re uncertain whether your condition qualifies you for the free jab, your GP can help assess your eligibility. 

Possible side effects & vaccine effectiveness

After vaccination, some people may experience mild side effects. These usually resolve within one to two days and can include soreness around the injection site, general achiness, or a slight rise in temperature. 

The flu vaccine typically needs up to 14 days to confer full protection. While it does not guarantee that you will not get the flu, getting vaccinated usually results in a milder illness if you do become infected, and it helps you recover more rapidly. 

Additional considerations and recent context

• Vaccine selection for 2025–2026: For the upcoming season, the Joint Committee on Vaccination and Immunisation (JCVI) has advised that all available flu vaccines in the UK be trivalent, containing two influenza A strains and one B strain. Notably, the adjuvanted inactivated influenza vaccine (aIIV), previously reserved for those aged 65 and over, is now licensed from age 50 and over. 

• Importance of uptake: The NHS has warned that, cumulatively, influenza has led to at least 18,000 deaths in England over the past two winters, reinforcing the critical role of vaccination in preventing mortality and reducing strain on health services. 

• Staff uptake concerns: In recent seasons, flu vaccine coverage among frontline NHS staff has dropped dramatically, reaching its lowest level in nearly 15 years — around 37.5%. This downward trend is raising concerns about workforce capacity during winter respiratory surges. 

• Timing considerations: Although vaccination ideally begins in autumn, it remains effective if administered later in the winter, especially for those who missed earlier opportunities.