Children aged between 2 and 16 in the UK are offered the flu vaccine as a nasal spray rather than an injection, and the reason is scientific rather than to avoid pain or anxiety, according to a GP.
Dr Shruti Nathwani, an NHS General Practitioner with paediatric training, shared the explanation on Instagram, where she is known as @thechildrensmedic. She said the difference comes down to how the two methods stimulate the immune system.
How the nasal spray works differently
Dr Nathwani explained: "The main difference is how they stimulate the immune system. The nasal vaccine works in the nose, where flu first enters, so it creates local immunity in the nasal lining as well as antibodies and T cell responses elsewhere in the body."
She added: "The injection mainly produces antibodies circulating in the blood. Both protect against flu, but they create immunity in slightly different ways."
There is also a flu vaccine available for some children, particularly those aged between six months and 23 months. Dr Nathwani said: "Clinical trials in infants aged 6–23 months found an unexpected risk of wheezing and higher hospitalisation rates, which is why they get the injection instead."
Live vaccine and eligibility
The nasal spray is a live vaccine, and some children may not be eligible for it if they have an underlying condition. Dr Nathwani said: "The live virus in the vaccine isn’t the same as catching flu. They’re weakened and designed to work mainly in the cooler nose, where they trigger your child’s immune response. This is very different from catching flu itself."
She also noted that asthma does not automatically rule out the nasal spray, but current wheezing, needing extra reliever inhaler in the last 72 hours, or some cases of severe asthma may mean it is not suitable. The UK has updated its guidance to state that an egg allergy is no longer a contraindication with the spray, but parents should inform their vaccination team about any allergies beforehand.
Side effects and who cannot have the spray
According to Dr Nathwani, some children may experience side effects such as reduced appetite, a runny nose, headaches or tiredness after the appointment. She also said children can sometimes shed a small amount of the virus when in close contact with people, stating: "Transmission to others is very unlikely, but tell the vaccination team if your child has close contact with someone who is severely immunocompromised."
Children who cannot have the nasal spray include those under 2 years of age, those who have had a serious allergic reaction (anaphylaxis) to a previous dose or an ingredient in the spray including gelatine, neomycin or gentamicin, those with a severely weakened immune system or who live with someone who has one, children with asthma treated with long-term steroid tablets or who have needed intensive care, those who have had a flare-up of asthma symptoms in the past 72 hours, and children having salicylate therapy.
