Vaccine - Influenza

Seasonal influenza still accounts for a significant morbidity and mortality in the UK each winter, with the influenza season typically starting in the middle of November. This may vary year from year so it is recommended that vaccination occurs between September and early November. There are three types of influenza virus; A, B and C. Types A and B account for the majority of clinical disease. 
 
Prior to 2013 flu vaccination was only offered to the elderly and at risk groups. 
 
Remember that the type of vaccine given routinely to children and the one given to the elderly and at risk groups is different (live vs. inactivated) - this explains the different contraindications 
 
 

Children 

 
A new NHS influenza vaccination programme for children was announced in 2013. There are three key things to remember about the children's vaccine: 
 

  • it is given intranasally 

  • the first dose is given at 2-3 years, then annually after that 

  • it is a live vaccine (cf. injectable vaccine below) 

 
Some other points 
 

  • children who were traditionally offered the flu vaccine (e.g. asthmatics) will now be given intranasal vaccine unless this is inappropriate, for example if they are immunosuppressed. In this situation the inactivated, injectable vaccine should be given 

  • only children aged 2-9 years who have not received an influenza vaccine before need 2 doses 

  • it is more effective than the injectable vaccine 

 
Contraindications 
 

  • immunocompromised 

  • aged < 2 years 

  • current febrile illness or blocked nose/rhinorrhoea 

  • current wheeze (e.g. ongoing viral-induced wheeze/asthma) or history of severe asthma (BTS step 4) 

  • egg allergy 

  • pregnancy/breastfeeding 

  • if the child is taking aspirin (e.g. for Kawasaki disease) due to a risk of Reye's syndrome 

 
Side-effects 
 

  • blocked-nose/rhinorrhoea 

  • headache 

  • anorexia 

 
 

Adults and at-risk groups 

 
Current vaccines are trivalent and consist of two subtypes of influenza A and one subtype of influenza B. 
 
The Department of Health recommends annual influenza vaccination for all people older than 65 years, and those older than 6 months if they have: 
 

  • chronic respiratory disease (including asthmatics who use inhaled steroids) 

  • chronic heart disease (heart failure, ischaemic heart disease, including hypertension if associated with cardiac complications) 

  • chronic kidney disease 

  • chronic liver disease: cirrhosis, biliary atresia, chronic hepatitis 

  • chronic neurological disease: (e.g. Stroke/TIAs) 

  • diabetes mellitus (including diet controlled) 

  • immunosuppression due to disease or treatment (e.g. HIV) 

  • asplenia or splenic dysfunction 

  • pregnant women 

  • adults with a body mass index >= 40 kg/m² 

 
Other at risk individuals include: 
 

  • health and social care staff directly involved in patient care (e.g. NHS staff) 

  • those living in long-stay residential care homes 

  • carers of the elderly or disabled person whose welfare may be at risk if the carer becomes ill (at the GP's discretion) 

 
The influenza vaccine 
 

  • it is an inactivated vaccine, so cannot cause influenza. A minority of patients however develop fever and malaise which may last 1-2 days 

  • should be stored between +2 and +8ºC and shielded from light 

  • contraindications include hypersensitivity to egg protein. 

  • in adults the vaccination is around 75% effective, although this figure decreases in the elderly 

  • it takes around 10-14 days after immunisation before antibody levels are at protective levels