Influenza Vaccination

Authored by Dr Hayley Willacy , Reviewed by Dr Sarah Jarvis MBE on
This article is for Medical Professionals

Professional Reference articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use. You may find the Influenza and Flu-like Illness article more useful, or one of our other health articles.

Influenza is a major cause of morbidity and mortality each year in the UK. Vaccination has been available since the late 1960s. It is offered annually to patients aged 65 and all those aged 6 months and over in clinical risk groups identified by the Department of Health (DH).

In the 2017/18 flu season, flu vaccine should also be offered to all children who are aged 2-8 years of age (but not 9 years or older) on 31 August 2017 and to all primary school-aged children in former primary school pilot areas.

The World Health Organization (WHO) monitors influenza viruses throughout the world and recommends which strains are to be included in the current year's vaccine.

For the 2017/18 flu season (northern hemisphere winter) it is recommended that trivalent vaccines contain the following:

  • An A/Michigan/45/2015 (H1N1)pdm09-like virus.
  • An A/Hong Kong/4801/2014 (H3N2)-like virus.
  • A B/Brisbane/60/2008-like virus.

Quadrivalent vaccines should contain the above three viruses and a B/Phuket/3073/2013-like virus.

The UK generally uses trivalent vaccines (against two strains of influenza A and one of B)[1]but practices can choose the quadrivalent option.

  • Protection may be less in the elderly but immunisation has been shown to reduce the incidence of bronchopneumonia, mortality and hospital admission.
  • In children, Fluenz Tetra® (which is a live attenuated quadrivalent vaccine) has been shown to provide greater protection than the inactivated vaccine[1].
  • The vaccine needs to be given annually to provide protection from the antigenically changed nature of the prevailing virus. In the event of a major antigenic shift liable to cause an epidemic or pandemic, it is likely that a monovalent vaccine would be prepared.
  • Immunisation should be carried out between September and early November. Although most cases occur from mid-November, it is not unknown for the influenza season to start earlier.
  • Vaccines are normally given intramuscularly (IM) into the upper arm or anterolateral thigh.
  • Fluenz Tetra® is a nasal spray used for children aged 2-18 years.
  • If patients have a bleeding disorder (eg, haemophilia), deep subcutaneous injection is appropriate.
  • Children require a second dose of vaccine four weeks after the first, if they are receiving the vaccine for the first time, to achieve optimum antibody levels.
  • Influenza vaccine can be given with other vaccines, preferably in different limbs. If both vaccines have to be given in the same limb, the sites should be at least 2.5 cm apart[1].
  • The batch numbers and sites of the vaccines should be recorded in the patient's notes.
  • If the vaccine is given for employment purposes, the employer should also keep a record[1].

The percentages for national vaccine uptake in 2016/2017 were as follows[2]:

  • For those aged 65 years and over: 70.5%. This was a slight decrease from 71.0% in 2015/16; however, the number of vaccinations has increased overall.
  • For those aged 6 months to under 65 years in one or more clinical at-risk groups: uptake was 48.6%; this increased from 45.1% in 2015/16, with the total number of vaccinations similar.
  • For clinical at-risk uptake by age: ranged from 19.5% in the 6 months to under 2 years age category to 50.0% in the 2 to under 5 years age category.
  • For clinical at-risk group(s): uptake ranged from 38.2% in patients with asplenia to 64.7% in patients with diabetes.
  • For all pregnant women: uptake was 44.9%; this increased from 42.3% in 2015/16.
  • For all the children cohorts: those aged 2, 3 and 4 years have seen an increase in uptake as well as an increase in the actual number of vaccinations given compared to last year.
  • For all 2-year-olds: was 38.9%.
  • For all 3-year-olds: was 41.5%.
  • For all 4-year olds: was 33.9%.
  • Uptake for carers: was 41.9%.

The 2016 to 2017 season saw 63.2% of all frontline healthcare workers reported to have received the 2016 to 2017 seasonal influenza vaccine in England[3]. This is a significant increase in uptake compared with 50.6% of all frontline workers who received the seasonal influenza vaccine in the 2015 to 2016 season.

The most recent report of vaccine effectiveness (against hospitalisation of those aged over 65 years) against influenza A was 42%[4]. It was 59%, 48%, 43% and 39% in patients with diabetes mellitus, cancer, lung and heart disease, respectively. Adjusted effectiveness against influenza B was 52%. It was 62%, 60% and 36% in patients with diabetes mellitus, lung and heart disease, respectively. Overall, 2015/16 estimates against hospitalised influenza in elderly people were moderate against influenza A and B, including among those with diabetes mellitus, cancer, lung or heart diseases.

  • Store at 2-8°C and protect from light.
  • Discard if frozen.
  • Extremes of temperature can reduce potency. Freezing can cause hairline cracks in the container.
  • All vaccines are supplied in the inactive form in pre-filled syringes (or a nasal applicator) which should be shaken before use[1]. Dispose of the vaccination equipment in a sealable, puncture-proof sharps box (UN-approved BN7390).

Most of the currently available vaccines are grown in embryonic hens' eggs and then chemically inactivated and purified. There are three types available[1]:

  • 'Split virion, inactivated' or 'disrupted virus' vaccines - the whole virus is inactivated by exposing to organic solvents or detergents.
  • 'Surface antigen, inactivated' vaccines - these contain haemagglutinin and neuraminidase antigens prepared from disrupted viruses.
  • A live attenuated vaccine - Fluenz Tetra®, which is preferred for children aged 2-18 years because it provides a higher level of protection.

There is no difference between the first two types of vaccines in efficacy or adverse reactions. Being inactivated, they do not cause the diseases against which they protect. The live attenuated vaccine has been shown to have increased efficacy in children aged 2-18 years[1].

Children not in a clinical risk group only require one dose of the vaccine. Children in clinical risk groups aged 2 years or older but under 9 years who have not received influenza vaccine before should receive a second dose of vaccine at least four weeks later.

Immunocompetent patients

  • Immunocompetent adults, including pregnant women, and children aged 13 years and over should be given a single dose of trivalent vaccine.
  • Children NOT in clinical risk groups only require one dose of vaccine.
  • Children in clinical risk groups aged 2 to under 9 years who have not received influenza vaccine before should receive a second dose of vaccine at least four weeks later.
  • Vaccinated children should avoid contact with severely immunocompromised individuals for two weeks after vaccination.

Immunocompromised patients

Immunocompromised patients (including HIV infection, regardless of CD4 count) should be given influenza vaccine in accordance with the recommendations below. They may not make a full antibody response, so protection may not be as high as for immunocompetent patients. Consideration should also be given to vaccinating household contacts of immunocompromised patients, ie those sharing living accommodation on most days over the winter.

Immunocompromised children, and those living in close contact with those who are immunocompromised, should be offered inactivated vaccine and not live vaccine.

People at risk of influenza

The national policy is that influenza vaccine should be offered to the following groups:

  • All those aged 65 years and over.
  • Residents of nursing or residential homes for the elderly and other long-stay facilities.
  • Carers of persons whose welfare may be at risk if the carer falls ill.
  • All those aged 6 months or over in a clinical risk group (listed below).

In 2012, the Joint Committee on Vaccination and Immunisation (JCVI) recommended that the programme should be extended to all children aged 2-16 years. The phased introduction of this extension began in 2013 with the inclusion of children aged 2 and 3 years in the routine programme.

Clinical risk groupsExamples (decision based on clinical judgement)
Chronic respiratory disease
  • Chronic obstructive pulmonary disease (COPD), including chronic bronchitis and emphysema; bronchiectasis, cystic fibrosis, interstitial lung fibrosis, pneumoconiosis and bronchopulmonary dysplasia (BPD).
  • Asthma - with disease which requires continuous or repeated use of inhaled or systemic steroids or with previous exacerbations requiring hospital admission.
  • Children who have previously been admitted to hospital for lower respiratory tract disease.
Chronic heart disease
  • Congenital heart disease.
  • Hypertension with cardiac complications.
  • Chronic heart failure.
  • Individuals requiring regular medication and/or follow-up for coronary heart disease.
Kidney disease
  • Chronic kidney disease.
  • Nephrotic syndrome.
  • Renal transplantation.
Chronic liver disease
  • Cirrhosis.
  • Biliary atresia.
  • Chronic hepatitis.
Chronic neurological disease
  • Stroke.
  • Transient ischaemic attack (TIA).
  • Type 1 diabetes.
  • Type 2 diabetes requiring insulin or oral hypoglycaemic drugs.
  • Diet-controlled diabetes.
  • Immunosupression due to disease or treatment.
  • Patients undergoing chemotherapy leading to immunosuppression.
  • Asplenia or splenic dysfunction.
  • HIV infection.
  • Individuals treated with, or likely to be treated with, systemic steroids for more than a month at a dose equivalent to prednisolone at 20 mg or more per day (any age) or, for children under 20 kg, a dose of 1 mg or more per kg per day.
Some immunocompromised patients may have a suboptimal immunological response to the vaccine.

All pregnant women should receive the trivalent seasonal influenza vaccine.

The target groups for a one-off pneumococcal vaccination are very similar (see the separate Pneumococcal Vaccination article), so often both are given together in 'flu clinics'.

  • Those living in long-stay residential care homes or other long-stay care facilities, where rapid spread is likely to follow introduction of infection and cause high morbidity and mortality (this does not include prisons, young offender institutions, university halls of residence, etc).
  • Those who are in receipt of a carer's allowance, or those who are the main carer for an elderly or disabled person whose welfare may be at risk if the carer falls ill. This should be given on an individual basis, at the GP's discretion, in the context of other clinical risk groups in their practice.

GPs should take into account the risk of influenza infection exacerbating any underlying disease that a patient may have, as well as the risk of serious illness from influenza itself. GPs should consider on an individual basis the clinical needs of their patients, including individuals with:

  • Multiple sclerosis and related conditions.
  • Hereditary and degenerative diseases of the central nervous system.

NB: Individuals working closely with poultry are no longer thought to be high-risk.

Employers - eg, healthcare trusts and nursing and care homes - should offer influenza vaccination to staff directly involved in patient care as an adjunct to good infection control procedures:

  • Clinicians, midwives and nurses, paramedics and ambulance drivers.
  • Occupational therapists, physiotherapists and radiographers.
  • Primary care providers such as GPs, practice nurses and district nurses.
  • Staff who look after older people in nursing and care homes.

Vaccination of healthy children

In the 2017/18 flu season, flu vaccine should also be offered to all children who are aged 2-8 years old (but not 9 years or older) on 31 August 2017 and to all primary school-aged children in former primary school pilot areas. This is different from last year in two ways:

  • Reception Year children (aged 4-5 years) will now be offered flu vaccination in their reception class, rather than at their general practice surgery.

  • Children in School Year 4 (aged 8-9 years) will be included in the programme this year as part of the phased roll-out of the children's programme.

There are few contra-indications[1]. When in doubt, seek the guidance of a local communicable disease consultant, paediatrician or immunisation co-ordinator. Vaccine should not be given to patients with:

  • A confirmed anaphylactic reaction to a previous dose of the vaccine.
  • A confirmed anaphylactic reaction to any component of the vaccine.

Egg allergy: routine vaccine should not be given where there is a confirmed anaphylactic hypersensitivity to egg products, as the vaccines are prepared in hens' eggs. It has now been advised that, except for those with severe anaphylaxis to egg, which has previously required intensive care, children with an egg allergy can be safely vaccinated with Fluenz Tetra®. An egg-free vaccine is available and can be given.

A careful history should rule out previous non-life-threatening reactions (eg, rash, or reactions which were not truly anaphylactic). Seek the advice of a specialist when in doubt.

In addition, Fluenz Tetra® (live attenuated vaccine) is contra-indicated for those who[5]:

  • Are clinically severely immunodeficient secondary to a condition or immunosuppressive therapy - eg, leukaemias, HIV (not on active antiretroviral therapy - ART) and high-dose corticosteroids.
  • Are receiving salicylate therapy.
  • Are severely asthmatic (level 4 or above) or actively wheezing at the time of vaccination.
  • Intercurrent illness - vaccination may be postponed in the event of an acute illness, but minor illness without pyrexia or systemic upset should not be a reason for delay.
  • Premature infants - at-risk premature infants should have vaccination at the appropriate chronological age, preferably with thiomersal-free vaccine.
  • HIV infection - immunosuppressed patients should be given the vaccine, irrespective of CD4 count. A full antibody response may not be produced. See above also for Fluenz Tetra®.

NB: side-effects may be more pronounced if both seasonal influenza and swine influenza vaccinations are co-administered.

  • Angio-oedema, urticaria, bronchospasm and anaphylaxis can occur. This is an immediate reaction, usually due to hypersensitivity to residual egg protein.
  • Neuralgia, paraesthesiae, convulsions and transient thrombocytopenia have been reported rarely[1].
  • Guillain-Barré syndrome has (very rarely) been reported (1-2 cases per million vaccinated people)[6].
  • Encephalomyelitis, neuritis (mainly optic) and vasculitis have also (very rarely) been reported but a definite causal relationship with influenza vaccine has not been established.
  • All suspected reactions in children and severe suspected reactions in adults should be reported using the Yellow Card Scheme to the Commission on Human Medicines[7].

NB: The National Institute for Health and Care Excellence (NICE) has stated that zanamivir and oseltamivir can be used for the prevention and treatment of influenza - but are not a substitute for vaccination[8].

Further reading and references

  1. Influenza: the Green Book, Chapter 19; Public Health England (August 2015)

  2. Seasonal influenza vaccine uptake in GP patients: winter season 2016 to 2017; Final data for 1 September 2016 to 31 January 2017, Public Health England (May 2017)

  3. Seasonal influenza vaccine uptake in healthcare workers (HCWs) in England: Winter season 2016 to 2017, Public Health England (May 2017)

  4. Rondy M, Larrauri A, Casado I, et al; 2015/16 seasonal vaccine effectiveness against hospitalisation with influenza A(H1N1)pdm09 and B among elderly people in Europe: results from the I-MOVE+ project. Euro Surveill. 2017 Jul 2722(30). pii: 30580. doi: 10.2807/1560-7917.ES.2017.22.30.30580.

  5. Summary of Product Characteristics (SPC) - Fluenz® nasal spray suspension Influenza vaccine (live attenuated nasal); AstraZeneca UK. Updated August 2015.

  6. Fiore AE, Bridges CB, Cox NJ; Seasonal influenza vaccines. Curr Top Microbiol Immunol. 2009333:43-82. doi: 10.1007/978-3-540-92165-3_3.

  7. Online reporting site for the Yellow Card Scheme; Medicines and Healthcare products Regulatory Agency (MHRA)

  8. Amantadine, oseltamivir and zanamivir for the treatment of influenza; NICE Technology Appraisal Guidance, February 2009

I had flu symptoms like fever, night sweats, cough, chills, white toung, 1 ulcer below young and 1 side neck is little swollen for week. My influenza report came positive. All symptoms were cleared...

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