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This Guidelines for Nurses summary of the Green Book chapter 19 on flu covers the disease and vaccination. This summary contains information relevant to practice nurses. For further information, refer to the full guideline.

View the Guidelines summary on flu immunisation: Summary of flu immunisation guidance for England 2021–2022.

The disease

  • Flu is an acute viral infection of the respiratory tract. There are three types of flu virus: A, B, and C. Influenza A and B are responsible for most clinical illness. Flu is highly infectious with a usual incubation period of 1–3 days
  • The disease is characterised by the sudden onset of fever, chills, headache, myalgia, and extreme fatigue. Other common symptoms include a dry cough, sore throat, and stuffy nose
  • For otherwise healthy individuals, flu is an unpleasant but usually self-limiting disease with recovery usually within 2–7 days. The illness may be complicated by (and may present as) bronchitis, secondary bacterial pneumonia or, in children, otitis media
  • Flu can be complicated more unusually by meningitis, encephalitis, or meningoencephalitis
  • The risk of serious illness from flu is higher amongst children under 6 months of age, older people, and those with underlying health conditions such as respiratory or cardiac disease, chronic neurological conditions, or immunosuppression, and pregnant women
  • Flu during pregnancy may also be associated with perinatal mortality, prematurity, smaller neonatal size, and lower birth weight.

The flu vaccination

  • All but one of the flu vaccines available in the UK are inactivated and cannot cause clinical flu in those that are vaccinated. One vaccine, the live attenuated influenza vaccine (LAIV) Fluenz® Tetra contains live viruses that have been attenuated (weakened) and adapted to cold so that they can only replicate at the lower temperatures found in the nasal passage
  • These live viruses cannot replicate efficiently elsewhere in the body but may cause mild coryzal symptoms
  • The inactivated vaccines are all administered by intramuscular injection. The LAIV is administered by nasal spray
  • Most of the vaccines are prepared from viruses grown in embryonated hens’ eggs although cell-based production is likely to become more important in future years
  • The LAIV is also thought to provide broader protection than inactivated vaccines, and therefore has potential to offer better protection against strains that have undergone antigenic drift compared to the original virus strains in the vaccine
  • After immunisation, protective immune responses may be achieved within 14 days. Although flu activity is not usually significant in the UK before the middle of November, the flu season can start early, and therefore the ideal time for immunisation is between September and early November. Protection afforded by the vaccine is thought to last for at least one flu season. However, as the level of protection provided in subsequent seasons is likely to be low and there may be changes to the circulating strains from one season to the next, annual revaccination is important
  • A list of the flu vaccines available in the UK is published ahead of the flu season in the national immunisation programme plan.


For further information on storage, also refer to chapter 3 of the Green Book. 

  • Vaccines should be stored in the original packaging at +2°C–8°C and protected from light. All vaccines are sensitive to some extent to heat and cold. Heat speeds up the decline in potency of most vaccines, thus reducing their shelf life. Efficacy, safety, and quality may be adversely affected if vaccines are not stored at the temperatures specified in the license. Freezing may cause increased reactogenicity and loss of potency for some vaccines and can also cause hairline cracks in the container, leading to contamination of the contents
  • Fluenz® Tetra may be left out of the refrigerator/removed from the cold chain for a maximum period of 12 hours at a temperature not above 25°C as indicated in the summary of product characteristics (SPC). If the vaccine has not been used after this 12-hour period, it should be disposed of.


  • Inactivated flu vaccines for intramuscular administration are supplied as suspensions in prefilled syringes. They should be shaken well before they are administered
  • Fluenz® Tetra is supplied as a nasal spray suspension in a special applicator.

Dosage and schedule

  • The dosages and schedules for flu vaccines should be given according to the recommendations for use of the vaccine (see section on Recommendations for the use of the vaccines)
  • Some of the SPCs for intramuscular (IM) inactivated flu vaccines indicate that young children can be given either a 0.25 ml or a 0.5 ml dose. The Joint Committee on Vaccination and Immunisation (JCVI) has advised that where these alternative doses are indicated in the SPC, the 0.5 ml dose of IM inactivated flu vaccine should be given to infants aged 6 months or older and young children because there is evidence that this dose is effective in young children
  • Children aged 6 months to under 9 years who are in clinical risk groups and have not received flu vaccine previously should be offered a second dose of vaccine. The JCVI has advised that children aged 2 years to under 9 years of age who are not in a clinical risk group, only require a single dose of LAIV irrespective of whether they have received flu vaccine previously. This advice differs from that in the SPC for Fluenz® Tetra. Children who have received one or more doses of any flu vaccine before (including pandemic monovalent influenza A(H1N1)v vaccine) should be considered as previously vaccinated (see the Children section under Recommendations for the use of the vaccines).


  • The inactivated flu vaccines should normally be given into the upper arm (or anterolateral thigh in infants) preferably by IM injection. Influenza vaccines licensed for IM or subcutaneous administration may alternatively be administered by the subcutaneous route 
  • There is a lack of evidence that the subcutaneous route of vaccination is any safer than the IM route in people taking anticoagulants. The subcutaneous route can itself be associated with an increase in localised reactions
  • Individuals on stable anticoagulation therapy, including individuals on warfarin who are up-to-date with their scheduled International Normalised Ratio (INR) testing and whose latest INR was below the upper threshold of their therapeutic range, can receive IM vaccination. A fine needle (23 or 25 gauge) should be used for the vaccination, followed by firm pressure applied to the site (without rubbing) for at least 2 minutes. If in any doubt, consult with the clinician responsible for prescribing or monitoring the individual’s anticoagulant therapy
  • Individuals with bleeding disorders may be vaccinated intramuscularly if, in the opinion of a doctor familiar with the individual’s bleeding risk, vaccines or similar small-volume IM injections can be administered with reasonable safety by this route. If the individual receives medication/treatment to reduce bleeding, for example treatment for haemophilia, IM vaccination can be scheduled shortly after such medication/treatment is administered. A fine needle (23 or 25 gauge) should be used for the vaccination, followed by firm pressure applied to the site (without rubbing) for at least 2 minutes. The individual/parent/carer should be informed about the risk of haematoma from the injection
  • The LAIV is administered by the intranasal route (Fluenz® Tetra) and is supplied in an applicator that allows a divided dose to be administered in each nostril (total dose of 0.2 ml, 0.1 ml in each nostril)
  • The device allows intranasal administration to be performed without the need for additional training
  • Administration of either dose does not need to be repeated if the patient sneezes or blows their nose following administration
  • As heavy nasal congestion might impede delivery of the vaccine to the nasopharyngeal mucosa, deferral of administration until resolution of the nasal congestion should be considered, or if appropriate, an alternative intramuscularly administered flu vaccine
  • Inactivated flu vaccines can be given at the same time as other vaccines
  • The LAIV can also be given at the same time as other live or inactivated vaccines. Although it was previously recommended that, where vaccines cannot be administered simultaneously; a 4-week interval should be observed between live viral vaccines, the JCVI has advised that no specific intervals need to be observed between the live attenuated intranasal flu vaccine and other live vaccines (see chapter 6 of the Green Book)
  • IM vaccines should be given at separate sites, preferably in a different limb. If given in the same limb, they should be given at least 2.5 cm apart
  • As a wide variety of flu vaccines are on the UK market each year, it is especially important that the exact brand of vaccine, batch number, and site at which each vaccine is given is accurately recorded in the patient records
  • Where the vaccine is given for occupational reasons, it is recommended that the employer keep a vaccination record
  • It is important that vaccinations given either at a general practice or elsewhere (for example, at community pharmacies, or antenatal clinics) are recorded on appropriate health records for the individual (using the appropriate clinical code) in a timely manner. If given outside of general practice, a record of vaccination should be returned to the patient’s general practice to allow clinical follow up and to avoid duplicate vaccination.

Recommendations for the use of the vaccines

  • GPs are required to proactively identify all those for whom flu immunisations are indicated and to compile a register of those patients for whom flu immunisation is recommended. Sufficient vaccine can then be ordered in advance and patients can be invited to planned immunisation sessions or appointments
  • Given that some flu vaccines are restricted for use in particular age groups, the SPCs for individual products should always be referred to when ordering vaccines to ensure that they can be given appropriately to particular patient age groups
  • Patients should be advised that many other organisms cause respiratory infections similar to flu during the flu season, for example, the common cold and respiratory syncytial virus. flu vaccine will not protect against these diseases
  • Flu vaccine should be offered, ideally before flu viruses start to circulate, to:
    • all those aged 65 years or older (for definition please see the annual flu letter for the coming/current season)
    • all those aged 6 months or older in the clinical risk groups shown in Table 1
    • children not in clinical risk groups that are eligible for vaccination as part of the ongoing phased roll out of the extension of the programme to all children aged 2 to less than 17 years old.

Note: see the respective annual flu letters for England and the devolved administrations (Scotland, Wales, and Northern Ireland) for specific details on the cohorts of children that are eligible for flu vaccination.

Table 1: Clinical risk groups who should receive the flu immunisation—flu vaccine should be offered to people in the clinical risk categories set out
Clinical risk categoryExamples (this list is not exhaustive and decisions should be based on clinical judgement)

Chronic respiratory disease

Asthma that requires continuous or repeated use of inhaled or systemic steroids or with previous exacerbations requiring hospital admission


Chronic obstructive pulmonary disease including chronic bronchitis and emphysema; bronchiectasis, cystic fibrosis, interstitial lung fibrosis, pneumoconiosis, and bronchopulmonary dysplasia


Children who have previously been admitted to hospital for lower respiratory tract disease


See precautions section on live attenuated influenza vaccine

Chronic heart disease

Congenital heart disease, hypertension with cardiac complications, chronic heart failure, individuals requiring regular medication and/or follow-up for ischaemic heart disease

Chronic kidney disease

Chronic kidney disease at stage 3, 4, or 5, chronic kidney failure, nephrotic syndrome, kidney transplantation

Chronic liver disease

Cirrhosis, biliary atresia, chronic hepatitis

Chronic neurological disease (included in the DES directions for Wales)

Stroke, transient ischaemic attack. Conditions in which respiratory function may be compromised due to neurological disease (e.g. polio syndrome sufferers). Clinicians should offer immunisation, based on individual assessment, to clinically vulnerable individuals including those with cerebral palsy, learning disabilities, multiple sclerosis and related or similar conditions; or hereditary and degenerative disease of the nervous system or muscles; or severe neurological disability


Type 1 diabetes, type 2 diabetes requiring insulin or oral hypoglycaemic drugs, diet controlled diabetes

Immunosuppression (see contraindications and precautions section on live attenuated influenza vaccine)

Immunosuppression due to disease or treatment, including patients undergoing chemotherapy leading to immunosuppression, bone marrow transplant, HIV infection at all stages, multiple myeloma, or genetic disorders affecting the immune system (e.g. IRAK-4, NEMO, complement disorder)


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


It is difficult to define at what level of immunosuppression a patient could be considered to be at a greater risk of the serious consequences of flu and should be offered flu vaccination. This decision is best made on an individual basis and left to the patient’s clinician


Some immunocompromised patients may have a suboptimal immunological response to the vaccine

Asplenia or dysfunction of the spleen

This also includes conditions such as homozygous sickle cell disease and coeliac syndrome that may lead to splenic dysfunction

Pregnant women

Pregnant women at any stage of pregnancy (first, second, or third trimesters)


See precautions section on live attenuated influenza vaccine

Morbid obesity (class III obesity)[A]

Adults with a body mass index ≥40 kg/m²

[A] Many of this patient group will already be eligible due to complications of obesity that place them in another risk category

Other groups

  • The list in Table 1 is not exhaustive, and the medical practitioner should apply clinical judgement to take into account the risk of flu exacerbating any underlying disease that a patient may have, as well as the risk of serious illness from flu itself. Flu vaccine should be offered in such cases even if the individual is not in the clinical risk groups specified in Table 1
  • Vaccination should also be offered to household contacts of immunocompromised individuals, that is, individuals who expect to share living accommodation on most days over the winter and therefore for whom continuing close contact is unavoidable. This may include carers 
  • In addition to those listed in Table 1, immunisation should be provided to healthcare and social care workers in direct contact with patients/clients to protect them and to reduce the transmission of flu within health and social care premises, to contribute to the protection of individuals who may have a suboptimal response to their own immunisations, and to avoid disruption to services that provide their care. This would include: 
    • health and social care staff directly involved in the care of their patients or clients
    • 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 of an elderly or disabled person whose welfare may be at risk if the carer falls ill. Vaccination should be given on an individual basis at the GP’s discretion in the context of other clinical risk groups in their practice
    • others involved directly in delivering health and social care such that they and vulnerable patients/clients are at increased risk of exposure to flu (further information is provided in guidance from UK health departments).


  • The JCVI has advised the use of different dosage schedules of flu vaccine for children depending on their age, the clinical indications, the type of vaccine offered, and whether they have received flu vaccine previously. This advice differs from some of the SPCs.

Children aged 2 to less than 17 years old NOT in clinical risk groups

  • Starting from September 2013, an extension of the programme to all children aged 2 to less than 17 years old is being phased in from the youngest age groups. Please see the respective annual flu letters for England and the devolved ddministrations for the cohorts of children that are eligible for flu vaccination for the coming/current season
  • A single dose of LAIV should be offered per season, unless contraindicated, irrespective of whether flu vaccine has been received previously.

Children aged 6 months to less than 2 years of age IN clinical risk groups

  • These children should be offered the recommended inactivated quadrivalent flu vaccine. Those who have not received flu vaccine previously should be offered a second dose of vaccine, at least 4 weeks later. The inactivated flu vaccines are interchangeable; the second dose, if required, should be given at least 4 weeks after the first dose in accordance with the manufacturer’s SPC for that vaccine.

Children aged 2 to less than 18 years of age IN clinical risk groups

  • Children aged 2 years to less than 18 years in clinical risk groups should be offered LAIV unless it is medically contraindicated or otherwise unsuitable (see contraindications and precautions sections). Those children who have never received flu vaccine before and are aged between 2 and less than 9 years should be offered a second dose of LAIV at least 4 weeks later. If LAIV is unavailable for this second dose (due to batch expiry) an inactivated flu vaccine can be given
  • For those children in clinical risk groups for whom LAIV is medically contraindicated, a suitable quadrivalent inactivated flu vaccine should be offered. The quadrivalent vaccine has both lineages of flu B and may therefore provide better protection against the circulating B strain(s) than trivalent inactivated flu vaccines
  • Children aged 2 to less than 9 years old who have not received flu vaccine previously should be offered a second dose of the vaccine at least 4 weeks later
  • The inactivated flu vaccines are interchangeable; the second dose, if required, should be given at least 4 weeks after the first dose in accordance with the manufacturer’s SPC for that vaccine
  • Table 2 summarises the advice on flu vaccination for children.

Preterm infants

  • It is important that preterm infants who have risk factors have their immunisations at the appropriate chronological age. Flu immunisation should be considered after the child has reached 6 months of age.
Eligible cohortVaccine available: children in clinical risk groups[A]
Vaccine available: children not in clinical risk groups[B]
Table 2: Flu vaccination for children under 18 years old

6 months to less than 2 years old

Offer suitable quadrivalent inactivated flu vaccine

Not applicable

Children aged 2 years to less than 18 years old[B]

Offer LAIV (Fluenz® Tetra) (unless medically contraindicated[C])

Offer LAIV (Fluenz® Tetra)

[A] Children in clinical risk groups aged 6 months to less than nine years who have not received flu vaccine before should be offered two doses of the appropriate flu vaccine (given at least 4 weeks apart)

[B] Please see the respective annual flu letters for England and the devolved administrations for the cohorts of children not in clinical risk groups that are eligible for flu vaccination for the coming/current season

[C] If LAIV is medically contraindicated or otherwise unsuitable, then offer quadrivalent inactivated flu vaccine.


  • Pregnant women should be offered inactivated flu vaccine as the risk of serious illness from flu is higher in pregnant women. In addition, a number of studies show that flu vaccination during pregnancy provides passive immunity against flu to infants in the first few months of life following birth
  • A review of studies on the safety of flu vaccine in pregnancy concluded that inactivated flu vaccine can be safely and effectively administered during any trimester of pregnancy
  • Whilst there is no evidence of risk with LAIV, inactivated flu vaccines are preferred for those who are pregnant. There is no need, however, to specifically test eligible girls for pregnancy or to advise avoidance of pregnancy in those who have been recently vaccinated.


  • The SPCs for individual products should always be referred to when deciding which vaccine to give. There are very few individuals who cannot receive any flu vaccine. When there is doubt, appropriate advice should be sought promptly from the screening and immunisation team in the NHS England team, a consultant in communicable disease control, or a consultant paediatrician, so that the period the individual is left unvaccinated is minimised
  • None of the flu vaccines should be given to those who have had:
    • a confirmed anaphylactic reaction to a previous dose of the vaccine, or
    • a confirmed anaphylactic reaction to any component of the vaccine (other than ovalbumin—see precautions)
  • Confirmed anaphylaxis is rare (see chapter 8 of the Green Book for further information). Other allergic conditions such as rashes may occur more commonly and are not contraindications to further immunisation. A careful history of the event will often distinguish between true anaphylaxis and other events that are either not due to the vaccine or are not life threatening. In the latter circumstance, it may be possible to continue the immunisation course. Specialist advice must be sought on the vaccines and the circumstances in which they could be given (see chapter 6 of the Green Book for further information). The risk to the individual of not being immunised must be taken into account
  • LAIV should not be given to children or adolescents who are clinically severely immunodeficient due to conditions or immunosuppressive therapy such as: acute and chronic leukaemias; lymphoma; HIV infection not on highly active antiretroviral therapy; cellular immune deficiencies; and high-dose corticosteroids
  • It is not contraindicated for use in children or adolescents with stable HIV infection receiving antiretroviral therapy; or who are receiving topical corticosteroids, inhaled corticosteroids or low-dose systemic corticosteroids, or those receiving corticosteroids as replacement therapy, for example, for adrenal insufficiency
  • It is contraindicated in children and adolescents receiving salicylate therapy (other than for topical treatment of localised conditions) because of the association of Reye’s syndrome with salicylates and wild-type flu infection as described in the SPC for Fluenz® Tetra.


  • Minor illnesses without fever or systemic upset are not valid reasons to postpone immunisation. If an individual is acutely unwell, immunisation may be postponed until they have fully recovered. This is to avoid confusing the differential diagnosis of any acute illness by wrongly attributing any signs or symptoms to the adverse effects of the vaccine.

Immunosuppression and HIV infection

  • Individuals who have immunosuppression and HIV infection (regardless of CD4 count) should be given flu vaccine in accordance with the recommendations and contraindications above. These individuals may not make a full antibody response
  • Consideration should also be given to the flu vaccination of household contacts of immunocompromised individuals, that is, individuals who expect to share living accommodation on most days over the winter and therefore for whom continuing close contact is unavoidable
  • There is a theoretical potential for transmission of LAIV in Fluenz® Tetra to immunocompromised contacts for one to two weeks following vaccination
  • Where close contact with very severely immunocompromised patients (e.g. bone marrow transplant patients requiring isolation) is likely or unavoidable (for example, household members), however, appropriate alternative inactivated flu vaccines should be considered
  • Further guidance is provided by the Royal College of Paediatrics and Child Health, the British HIV Association guidelines on the use of vaccines in HIV-positive adults and the Children’s HIV Association immunisation guidelines.

Severe asthma or active wheezing

  • The JCVI has advised that children with asthma on inhaled corticosteroids may safely be given LAIV, irrespective of the dose prescribed
  • LAIV is not recommended for children and adolescents currently experiencing an acute exacerbation of symptoms including those who have had increased wheezing and/or needed additional bronchodilator treatment in the previous 72 hours. Such children should be offered a suitable inactivated flu vaccine to avoid a delay in protection
  • There are limited safety data in children who require regular oral steroids for maintenance of asthma control, or have previously required intensive care for asthma exacerbation—such children should only be given LAIV on the advice of their specialist. As these children may be at higher risk from flu infection, those who cannot receive LAIV should receive a suitable inactivated flu vaccine 
  • Children with significant asthma and aged under 9 years who have not been previously vaccinated against flu will require a second dose (of either LAIV or inactivated vaccine as appropriate).

Egg allergy

  • In all settings providing vaccination, facilities should be available and staff trained to recognise and treat anaphylaxis (see chapter 8 of the Green Book)
  • Inactivated flu vaccines that are egg-free or have a very low ovalbumin content (<0.12 micrograms/ml—equivalent to <0.06 micrograms for a 0.5 ml dose) are available and studies show they may be used safely in individuals with egg allergy. LAIV (Fluenz® Tetra), which previously had an upper ovalbumin limit of 1.2 mcg/ml, has also been shown to be safe for use in egg-allergic children. The ovalbumin content of LAIV has been further reduced since 2016 (≤0.024 micrograms per 0.2ml dose). The ovalbumin content of flu vaccines will be published prior to the flu season
  • Egg-allergic adults and children over age nine years with egg allergy can also be given the quadrivalent inactivated egg-free vaccine, Flucelvax® Tetra, which is licensed for use in this age group.


  • The JCVI has advised that children with an egg allergy—including those with previous anaphylaxis to egg—can be safely vaccinated with LAIV in any setting (including primary care and schools). The only exception is for children who have required admission to intensive care for a previous severe anaphylaxis to egg; such children are best given LAIV in the hospital setting. LAIV remains the preferred vaccine for this group and the intranasal route is less likely to cause systemic reactions
  • Children with egg allergy but who also have another condition which contraindicates LAIV should be offered an inactivated flu vaccine with a very low ovalbumin content (less than 0.12 mcg/ml)
  • Children in a clinical risk group and aged under 9 years who have not been previously vaccinated against flu will require a second dose (of either LAIV or inactivated vaccine as appropriate).


  • Adult patients can be immunised in any setting using an inactivated flu vaccine with an ovalbumin content less than 0.12 mcg/ml (equivalent to 0.06 micrograms for 0.5 ml dose), excepting those with severe anaphylaxis to egg which has previously required intensive care who should be referred to a specialist for assessment with regard to receiving immunisation in hospital.

Use with antiviral agents against flu

  • There is a potential for flu antiviral agents to lower the effectiveness of the LAIV. Therefore, flu antiviral agents and LAIV should not be administered concomitantly. The LAIV should be delayed until 48 hours following the cessation of treatment with flu antiviral agents
  • Administration of flu antiviral agents within 2 weeks of administration of LAIV may adversely affect the effectiveness of the vaccine.

Exposure of healthcare professionals to LAIV viruses

  • As a precaution, very severely immunosuppressed individuals should not administer LAIV. Other healthcare workers who have less severe immunosuppression, or are pregnant, should follow normal clinical practice to avoid inhaling the vaccine and ensure that they themselves are appropriately vaccinated.

Inadvertent administration of LAIV

  • If an immunocompromised individual receives LAIV then the degree of immunosuppression should be assessed. If the patient is severely immunocompromised, antiviral prophylaxis should be considered, otherwise they should be advised to seek medical advice if they develop flu-like symptoms in the 4 days (the usual incubation period) following administration of the vaccine. If antivirals are used for prophylaxis or treatment, then in order to maximise their protection in the forthcoming flu season, the patient should also be offered inactivated flu vaccine. This can be given straight away.

Adverse reactions

  • Pain, swelling, or redness at the injection site, low grade fever, malaise, shivering, fatigue, headache, myalgia, and arthralgia are among the commonly reported symptoms after IM or intradermal vaccination. A small painless nodule (induration) may also form at the injection site. These symptoms usually disappear within 1–2 days without treatment
  • Nasal congestion/rhinorrhoea, reduced appetite, weakness, and headache are common adverse reactions following administration of LAIV
  • Immediate reactions such as urticaria, angio-oedema, bronchospasm, and anaphylaxis can occur
  • All serious suspected reactions following flu vaccines should be reported to the Medicines and Healthcare products Regulatory Agency using the Yellow Card scheme at yellowcard.mhra.gov.uk
  • The quadrivalent cell cultured inactivated influenza vaccine (QIVc), quadrivalent inactivated influenza vaccine (QIV) and high-dose trivalent inactivated influenza vaccine (TIV-HD) carry a black triangle symbol (▼). This is a standard symbol added to the product information of a vaccine during the earlier stages of its introduction, to encourage reporting of all suspected adverse reactions.

For information on febrile convulsions and fever, refer to the full guideline.

Management of suspected cases, contacts, and outbreaks

  • There are antiviral drugs available that can be used under certain circumstances to either prevent or treat flu. NICE has issued guidance on the use of antiviral drugs for the prevention and treatment of flu at:
    • oseltamivir, amantadine (review), and zanamivir for the prophylaxis of flu
    • amantadine, oseltamivir, and zanamivir for the treatment of flu
  • It is always important to encourage and maintain good hand and respiratory hygiene, which can help to reduce the spread of flu.


  • Demand for flu vaccine sometimes increases unpredictably in response to speculation about flu illness in the community. Therefore, it is recommended that practices order sufficient vaccine for their needs, based on their at-risk registers, well in advance of the immunisation season
  • Information on supplies and how to order vaccines will be given in guidance provides separately by each of the four UK countries—see respective websites for details. LAIV is purchased centrally for eligible children aged two to less than 18 years. For eligible children under 18 years of age where LAIV is medically contraindicated, a suitable inactivated quadrivalent vaccine will be supplied. These vaccines should be ordered as per the usual mechanisms for the routine childhood immunisation programme (also see chapter 3 of the Green Book). Arrangements for supply may differ between England and the devolved administrations 
  • A list of the flu vaccines available in the UK is published ahead of the flu season in the annual flu letter for England.


Full guideline:

Public Health England. Influenza: the green book, chapter 19. October 2020. Available at: gov.uk/government/publications/influenza-the-green-book-chapter-19

Contains public sector information licensed under the Open Government Licence v3.0.

Published date: 20 March 2013.

Last updated: 29 October 2020.