Influenza Vaccine (Surface Antigen, Inactivated)

Registered South African indications:

• Prophylaxis of influenza, particularly indicated in:
  - Persons who are at high risk for influenza and its complications because of underlying medical conditions and who are receiving regular medical care for conditions such as chronic pulmonary and cardiac diseases, chronic renal diseases, diabetes mellitus and similar metabolic disorders and individuals who are immunosuppressed
  - Residents of old age homes, chronic care rehabilitation institutions; 
  - Children on long-term aspirin therapy
  - Medical and nursing staff responsible for the care of high risk cases;
  - Adults and children who are family contacts of high risk cases
  - All persons over the age of 65
  - Any person wishing to protect themselves from the risk of contracting influenza, especially in industrial settings, where large scale absenteeism could cause significant economic losses

Registered South African contraindications

• Hypersensitivity to the active substances, to any of the excipients or to any component that may be present as traces such as eggs (ovalbumin, chicken proteins), formaldehyde, cetyltrimethylammonium bromide, polysorbate 80 and gentamycin
• Persons with febrile illnesses or acute infection should preferably be immunised after the symptoms have disappeared

South African recommendations

Caution in the following patient groups

• Renal impairment
• Hepatic impairment
• Elderly

Anaphylactic events

• Appropriate medical treatment (e.g., adrenalin) and supervision must be readily available

Administration routes

• Should under no circumstances be administered intravascularly

Thrombocytopenia and coagulation disorders

• Administer with caution as bleeding may occur following intramuscular administration

Psychogenic reactions

• Anxiety-related reactions (syncope, hyperventilation, or stress) may occur; ensure procedures are in place to avoid injury from faints

Vaccine efficacy

• May not be effective against all influenza strains or elicit a protective response in all vaccinees; antibody response may be insufficient in immunosuppressed patients

Serological testing

• May interfere with serological testing

Antibiotic hypersensitivity

• Use with caution in patients hypersensitive to gentamycin, polymyxin, or neomycin, as minimal amounts may be present

Simultaneous vaccination

• Adverse events may be aggravated; sensitive individuals should observe a 3-week waiting period unless the influenza season has started

Excipient content

• Contains less than 1 mmol sodium and less than 1 mmol potassium per dose (essentially sodium-free and potassium-free).

Effects on ability to drive and use machines

• Inactivated influenza vaccine has no or negligible influence on the ability to drive and use machines

Forms avail. in South Africa and covered in this monograph: inj

South African registered indications and dosages

Prophylaxis of influenza, particularly indicated in:
- Persons who are at high risk for influenza and its complications because of underlying medical conditions and who are receiving regular medical care for conditions such as chronic pulmonary and cardiac diseases, chronic renal diseases, diabetes mellitus and similar metabolic disorders and individuals who are immunosuppressed
- Residents of old age homes, chronic care rehabilitation institutions; 
- Children on long-term aspirin therapy
- Medical and nursing staff responsible for the care of high risk cases;1
- Adults and children who are family contacts of high risk cases;1
- All persons over the age of 65
- Any person wishing to protect themselves from the risk of contracting influenza, especially in industrial settings, where large scale absenteeism could cause significant economic losses

• IM/SC: 0.5ml

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Method of administration

To be given by intramuscular or deep subcutaneous injection after allowing the vaccine to reach room temperature. Shake before use. Inspect visually prior to administration. In the absence of compatibility studies, inactivated influenza vaccine must not be mixed with other medicines

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Instructions for use

- Disinfect the injection area and allow to dry completely
- Remove the needle guard
- Keep the syringe in an upright position and expel air by moving the plunger gently upward
- The syringe is now ready for use

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DO NOT administer intravascularly

Paed. forms avail. in South Africa and covered in this monograph: inj

South African registered indications and dosages

Prophylaxis of influenza, particularly indicated in:
- Persons who are at high risk for influenza and its complications because of underlying medical conditions and who are receiving regular medical care for conditions such as chronic pulmonary and cardiac diseases, chronic renal diseases, diabetes mellitus and similar metabolic disorders and individuals who are immunosuppressed
- Children on long-term aspirin therapy
- Children who are family contacts of high risk cases

Younger than 6 months

• Not established for use

Between 6 months to 3 years

• IM/SC: 0.25ml

Older than 3 years

• See adult dosage

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Method of administration

To be given by intramuscular or deep subcutaneous injection after allowing the vaccine to reach room temperature. Shake before use. Inspect visually prior to administration. In the absence of compatibility studies, inactivated influenza vaccine must not be mixed with other medicines

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Instructions for use

For the administration of a 0.25ml dose from a single dose 0.5ml syringe (for paediatric use only):
- Push the front side of the plunger exactly to the edge of the mark so that half of the volume is eliminated
- A volume of 0.25ml of the vaccine remains in the syringe, suitable for administration

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DO NOT administer intravascularly

Pregnancy

South African recommendations

• Safe; no evidence of risk
• Inactivated influenza vaccine can be used in all stages of pregnancy. Larger datasets on safety are available for the second and third trimester, compared with the first trimester; however, data from worldwide use of influenza vaccine do not indicate any adverse foetal and maternal outcomes attributable to the vaccine

Breastfeeding

South African recommendations

• Compatible
• Inactivated influenza vaccine may be used during breastfeeding

Fertility

South African recommendations

• No fertility data is available

South African recommendations

• Caution; no dose adjustment recommended
  Indicated in chronic renal disease

South African recommendations

• Caution; no information available

South African recommendations

• Caution; no information available

Nervous System Disorders

Common

• Headache

Post-marketing surveilance

• Neuralgia
• Paraesthesia
• Febrile convulsions
• Neurological disorders
  - Encephalomyelitis
  - Neuritis
  - Guillain Barré syndrome

Skin and Subcutaneous Tissue Disorders

Common

• Sweating

Post-marketing surveilance

• Generalised skin reaction
  - Pruritus
  - Urticaria
  - Non-specific rash

Musculoskeletal Disorders

Common

• Myalgia
• Arthralgia

General Disorders and Administration Site Conditions

Common

• Fever
• Malaise
• Shivering
• Fatigue
• Local reactions
  - Redness
  - Swelling
  - Pain
  - Ecchymosis
  - Induration

Blood and Lymphatic System Disorder

Post-marketing surveilance

• Transient thrombocytopenia
• Transient lymphadenopathy

Immune System Disorders

Post-marketing surveilance

• Allergic reactions
  - Shock
  - Angioedema

Vascular Disorders

Post-marketing surveilance

• Vasculitis (with transient renal involvement)

• Immunosuppressants

Other interactions

• Interference with serological testing (See additional prescribing points)

None routine

Interference with serological testing

• Following influenza vaccination, false-positive results in serology tests using the enzyme-linked-immunosorbent assay (ELISA) method to detect antibodies against human immunodeficiency virus type 1 (HIV1), hepatitis C and especially human T-lymphotropic virus type 1 (HTLV1) have been observed
• The Western Blot technique disproves the false-positive ELISA test results. The transient false-positive reactions could be due to the immunoglobulin M (IgM) response by the vaccine

Coadministration with other vaccines

• The inactivated influenza vaccine may be given at the same time as other vaccines. Immunisation should be carried out on separate limbs
• It should be noted that the adverse reactions may be intensified
• The inactivated influenza vaccine must not be mixed with other medicines

The purified haemagglutinin and neuraminidase antigens contained in the inactivated influenza vaccine produce a protective antibody level against influenza in a high percentage of vaccines. Seroprotection is generally obtained within 2 to 3 weeks. The duration of post-vaccinal immunity to homologous strains or to strains closely related to the vaccine strains varies but is usually 6-12 months. Inactivated influenza vaccine will only offer protection against the strains of the virus which are mentioned on the label.

The inactivated influenza vaccine is an aqueous suspension containing the purified haemagglutinin and neuraminidase antigens prepared from influenza virus strains selected on the basis of current World Health Organisation recommendations.

The strains of influenza used in the formulation are valid for 2026 only and comply with the WHO recommendations for the Southern hemisphere for 2026. It is likely that different antigenic variants will be recommended for 2027.

The inactivated influenza virus vaccine conists of the following strains:

A/Missouri/11/2025 (H1N1)pdm09-like strain (A/Switzerland/6849/2025, IVR-278)
A/Singapore/GP20238/2024 (H3N2)-like strain (A/Singapore/GP20238/2024, IVR-277)
B/Austria/1359417/2021-like strain (B/Austria/1359417/2021, BVR-26)

Injection 0.5ml

• Influvac Subunit (Abbott) originator
• Vaxigrip adult (Sanofi)
• Fluarix (GSK) originator (Discontinued: 01/01/2014)

Injection 0.25ml

• Vaxigrip Paed (Sanofi) originator