Quick Reference Guide - Influenza

Categories of influenza 

Uncomplicated influenza: ILI (Influenza-like illness) may present with fever, cough, sore throat, coryza, headache, malaise, myalgia, arthralgia and sometimes gastrointestinal symptoms, but without any features of complicated influenza.

Complicated influenza: Influenza requiring hospital admission and/or with symptoms and signs of lower respiratory tract infection (hypoxaemia, dyspnoea, tachypnoea, lower chest wall indrawing and inability to feed), central nervous system involvement and/or a significant exacerbation of an underlying medical condition. Influenza vaccination is strongly recommended as co-circulation with SARS-CoV-2 is very likely. Preventing severe influenza will decrease the burden on the health care system.

Risk groups for severe/complicated influenza disease 

• Pregnant women (including the post-partum period)
• HIV–infected individuals
• Individuals with tuberculosis
• Persons of any age with chronic diseases:
  • Pulmonary diseases (e.g. asthma, COPD)
  • Immunosuppression (e.g. persons on immunosuppressive medication, malignancy)
  • Cardiac diseases (e.g. congestive cardiac failure), except for hypertension
  • Metabolic disorders (e.g. diabetes mellitus)
  • Renal disease
  • Hepatic disease
  • Neurologic and neurodevelopmental conditions
  • Haemoglobinopathies (e.g. sickle cell disease)
• Persons aged ≥65 years
• Persons ≤18 years receiving chronic aspirin therapy
• Persons who are morbidly obese (i.e. BMI ≥40)
• Young children (particularly <2 years of age)

Treatment of influenza 

Neuraminidase inhibitors (oseltamivir or zanamivir) recommended for the treatment of any patient with suspected or confirmed influenza who:

• has complicated or severe illness (including all hospitalised patients)
• is at higher risk for influenza complications

Treatment should be started early, ideally within 48 hours of symptom onset.

Groups targeted for Department of Health 2021 influenza vaccination campaign , in order of priority. This applies to public and privately funded vaccine. 

• Healthcare workers
• Individuals aged ≥65 years
• Individuals with cardiovascular disease (including chronic heart disease, hypertension, stroke and diabetes), chronic lung disease (including asthma and chronic obstructive pulmonary disease) and individuals living with HIV and AIDS
• Pregnant women

Recommended inactivated influenza vaccine (IIV) formulation for 2021 

• an A/Victoria/2570/2019 (H1N1)pdm09-like virus;
• an A/Hong Kong/2671/2019 (H3N2)-like virus;
• a B/Washington/02/2019-like (B/Victoria lineage) virus; and
• a B/Phuket/3073/2013-like (B/Yamagata lineage) virus*

*included in the quadrivalent vaccine, is available in private sector and limited doses in public sector.

Dosage of influenza vaccine 

• ≥ 9 years 0.5ml IMI single dose (TIV/QIV)
• 3 years to 8 years-0.5ml IMI 1 or 2 doses (TIV/QIV)*
• 6 months to 2 years-0.25ml IMI 1 or 2 doses (TIV)*
• 6 months to 2 years-0.5ml IMI 1 or 2 doses (QIV)*

*2 doses should be administered ≥ 1 month apart during 1st year of vaccination, thereafter one dose.

IMI-intra-muscular injection, QIV-quadrivalent influenza vaccine, TIV-trivalent influenza vaccine

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Additional questions from health professionals can be directed to: National institute for Communicable Diseases (NICD)  Hot line: +27 082 883 9920; for Laboratory support: NICD, Centre for Respiratory Diseases and Meningitis: 011 386 6390 / 011 386 6392

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Influenza: NICD recommendations for the diagnosis, management, prevention and public health response, National institute of communicable diseases, 2021