1. I Introduction to influenza
Department of Health 2015 Vaccination Campaign Training workshop
Presentation developed by the National Institute for Communicable Diseases
( Center for Respiratory Diseases and Meningitis and Division of Public Health Surveillance and Response )
Last updated: 06/ 02/ 2015

2. What is influenza? Runny nose Blocked nose Sore throat
This is NOT necessarily influenza
Many other viruses cause respiratory illness

3. Typical symptoms of flu
Sudden onset of
Fever
Chills
Cough
Headache
Muscle and joint pain
Sore throat and runny nose
Sometimes vomiting and diarrhoea

4. Severe disease
>50% of hospitalised patients have underlying medical conditions
Groups at increased risk
Pregnant women
Very young
Elderly
Immunocompromised and HIV infected
Underlying medical conditions, such as heart or lung disease or diabetes
Big contributor to mortality world-wide – 250,000 to 500,000 deaths every year.

5. Severe disease complications
Pulmonary
Pneumonia (primary influenza, secondary bacterial, and mixed) and bronchitis
Exacerbation of asthma, chronic obstructive pulmonary disease (COPD), or other underlying lung disease
Non-pulmonary
Cardiac complications (myocarditis)
Encephalopathy
Liver and central nervous system (Reye’s Syndrome)
Peripheral nervous system (Guillain-Barré syndrome)

6. What causes influenza? A virus transmitted from person-to-person by
Direct transmission: coughing and sneezing (droplet) mucus directly into the eyes, nose or mouth of another person
Airborne transmission: inhalation of aerosols produced by coughing and sneezing.
Fomites: Contaminated surfaces or hands: Hand-to-eye, -nose, -mouth
Three types: A, B and C
A and B cause much more severe disease than C

7. What causes influenza? Enveloped virus 100nm
Genome composed of 8 RNA strands
The predominant surface protein is the haemagglutinin protein (HA)
Responsible for binding to host cells and inducing neutralizing antibodies
Neuraminidase protein (NA):
Help the virus to be released from the host cell.
Body mounts immune response against HA and NA

8. Influenza virus- Antigenic Drift
HA and NA accumulate mutations
Immune response no longer protects fully
Leads to sporadic outbreaks, limited epidemics, and seasonal influenza activity

9. Influenza virus-Antigenic Shift
“New” HA or NA proteins
Pre-existing antibodies do not protect
May lead to pandemics

10. Where do the “new” HA and NA come from?
Influenza Virus
Where do the “new” HA and NA come from?
13 types of HA and 9 types of NA, circulating in domestic and wild birds, pigs, humans and other animals

11. History of Influenza pandemics
Name
Date
Deaths
CFR%
Subtype
Asiatic (Russian flu)
1 million
0.15%
H3N2
1918 flu pandemic
million 2%
H1N1
Asian flu
million
0.13%
H2N2
Hong Kong flu
0.75 – 1 million
<0.1%
2009 flu pandemic
>18,000
0.03%

12. Influenza strains detected 1984 - 2014
Courtesy of the NICD’s Viral Watch Surveillance Programme

13. Influenza seasons 1984-2014 Mean onset: Mean peak: Mean duration:
Week 22(1st week of June)
Range 17-28
2014
2013
2012
2011
2010
2009
2008
2007
2006
Mean peak:
Week 27(2nd week of July)
Range 20-32
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
Mean duration:
12 weeks
Range 7- 25
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
1985
1984
Courtesy of the NICD’s Viral Watch Surveillance Programme

14. Virologic Surveillance in South Africa, from 2009 H1N1 pandemic to present

15. Positive samples by influenza types and subtypes, South Africa 2015 ?

16. Influenza vaccines
Each year, NICD sends data and strains to the World Health Organization (WHO). Together with info from other countries, WHO predicts the specific virus strains that will be circulating in the next year
Formulation  pharmaceutical companies produce that vaccine (±6months)
Due to high mutation rate, people need to be re-vaccinated each year
Note: it is possible to still get influenza if vaccinated
Not all strains covered (max 3 specific strains in vaccine)
Vaccine takes 2 weeks to become effective. If infected during that time, you can still get flu

17. Recommended Vaccine Formulations for southern hemisphere, 2015
Trivalent vaccine
an A/California/7/2009 (H1N1)pdm09-like virus
an A/Switzerland / /2013(H3N2)-like virusa;
a B/Phuket/3073/2013-like virus
Vaccines should contain 15μg of each haemagglutinin antigen in each 0.5ml dose
Protection derived from influenza vaccination lasts about 6 months
a A/South Australia/55/2014, A/Norway/466/2014 and A/Stockholm/6/2014 are A/Switzerland/ /2013-like viruses

18. Thank you!
Presentation developed by the Division of Public Health Surveillance and Response and Center for Respiratory Diseases and Meningitis, NICD-NHLS 18