EPIDEMIOLOGY OF PANDEMIC INFLUENZA

1. EPIDEMIOLOGY
OF PANDEMIC
INFLUENZA
(H1N1)
DR. MAHESWARI JAIKUMAR.
maheswarijaikumar2103@gmail.com

2. WHO’S ALERT ON H1N1

3. OTHER NAME
SWINE

4. DISEASE BURDEN IN INDIA

5. States of India per
confirmed cases
4000+ cases
2000+ cases
1000+ cases
500+ cases
100+ cases
1+ cases
no case confirmed

7. H1N1 (2009)
• The pandemic influenza A
(H1N1) caused by H1N1 virus
belonging to the orthomyxovirus
group.

8. SWINE FLU VIRUS

10. H1N1 is a flu virus.
When it was first
detected in 2009,
it was called
“swine flu”
because the virus
was similar to
those found in
pigs.

11. • The H1N1 virus is currently a
seasonal flu virus found in
humans.

12. • Swine flu (H1N1 and H3N2v
influenza virus) facts. Swine flu is a
respiratory disease caused by
influenza viruses that infect the
respiratory tract of pigs and result in
a barking cough, decreased
appetite, nasal secretions, and
listless behavior; the virus can be
transmitted to humans.

13. INCUBATION PERIOD
• Approximately 2-3 days, but
could extend up to 7 days.

14. TRANSMISSION

15. CASE DEFINITIONS
• SUSPECTED CASE: A suspected
case of influenza A 2009 is
defined as a person with acute
febrile respiratory illness (fever
>38 degree Celsius) with onset
within 7 days of close contact
with a person who is a
confirmed case or……

16. Cont…..
• Within 7 days of travel to areas
where there are one or more
confirmed cases, or resides in a
community where there are one
or more confirmed H1N1 cases.

17. PROBABLE CASE
• A probable case of influenza
2009 is defined as a person with
an acute febrile respiratory
illness who is positive for
influenza A, but…….
Cont….

18. Cont…..
• Unsubtypable for H1 and H3 by
influenza RT-PCR or reagents
used to detect seasonal
influenza virus infection, or…..
Cont…

19. Cont…..
• Is positive for influenza A by an
influenza rapid test or an
Influenza Immunofluoresence
Assay (IFA) and meets criteria for
a suspected case, or……
Cont…

20. Cont….
• Individual with a clinically
compatible illness who died of
an unexplained acute respiratory
illness who is considered to be
epidemiologically linked to a
probable or confirmed case.

21. CONFIRMED CASE
• A confirmed case of pandemic
influenza A 2009 virus infection is
defined a person with an acute
febrile respiratory illness with
laboratory confirmed influenza A
2009 at WHO approved laboratory
by one or more of the following
test, ……………Cont…

22. Cont…
• Real time PCR.
• Viral culture.
• Four-fold rise in influenza A virus
specific neutralizing antibodies.

24. CLINICAL FEATURES
• The clinical features range from
non febrile mild upper
respiratory illness or severe
complications including
pneumonia.

25. UNCOMPLICATED INFLUENZA
• Influenza Like Illness (ILI) include
fever, cough, sore throat,
rhinorrhea, headache, muscle
pain and malaise, but no
dysnoea.

28. • Gastro intestinal illness may also
be present such as diarrhoea and
or vomiting especially in
children.

31. SEVERE/COMPLICATED
INFLUENZA
• Presents clinical and radiological
signs of lower respiratory tract
(pneumonia, CNS involvement –
encephalopathy, encephalitis,
severe dehydration, renal failure
and septic shock,
rhabdomyolysis & myocarditis.

32. A complicated condition
also may include
• Exacerbation of underlying
chronic disease including
asthma, COPD, Hepatic Failure,
Renal Failure & other
Cardiovascular conditions. … or
any signs of progressive disease
requiring hospitalization.

34. RISK FACTORS FOR SEVERE
DISEASE include :
• Infants, young children, Pregnant
women, persons with COPD,
persons with cardiovascular
disease, persons with metabolic
disorders, children receiving
chronic aspirin therapy, persons
aged above 65 years.

35. LABORATORY DIAGNOSIS
• Reverse Transcriptase
Polymerase Chain Reaction (RT-
PCR) provides the most timely
and sensitive detection of the
infection.

36. • Clinical specimens to be
collected include, respiratory
samples. (combination of nasal
or nasopharyngeal samples,
throat swab.

37. INFECTION CONTROL
• CAN BE ACHIEVED BY,
• Strict adherence to hand hygiene
with soap and water or an
alcohol based hand sanitizer.

38. • To cover the mouth and nose
with tissue or handkerchief
when coughing or sneezing.
• If ill person have to go out for
medical treatment they should
wear a face mask to reduce the
risk of spreading the virus in the
community.

41. • Isolation (of patients) procedure
must be adhered to at least for 7
days.

42. PREVENTION
• Vaccine is available. (Live
attenuated vaccine, inactivated
unadjuvanted vaccines and vaccines
containing A/California/7/2009 like
virus, and …….. Cont…..(next slide)

43. …….(vaccines containing
A/California/7/2009) antigen
stimulated anti-HA antibodies of
similar titres against the vaccines
virus and recent pandemic A(H1N1)
viruses.

44. Cont….
• (vaccines containing
A/California/7/2009) antigen
stimulated anti-HA antibodies of
similar titres against the vaccines
virus and recent pandemic A
(H1N1) viruses.

46. INACTIVATED VACCINE
• Monovalent vaccine containing
antigen equivalent to
A/California/7/2009(H1N1) V –
like strain, 15 micrograms of
heamagglutinin per 0.5 ml dose.

47. • Inactivated vaccines contain
Thiomersal if they are supplied
in multi-dose vials (10 dose of
0.5 ml).
• It is a commonly used vaccine
preservative to prevent vaccine
contamination by bacteria
during use.

48. • The vaccine should be stored
between 2 to 8 Celsius. It should
not be frozen.
• The vaccine is administered as
single dose intramuscular
injection in the upper arm.

49. • In infants aged more than 6
months and young children thigh
is preferred site for vaccination.

50. SIDE EFFECTS
• Inactivated influenza vaccines,
administered by injection,
commonly cause local reactions
such as soreness, swelling and
redness at the injection site.
• These symptoms generally last for
two days and require no medical
attention.

51. • Rarely influenza vaccine can
cause allergic reactions such as
hives, rapid swelling of deeper
skin layers and tissues, asthma
or a severe multisystem allergic
reaction due to hypersensitivity
to certain components.

52. CONTRAINDICATIONS
• Vaccine should not be administered to :
• People who have severe allergy to
chicken egg.
• Individuals with anaphylactic reactions.
• Individuals with Guillain Barre
Syndrome.
• Children less than 6 months.

53. PREVENTION

55. PREVENTION AT
INDIVIDUAL LEVEL

56. HEALTH EDUCATION

57. SPREAD AWARENESS

59. AWARENESS

61. TREATMENT
• Symptomatic care.
• Antiviral therapy (Oseltamivir,
Zanamivir).

62. ANTI VIRAL TREATMENT
REGIMEN
• Oseltamivir is indicated for the
treatment of influenza.
• The recommended dose for
adults is 75mg twice daily for 5
days.

64. TREATMENT OF INFANT
• Oseltamivir- THE RECOMMENDED DOSE FOR
INFANTS IS AS FOLLOWS.
AGE DOSE
> 3Mo 3 mg/kg, twice daily for 5
days.
> 1 Mo to 3 Mo 2.5mg/Kg, twice daily for
5 days
0 to 1 Mo 2mg/kg, twice daily for 5
days.

65. TREATMENT OF OLDER
CHILDREN
WEIGHT DOSE
15 Kg OR Less 30 mg twice a day *5 days
15-23 Kg 45 mg twice a day *5 days
24-40 Kg 60 mg twice a day *5 days
> 40 Kg 75 mg twice day * 5 days

66. • Zanamivir is indicated for
treatment of influenza in adults
and children (>5 years).
• The recommended dose for
treatment of adults and children
from the age of 5 years is TWO
INHALATIONS (2X5 Mg)twice
daily for 5 days.

67. CHEMOPROPHYLAXIS
• Oseltamivir is the drug of choice
for prophylaxis to health care
personnel and close contacts and
suspects.
• It should be administered till 10
days after exposure.

68. RECOMMENDED DOSE-
OSELTAMIVIR
WEIGHT DOSE
< 15 Kg 30 mg OD
15-23 Kg 45 mg OD
24-40 Kg 60 mg OD
> 40 Kg 75 mg OD

70. RECOMMENDED DOSE-
OSELTAMIVIR FOR INFANTS
AGE DOSE
< 3 Mo Not recommended
unless situation is
critical
3-5 Mo 20 mg OD
6-11 Mo 25 mg OD

71. THANK YOU