Transcript 17 - Swine Flu (Jan 2010).ppt

Novel H1N1 (Swine)
Epidemiology & Control
Ahmed Mandil
Prof of Epidemiology
Dept of Family & Community Medicine
College of Medicine, King Saud University
HEADLINES
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Influenza Virus
Definitions
Introduction
Spread/Transmission
Timeline/Facts
Response
Case-Definitions
Treatment
Other Protective Measures
Conclusion &
Recommendations
Virus
• RNA, enveloped
• Viral family: Orthomyxoviridae
• Size:
80-200nm or .08 – 0.12 μm
(micron) in diameter
• Three types
• A, B, C
• Surface antigens
• H (haemaglutinin)
• N (neuraminidase)
Credit: L. Stammard, 1995
Definitions
General
• Epidemic – a located cluster of cases
• Pandemic – worldwide epidemic
• Antigenic drift
– Changes in proteins by genetic point mutation & selection
– Ongoing and basis for change in vaccine each year
• Antigenic shift
– Changes in proteins through genetic reassortment
– Produces different viruses not covered by annual vaccine
Timeline of Emergence
Influenza A Viruses in Humans
Reassorted Influenza virus
(Swine Flu)
1976 Swine Flu
Outbreak, Ft.
Dix
H1
Avian
Influenza
H9 H7
H5
H5
H1
H3
H2
H1
1918
1957
1968
1977
Spanish
Influenza
H1N1
Asian
Influenza
H2N2
Hong
Kong
Influenza
H3N2
Russian
Influenza
1997
2003
1998/9
2009
Lessons Learned form
Past Pandemics
•
First outbreaks March 1918 in Europe, USA
– Highly contagious, but not deadly
– Virus traveled between Europe/USA on troop
ships
– Land, sea travel to Africa, Asia
– Warning signal was missed
•
August, 1918 simultaneous explosive
outbreaks in in France, Sierra Leone, USA
– 10-fold increase in death rate
– Highest death rate ages 15-35 years
•
Cytokine Storm?
– Deaths from primary viral pneumonia, secondary
bacterial pneumonia
– Deaths within 48 hours of illness
– Coincident severe disease in pigs
•
20-40 million killed in less than 1 year
– World War I –8.3 million military deaths over 4
years
•
25-35% of the world infected
Lessons Learned form
Past Pandemics
•
Pandemics are unpredictable
–
•
•
•
Mortality, severity of illness, pattern of spread
A sudden, sharp increase in the need for medical care
will always occur
Capacity to cause severe disease in nontraditional
groups is a major determinant of pandemic impact
Epidemiology reveals waves of infection
–
–
Ages/areas not initially infected likely vulnerable in future
waves
Subsequent waves may be more severe
•
•
•
1918- virus mutated into more virulent form
1957 schoolchildren spread initial wave, elderly died in
second wave
Public health interventions delay, but do not stop
pandemic spread
–
Quarantine, travel restriction show little effect
•
•
–
–
Does not change population susceptibility
Delay spread in Australia— later milder strain causes
infection there
Temporary banning of public gatherings, closing schools
potentially effective in case of severe disease and high
mortality
Delaying spread is desirable
•
Fewer people ill at one time improve capacity to cope with
sharp increase in need for medical care
Swine Influenza A(H1N1)
Introduction
• Swine Influenza (swine flu) is a respiratory
disease of pigs caused by type A influenza
that regularly cause outbreaks of influenza
among pigs
• Most commonly, human cases of swine flu
happen in people who are around pigs
• Swine flu viruses do not normally infect
humans, however, human infections with
swine flu do occur, and cases of human-tohuman spread of swine flu viruses have
been documented
Swine Influenza A(H1N1)
Transmission to Humans
• Through contact with infected pigs or
environments contaminated with
swine flu viruses
• Through contact with a person with
swine flu
• Human-to-human spread of swine flu
has been documented also and is
thought to occur in the same way as
seasonal flu, through coughing or
sneezing of infected people
Swine Influenza A(H1N1)
Transmission Through Species
Human Virus
Avian Virus
Avian/Human
Reassorted Virus
Swine Virus
Reassortment in Pigs
Swine Influenza A(H1N1) Facts
• Virus described as a new
subtype of A/H1N1 not
previously detected in swine or
humans
• CDC determines that this virus
is contagious and is spreading
from human to human
• The virus contains gene
segments from 4 different
influenza types:
– North American swine
– North American avian
– North American human and
– Eurasian swine
Swine Influenza A(H1N1)
Global Response
•
The WHO raises the alert level to Phase 6
– WHO’s alert system was revised after Avian influenza began to spread in 2004 – Alert Level raised to Phase 3
– In Late April 2009 WHO announced the emergence of a novel influenza A virus
– April 27, 2009: Alert Level raised to Phase 4
– April 29, 2009: Alert Level raised to Phase 5
– June 11, 2008: Alert Level raised to Phase 6
Source: WHO
Swine Influenza A(H1N1)
Status Update
GLOBALLY: March 1-December 23
• At least 11,516 Deaths
–
–
–
–
–
–
Africa Region (AFRO):
Americas Region (AMRO):
Eastern Mediterranean Region (EMRO):
Europe Region (EURO) :
South-East Asia Region (SEARO):
Western Pacific Region (WPRO) :
109
6,670
663
2,045
990
1,039
ECDC reported a total of 12,776 deaths –
December 28, 2009
Source: WHO
Swine Influenza A(H1N1)
CDC Estimates from April-November 14, 2009, By Age Group
2009 H1N1
Cases
0-17 years
18-64 years
65 years and older
Cases Total
Hospitalizations
0-17 years
18-64 years
65 years and older
Hospitalizations Total
Deaths
0-17 years
18-64 years
65 years and older
Deaths Total
Mid-Level Range*
Estimated Range *
~16 million
~27 million
~4 million
~47 million
~12 million to ~23 million
~19 million to ~38 million
~3 million to ~6 million
~34 million to ~67 million
~71,000
~121,000
~21,000
~213,000
~51,000 to ~101,000
~87,000 to ~172,000
~15,000 to ~29,000
~154,000 to ~303,000
~1,090
~7,450
~1,280
~9,820
~790 to ~1,550
~5,360 to ~10,570
~920 to ~1,810
~7,070 to ~13,930
Source: CDC. http://www.cdc.gov/h1niflu/surveillanceqa.htm
Pandemic (H1N1) 2009 in the EMR as of 6 November, 2009
Country
22/22 countries affected
Regular reports from 17
countries: 26,400 confirmed
cases and 150 deaths.
Localized to moderate
geographical distribution.
Increasing trend in most
of the countries
Low to moderate intensity
Low to moderate impact on
the health system
•
Cumulative number
Cumulative
of confirmed cases
number of
Trend
deaths
Kuwait
UAE
Bahrain
6, 640
79
793
17
0
6
Increasing
NA
NA
Lebanon
Egypt
Saudi Arabia
Palestine
Morocco
Jordan
Qatar
Yemen
Oman
761
1, 592
4, 119
777
484
2, 050
23
629
3, 329
2
5
28
1
0
3
1
17
25
NA
Increasing
NA
Increasing
Increasing
Increasing
NA
Increasing
Increasing
Iran
Tunisia
Iraq
Libya
Syria
Afghanistan
Sudan
Pakistan
Djibouti
Somalia
1, 638
1, 285
1, 080
21
160
772
7
5
9
2
22
0
7
0
6
10
0
0
0
0
Increasing
Increasing
Increasing
Unchanged
Increasing
Increasing
Unchanged
Unchanged
Unchanged
Unchanged
Total
26,400
150
Pandemic H1N1 2009 in the EMR as of 6 November, 2009
Proportion of total cases, consultations, hospitalisations or de
aths
The Epidemic Curve
Initiation
Acceleration
Peak
Decline
20%
15%
10%
5%
0%
1
2
3
4
5
6
Week
7
8
9
10
11
12
Single-wave profile showing proportion of new clinical cases, consultations, hospitalisations or deaths by week. Based on London, second wave 1918.
Aims of community reduction of influenza
transmission — mitigation
Delay and flatten epidemic peak.
Reduce peak burden on healthcare system and threat.
Somewhat reduce total number of cases.
Buy a little time.
No intervention
Daily
cases
With interventions
Days since first case
400
350
300
250
200
415
450
27
6
15
Yemen
United Arab Emirates
Turkey
Tunisia
Syrian Arab Republic
Saudi Arabia
Qatar
Kuwait
Algeria
Bahrain
Egypt
Islamic Republic of Iran
Iraq
Israel
Jordan
Lebanon
Libya
Moracco
Oman
0
30
Occupied Palestinian Territory
8
23
1
5
27
7
16
50
40
42
50
71
100
110
97
109
150
147
Confirmed Deaths
Swine Influenza A(H1N1)
Mediterranean & Middle East Confirmed Deaths
As of December 28, 2009
n=1,246
Countries
Source: ECDC
Global Distribution of Reported Laboratory Confirmed Cases
& Deaths of Swine Influenza A(H1N1), December 23, 2009
Source: WHO
Geographic Spread of Influenza Activity
Based Upon Country Reporting,
Week 50, 2009 (07-23 December)
Source: WHO
Impact on Healthcare Services Based Upon Degree of Disruption,
As a Result of Acute Respiratory Diseases
Week 50, 2009 (07-13 December)
Source: WHO
Number of Specimens Positive for
Influenza Sub-Type
Source: CDC
Laboratory-Confirmed Cases & Deaths of New Influenza
A(H1N1) by WHO Regions, September 20, 2009
At least 318,925 Cases & Over 3917 Deaths
Overall Case-Fatality Rate (CFR) in Confirmed ~ 1.2%
CFR = 2.5%
No. Confirmed Cases & Deaths
140000
130448
120000
CFR = 0.4%
100000
85299
80000
CFR = 0.3%
53000
60000
40000
CFR = 0.5%
20000
CFR = 1.1%
30293
CFR = 0.6%
11621
8264
340
362
Western Pacific
Region (WPRO)
154
South-East Asia
Region
(SEARO)
Americas
Region (AMRO)
Africa Region
(AFRO)
72
Europe Region
(EURO)
2948
Eastern
Mediterranean
Region (EMRO)
41
0
WHO Region
*Given that countries are no longer required to test and report individual cases, the number of cases reported actually understates the
real number of cases.
Source: WHO
Swine Influenza A(H1N1)
Guidelines for General Population
• Covering nose and mouth with a
tissue when coughing or sneezing
– Dispose the tissue in the trash after
use.
• Handwashing with soap and water
– Especially after coughing or sneezing.
• Cleaning hands with alcohol-based
hand cleaners
• Avoiding close contact with sick
people
• Avoiding touching eyes, nose or
mouth with unwashed hands
• If sick with influenza, staying home
from work or school and limit
contact with others to keep from
infecting them
Comparison of Available Influenza Diagnostic Tests1
Influenza Diagnostic
Tests
Method
3
Availability
Typical
2
Processing Time
Sensitivity for
2009 H1N1
influenza
Distinguishes 2009 H1N1 influenza
from other influenza A
viruses?
Rapid influenza diagnostic
4
tests (RIDT)
Antigen
dete
ction
Wide
0.5 hour
10 – 70%
No
Direct and indirect
Immunofluorescence
5
assays (DFA and IFA)
Antigen
dete
ction
Wide
2 – 4 hours
47–93%
No
Viral isolation in tissue cell
culture
Virus
isola
tion
Limited
2 -10 days
-
Nucleic acid amplification
tests
7
(including rRT-PCR)
RNA
dete
ction
Limited
48 – 96 hours
[6-8 hours to
perform test]
86 – 100%
8
Yes
6
Yes
Source: CDC
Swine Influenza A(H1N1)
Antiviral Protection
•
There are two flu antiviral drugs recommended
– Oseltamivir or Zanamivir
•
Use of anti-virals can make illness milder and recovery faster
•
They may also prevent serious flu complications
•
For treatment, antiviral drugs work best if started soon after getting sick (within
2 days of symptoms)
•
Warning! Do NOT give aspirin (acetylsalicylic acid) or aspirin-containing
products (e.g. bismuth subsalicylate – Pepto Bismol) to children or teenagers
(up to 18 years old) who are confirmed or suspected ill case of swine
influenza A (H1N1) virus infection; this can cause a rare but serious illness
called Reye’s syndrome. For relief of fever, other anti-pyretic medications are
recommended such as acetaminophen or non steroidal anti-inflammatory
drugs.
•
Treatment is recommended for:
– All hospitalized patients with confirmed, probable or suspected novel influenza
(H1N1).
– Patients who are at higher risk for seasonal influenza complications
– If patient is not in a high-risk group or is not hospitalized, healthcare providers
should use clinical judgment to guide treatment decisions
Source: CDC
Swine Influenza A(H1N1)
Antiviral Protection
•
Antiviral Chemoprophylaxis for Treatment:
– Post-exposure: Duration chemoprophylaxis is 10 days after the last known
exposure to novel (H1N1) influenza and may be considered in the following:
• Close contacts of cases (confirmed, probable, or suspected)
• Health care personnel, public health workers, or first responders who have had a
recognized, unprotected close contact exposure to a person (confirmed, probable, or
suspected) during that person’s infectious period.
– Pre-exposure: Antivirals should only be used in limited circumstances, and in
consultation with local medical or public health authorities.
•
Antiviral Use for Control of Novel H1N1 Influenza Outbreaks
– A cornerstone for the control of seasonal influenza outbreaks in nursing homes and
other long term care facilities.
– If outbreaks were to occur, it is recommended that ill patients be treated with
oseltamivir or zanamivir and that chemoprophylaxis with either oseltamivir or
zanamivir be started as early as possible to reduce the spread of the virus as is
recommended for seasonal influenza outbreaks in such settings.
•
Children Under 1 Year of Age
– Oseltamivir is not licensed for use in children less than 1 year of age. Because
infants experience high rates of morbidity and mortality from influenza, infants with
novel (H1N1) influenza virus infections may benefit from treatment using
oseltamivir.
Source: CDC
Swine Influenza A(H1N1)
Antiviral Protection
Oseltamivir (Tamiflu)
Treatment
Prophylaxis
Zanamivir (Relenza)
Treatment
Prophylaxis
Adults
75 mg capsule twice
per day for 5 days
75 mg capsule once
per day
Two 5 mg inhalations
(10 mg total) twice per
day
Two 5 mg inhalations
(10 mg total) once per
day
Children
15 kg or less: 60 mg
per day divided into 2
doses
30 mg once per day
Two 5 mg inhalations
(10 mg total) twice per
day (age, 7 years or
older)
Two 5 mg inhalations
(10 mg total) once per
day (age, 5 years or
older)
15–23 kg: 90 mg per
day divided into 2
doses
45 mg once per day
24–40 kg: 120 mg per
day divided into 2
doses
60 mg once per day
>40 kg: 150 mg per
day divided into 2
doses
75 mg once per day
Dosing recommendations for antiviral treatment of children younger than 1 year using oseltamivir. Recommended treatment dose for 5
days. <3 months: 12 mg twice daily; 3-5 months: 20 mg twice daily; 6-11 months: 25 mg twice daily
Dosing recommendations for antiviral chemoprophylaxis of children younger than 1 year using oseltamivir. Recommended prophylaxis
dose for 10 days. <3 months: Not recommended unless situation judged critical due to limited data on use in this age group; 3-5 months:
20 mg once daily; 6-11 months: 25 mg once daily
Source: CDC
Swine Influenza A(H1N1)
Vaccine Protection
• Novel H1N1 vaccine available for since Mid-September
• Seventh Harvard Pandemic Survey
– 38% of Children in the US immunized
– 50% Adults do not intend to be immunized
– 35% of parents do not intend to get their children immunized
• Novel H1N1 vaccine is not intended to replace the
seasonal flu vaccine – it is intended to be used along-side
seasonal flu vaccine
• Vaccines:
– Inactivated influenza virus vaccines
• CSL Ltd. of Australia
• Novartis Vaccines of Switzerland
• Sanofi Pasteur of France
–
800,000 pre-filled syringes were recalled are for young children, ages 6 months to 3
years in the US
• GlaxoSmithKline (GSK) of UK
• Sinovac Biotech of China
– Live-attenuated virus vaccine
• MedImmune LLC of US (nasal-spray)
– 4.5 million doses recalled due to decreased potency in the US
Swine Influenza A(H1N1)
Vaccine Protection
•
CDC’s Advisory Committee on Immunization Practices (ACIP) recommends the
following groups to receive the novel H1N1 influenza vaccine:
–
Pregnant women because they are at higher risk of complications and can potentially provide
protection to infants who cannot be vaccinated;
–
Household contacts and caregivers for children younger than 6 months of age because younger
infants are at higher risk of influenza-related complications and cannot be vaccinated.
Vaccination of those in close contact with infants less than 6 months old might help protect
infants by “cocooning” them from the virus;
–
Healthcare and emergency medical services personnel because infections among healthcare
workers have been reported and this can be a potential source of infection for vulnerable
patients. Also, increased absenteeism in this population could reduce healthcare system
capacity;
–
All people from 6 months through 24 years of age
–
Children from 6 months through 18 years of age because we have seen many cases of novel
H1N1 influenza in children and they are in close contact with each other in school and day care
settings, which increases the likelihood of disease spread, and
–
Young adults 19 through 24 years of age because we have seen many cases of novel H1N1
influenza in these healthy young adults and they often live, work, and study in close proximity,
and they are a frequently mobile population; and,
–
Persons aged 25 through 64 years who have health conditions associated with higher risk of
medical complications from influenza.
Source: CDC
Swine Influenza A(H1N1):
Setting
Face Mask and Respirator Protection
Persons not at increased risk of severe
illness from influenza
(Non-high risk persons)
Persons at increased risk of severe illness from
influenza
(High-Risk Persons)
Community
No 2009 H1N1 in community
Facemask/respirator not recommended
Facemask/respirator not recommended
2009 H1N1 in community: not crowded setting
Facemask/respirator not recommended
Facemask/respirator not recommended
2009 H1N1 in community: crowded setting
Facemask/respirator not recommended
Avoid setting. If unavoidable, consider
facemask or respirator
Caregiver to person with influenza-like illness
Facemask/respirator not recommended
Avoid being caregiver. If unavoidable, use
facemask or respirator
Other household members in home
Facemask/respirator not recommended
Facemask/respirator not recommended
No 2009 H1N1 in community
Facemask/respirator not recommended
Facemask/respirator not recommended
2009 H1N1 in community
Facemask/respirator not recommended
but could be considered under certain
circumstances
Facemask/respirator not recommended but
could be considered under certain
circumstances
Respirator
Consider temporary reassignment. Respirator
Home
Occupational (non-health care)
Occupational (health care)
Caring for persons with known, probable or
suspected 2009 H1N1 or influenza-like illness
Source: CDC
Swine Influenza A(H1N1)
Other Protective Measures
Defining Quarantine vs. Isolation vs. Social-Distancing
– Isolation: Refers only to the sequestration of symptomatic
patents either in the home or hospital so that they will not infect
others
– Quarantine: Defined as the separation from circulation in the
community of asymptomatic persons that may have been
exposed to infection
– Social-Distancing: Has been used to refer to a range of nonquarantine measures that might serve to reduce contact between
persons, such as, closing of schools or prohibiting large
gatherings
Source: CDC
Swine Influenza A(H1N1)
Other Protective Measures
Personnel Engaged in Aerosol Generating Activities
• CDC Interim recommendations:
– Personnel engaged in aerosol generating activities (e.g., collection of
clinical specimens, endotracheal intubation, nebulizer treatment,
bronchoscopy, and resuscitation involving emergency intubation or
cardiac pulmonary resuscitation) for suspected or confirmed swine
influenza A (H1N1) cases should wear a fit-tested disposable N95
respirator
– Pending clarification of transmission patterns for this virus, personnel
providing direct patient care for suspected or confirmed swine influenza
A (H1N1) cases should wear a fit-tested disposable N95 respirator when
entering the patient room
– Respirator use should be in the context of a complete respiratory
protection program in accordance with Occupational Safety and Health
Administration (OSHA) regulations.
Source: CDC
Swine Influenza A(H1N1)
Other Protective Measures
Infection Control of Ill Persons in a Healthcare Setting
• Patients with suspected or confirmed case-status should be placed
in a single-patient room with the door kept closed. If available, an
airborne infection isolation room (AIIR) with negative pressure air
handling with 6 to 12 air changes per hour can be used. Air can be
exhausted directly outside or be recirculated after filtration by a high
efficiency particulate air (HEPA) filter. For suctioning, bronchoscopy,
or intubation, use a procedure room with negative pressure air
handling.
• The ill person should wear a surgical mask when outside of the
patient room, and should be encouraged to wash hands frequently
and follow respiratory hygiene practices. Cups and other utensils
used by the ill person should be washed with soap and water before
use by other persons. Routine cleaning and disinfection strategies
used during influenza seasons can be applied to the environmental
management of swine influenza.
Source: CDC
Swine Influenza A(H1N1)
Other Protective Measures
Infection Control of Ill Persons in a Healthcare Setting
• Standard, Droplet and Contact precautions should be used for all
patient care activities, and maintained for 7 days after illness onset
or until symptoms have resolved. Maintain adherence to hand
hygiene by washing with soap and water or using hand sanitizer
immediately after removing gloves and other equipment and after
any contact with respiratory secretions.
• Personnel providing care to or collecting clinical specimens from
suspected or confirmed cases should wear disposable non-sterile
gloves, gowns, and eye protection (e.g., goggles) to prevent
conjunctival exposure.
Source: CDC
Summary
•
•
•
•
•
WHO raised the alert level to Phase 6 on June 11, 2009
As of December 28, 2009, worldwide more than 208 countries and overseas territories or
communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including
at least 13,000 deaths
Northern Hemisphere: Overall disease activity has recently peaked.
Central and Eastern Europe, and in parts of West, Central, and South Asia: Continued increases in influenza
activity
United States and Canada: Influenza activity continues to be geographically widespread but overall levels of
influenza-like-illness has declined substantially
–
•
Europe: Widespread and active transmission continued to be observed throughout the continent
–
•
•
•
•
Approximately 53% of hospitalized cases in Canada had an underlying medical condition
Overall pandemic influenza activity appears to have recently peaked across a majority of countries
Western and Central Asia: Virus circulation remains active throughout the region, however disease trends
remain variable
East Asia: Influenza transmission remains active but appears to be declining overall
Central and South America and the Caribbean: influenza transmission remains geographically widespread but
overall disease activity has been declining or remains unchanged in most parts, except for in Barbados and
Ecuador, were recent increases in respiratory diseases activity have been reported
Southern Hemisphere: Sporadic cases of pandemic influenza continued to be reported without evidence of
sustained community transmission.
Summary
•
In the US
–
–
–
•
In Mexico
–
–
–
•
Number of deaths being reported is rising
Vaccine
–
–
•
Majority of the cases reported in health young adults (20-29 years)
Globally
–
•
Majority of the cases reported in health young adults
70% of the deaths were reported in healthy young adults, 20-54 years
Individuals 60+ seem to be protected as the number of cases and have a lower case-fatality
compared to the rest of the population
In EU
–
•
Highest incidence of lab-confirmed cases reported among 5-24 years old
Highest hospitalization rate among 0-4 years old
Underlying health conditions confers high risk of complications and deaths
Total Adverse Events: 5.4% (0.3% fatal)
Sanofi Pasteur & MedImmune vaccine recalled due to potency issues
Anti-virals (oseltamivir and zanamivir)
–
Oseltamivir resistance reported recently in immunocompromised patents
Conclusion/Recommendations
1. Past experience with pandemics have taught us that the second wave
is worse than the first causing more deaths due to:
– Primary viral pneumonia, Acute Respiratory Distress Syndrome (ARDS),
& Secondary bacterial infections, particularly pneumonia
– Fortunately compared to the past now we have vaccines, anti-virals and
antibiotics (to treat secondary bacterial infections) & rT-PCR based rapid
diagnostic devices
– This pandemic is milder than previously predicted with a case-fatality less
than 1%
2. At present most of the deaths due to the novel H1N1 strain has been
reported from the Americas.
•
•
Disease seems to be affecting the healthy strata of the population based
upon epidemiological data
Anecdotal data suggests that the number of deaths among the pediatric
population has risen recently due to infection with the novel H1N1
•
•
Most of these deaths however have been reported in cases with underlying
medical conditions
60 years and above age group seems to show some protection against
this strain suggesting past exposure and some immunity
Conclusion/Recommendations
3.
Each locality/jurisdiction needs to
–
–
–
–
4.
Have enhanced disease and virological surveillance capabilities
Develop a plan to house large number of severely sick and provide care
if needed to deal with mildly sick at home (voluntary quarantine)
Healthcare facilities/hospitals need to focus on increasing surge capacity
and stringent infection prevention/control
General population needs to follow basic precautions
In the Northern Hemisphere influenza viral transmission traditionally
stops by the beginning of May but in pandemic years (1957) sporadic
outbreaks occurred during summer among young adults
•
This novel H1N1 strain has survived high humidity or temperature and
continued to spread during the summer months and will continue to
spread and cause infection
Conclusion/Recommendations
5.
School Closures:
–
–
–
–
6.
Burden of Disease & Mortality
•
•
7.
Preemptive school closures merely delay the spread of disease
Once schools reopen the disease transmits and spreads
Puts unbearable pressure on single-working parents and would be
devastating to the economy
Closure after identification of a large cluster would be appropriate as
absenteeism rate among students and teachers would be high enough to
justify this action
Actual burden of the disease will be higher than the regular seasonal flu
despite the availability of vaccine, antivirals and excellent public
knowledge
With the variation in reporting it is very difficult to appreciate the total
number of deaths
It is imperative to appreciate that “times-have-changed”
•
•
Though this strain has spread very quickly across the globe and seems
to be highly infectious, today we are much better prepared than 1918
There is better surveillance, communication, understanding of infection
control, vaccines, anti-virals, antibiotics and advancement in science and
resources to produce countermeasures quickly
References
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World Health Organization (WHO):
http://www.who.int/csr/disease/avian_influenza/en/
World Organization for Animal Health (OIE):
http://www.oie.int/wahid-prod/public.php?
Centers for Disease Control & Prevention (CDC):
http://www.cdc.gov/flu/avian/index.htm
Chotani R. Just-in-time, H1N1 Influenza.
Epidemiology Supercourse. December 2009.
El-Bushra H. Global and Regional Update on Human
Pandemic Influenza A H1N1 2009. Cairo:
WHO/EMRO, 2009