Title: Novel H1N1 (Swine) Epidemiology
1- Novel H1N1 (Swine) Epidemiology Control
- Ahmed Mandil
- Prof of Epidemiology
- Dept of Family Community Medicine
- College of Medicine, King Saud University
2HEADLINES
- Influenza Virus
- Definitions
- Introduction
- Spread/Transmission
- Timeline/Facts
- Response
- Case-Definitions
- Treatment
- Other Protective Measures
- Conclusion Recommendations
3Virus
Credit L. Stammard, 1995
4Definitions 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
5(No Transcript)
6Lessons Learned formPast 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
7Lessons Learned formPast 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
8Swine 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-to-human spread of
swine flu viruses have been documented
9Swine 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
10Swine Influenza A(H1N1) Transmission Through
Species
Reassortment in Pigs
11Swine 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
12Swine Influenza A(H1N1) Global Response
- The WHO raises the alert level to Phase 6
- WHOs 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
13Swine Influenza A(H1N1)Status Update
- GLOBALLY March 1-December 23
- At least 11,516 Deaths
- Africa Region (AFRO) 109
- Americas Region (AMRO) 6,670
- Eastern Mediterranean Region (EMRO) 663
- Europe Region (EURO) 2,045
- South-East Asia Region (SEARO) 990
- Western Pacific Region (WPRO) 1,039
ECDC reported a total of 12,776 deaths December
28, 2009
Source WHO
14Swine Influenza A(H1N1) CDC Estimates from
April-November 14, 2009, By Age Group
2009 H1N1 Mid-Level Range Estimated Range
Cases  Â
0-17 years 16 million 12 million to 23 million
18-64 years 27 million 19 million to 38 million
65 years and older 4 million 3 million to 6 million
Cases Total 47 million 34 million to 67 million
Hospitalizations  Â
0-17 years 71,000 51,000 to 101,000
18-64 years 121,000 87,000 to 172,000
65 years and older 21,000 15,000 to 29,000
Hospitalizations Total 213,000 154,000 to 303,000
Deaths  Â
0-17 years 1,090 790 to 1,550
18-64 years 7,450 5,360 to 10,570
65 years and older 1,280 920 to 1,810
Deaths Total 9,820 7,070 to 13,930
Source CDC. http//www.cdc.gov/h1niflu/surveillan
ceqa.htm
15Pandemic (H1N1) 2009 in the EMR as of 6 November,
2009
Country Cumulative number of confirmed cases Cumulative number of deaths Trend
Kuwait 6, 640 17 Increasing
UAE 79 0 NA
Bahrain 793 6 NA
Lebanon 761 2 NA
Egypt 1, 592 5 Increasing
Saudi Arabia 4, 119 28 NA
Palestine 777 1 Increasing
Morocco 484 0 Increasing
Jordan 2, 050 3 Increasing
Qatar 23 1 NA
Yemen 629 17 Increasing
Oman 3, 329 25 Increasing
Iran 1, 638 22 Increasing
Tunisia 1, 285 0 Increasing
Iraq 1, 080 7 Increasing
Libya 21 0 Unchanged
Syria 160 6 Increasing
Afghanistan 772 10 Increasing
Sudan 7 0 Unchanged
Pakistan 5 0 Unchanged
Djibouti 9 0 Unchanged
Somalia 2 0 Unchanged
Total 26,400 150
- 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
-
16Pandemic H1N1 2009 in the EMR as of 6 November,
2009
17The Epidemic Curve
Initiation
Acceleration
Peak
Decline
aths
20
15
Proportion of total cases, consultations,
hospitalisations or de
10
5
0
1
2
3
4
5
6
7
8
9
10
11
12
Week
Single-wave profile showing proportion of new
clinical cases, consultations, hospitalisations
or deaths by week. Based on London, second wave
1918.
18Aims 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
Days since first case
19Swine Influenza A(H1N1) Mediterranean Middle
East Confirmed Deaths
As of December 28, 2009
n1,246
Source ECDC
20Global Distribution of Reported Laboratory
Confirmed Cases Deaths of Swine Influenza
A(H1N1), December 23, 2009
Source WHO
21Geographic Spread of Influenza ActivityBased
Upon Country Reporting, Week 50, 2009 (07-23
December)
Source WHO
22Impact on Healthcare Services Based Upon Degree
of Disruption, As a Result of Acute Respiratory
DiseasesWeek 50, 2009 (07-13 December)
Source WHO
23Number of Specimens Positive for Influenza
Sub-Type
Source CDC
24Laboratory-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
CFR 0.4
CFR 0.3
CFR 1.1
CFR 0.5
CFR 0.6
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
25Swine 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
26Comparison of Available Influenza Diagnostic
Tests1
Influenza Diagnostic Tests Method Availability Typical Processing Time2 Sensitivity3 for 2009 H1N1 influenza Distinguishes 2009 H1N1 influenza from other influenza A viruses?
Rapid influenza diagnostic tests (RIDT)4 Antigen detection Wide 0.5 hour 10 70 No
Direct and indirect Immunofluorescence assays (DFA and IFA)5 Antigen detection Wide 2 4 hours 4793 No
Viral isolation in tissue cell culture Virus isolation Limited 2 -10 days - Yes 6
Nucleic acid amplification tests (including rRT-PCR) 7 RNA detection Limited8 Â 48 96 hours 6-8 hours to perform test 86 100 Yes
Source CDC
27Swine 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 Reyes
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
28Swine 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
persons 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
29Swine Influenza A(H1N1) Antiviral Protection
Oseltamivir (Tamiflu) Oseltamivir (Tamiflu) Zanamivir (Relenza) Zanamivir (Relenza)
Treatment Prophylaxis 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)
Children 1523 kg 90 mg per day divided into 2 doses 45 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)
Children 2440 kg 120 mg per day divided into 2 doses 60 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)
Children gt40 kg 150 mg per day divided into 2 doses 75 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)
Dosing recommendations for antiviral treatment of
children younger than 1 year using oseltamivir.
Recommended treatment dose for 5 days. lt3 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. lt3
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
30Swine 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)
31Swine Influenza A(H1N1) Vaccine Protection
- CDCs 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
32Swine Influenza A(H1N1) Face Mask and
Respirator Protection
Setting 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 Community 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
Home Home Home
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
Occupational (non-health care) Occupational (non-health care) Occupational (non-health care)
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
Occupational (health care) Occupational (health care) Occupational (health care)
Caring for persons with known, probable or suspected 2009 H1N1 or influenza-like illness Respirator Consider temporary reassignment. Respirator
Source CDC
33Swine 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 non-quarantine measures that might serve
to reduce contact between persons, such as,
closing of schools or prohibiting large gatherings
Source CDC
34Swine 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
35Swine 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. Â 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
36Swine 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
37Summary
- 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 - Approximately 53 of hospitalized cases in Canada
had an underlying medical condition - Europe Widespread and active transmission
continued to be observed throughout the continent - 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.
38Summary
- In the US
- 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 - In Mexico
- 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
- Majority of the cases reported in health young
adults (20-29 years) - Globally
- Number of deaths being reported is rising
- Vaccine
- 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
39Conclusion/Recommendations
- 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 - 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
40Conclusion/Recommendations
- Each locality/jurisdiction needs to
- 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
41Conclusion/Recommendations
- School Closures
- 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 - Burden of Disease Mortality
- 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
42References
- 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