National Strategy for Pandemic Influenza (pdf)
Homeland Security Pandemic Influenza Preparedness, Response, and Recovery (pdf)
Vaccination Information and Flu Prevention Thoughts (pdf)
PANDEMICS
I.) Definition of Pandemic
-
-A disease or
illness which the population has no natural immunity to which spreads across a large region of the world's
population and that continues to
increase within that population.
- Three key
ingredients for a Pandemic:
• Disease agent
is new to human population: (This means that humans have no inherent
defense against the virus because the human body has never been exposed
to it before.)
• The illness caused by the agent is serious: (Obviously,
if the virus did nothing more than give you a headache and cough, nobody
would be concerned.)
• The agent spreads easily among humans: (Must become contagious
via airborne transmission into respiratory system to become a pandemic.)
-Typically occurs in 2 to 3 waves, with each wave lasting 2 to 3
months over a period of 2 years. (The fact that this battle could go on
for so long makes this particularly troublesome to businesses.)
II.)
Seasonal Flu Vs Pandemic Flu
-Seasonal Influenza
-Changes only slightly from year to year: (This is referred to as
the antigenic shift. This means the antigen layer ((outer layer)) of the
virus changes slightly from year to year to create a slightly different
virus but because the change is minimal our bodies have some built in
immunity due to exposure to related viruses in previous years.)
- Previous exposure to similar virus allows for vaccination:
(Effective vaccines cannot be made unless the actual virus or a close
relative exists. This means good vaccines are usually available every
year prior to flu season using the previous year’s virus as the base.
-Low mortality (Primarily the sick and elderly are most impacted
by seasonal flu and those seldom end in deaths.)
-Tolerable strain on health care system: (Although the cost can
be in the hundreds of millions, this is not overwhelming.)
-Global economic effects minimal: (The impact is tolerable and
does not typically create a noticeable mark on the economy.)
- Pandemic
Influenza
-New virus - No resistance and no vaccinations available:
(antigenic mutation) (Vaccines will be made based on current H5N1
strains but these will likely not be very effective. Vaccines from
actual pandemic virus cannot be made until the virus exists, which is
why good vaccines will not be available for the first wave.)
-Higher mortality: (Younger people more susceptible to dying from
pandemic virus because their immune system response is much greater. The
victim actually dies from too much fluid in the lungs brought about by a
strong immune system response. The highest mortality during the Spanish
Flu pandemic was from ages 20 to 40.)
-Overwhelms health care systems around the world: (During
Seasonal Flu hospitals may strain to handle the increase but seldom have
significant difficulties. During a Pandemic Hospitals would be
overwhelmed with critically ill and will be understaffed as many workers
would likely become ill.)
-Impacts Global Economy: Will cripple struggling economies. (2nd
and 3rd world economies will be severely damaged. Developed countries
will likely see a recession at the very least.)
III.) History of Pandemic
- 1918 - “Spanish Flu”
- Killed 675,000 Americans
- Killed 30,000,000 to 50,000,000 worldwide
- 1957 - “Asian Flu”
- Killed over 70,000 Americans
- Killed 1 to 2 million worldwide
- 1968 - “Hong Kong Flu”
- Killed 34,000 Americans
- Killed 1,000,000 worldwide
IV.) What
is the Bird Flu Virus? - Also Known as Avian Flu Virus or H5N1
- Naturally
occurring virus among wild birds: (Found in most migratory bird
populations, thus allowing the virus to spread across Asia, Europe and
Africa.)
- It has multiple genetic strains that have been in bird
populations for many years.
- Virus is spread through bird feces, secretions etc. (Body
Fluids of any kind.)
- Some strains more deadly to bird populations than others:
(Some strains cause no harm to the birds. This makes them good carriers
of the virus.)
- Some strains more readily mutate with greater human susceptibility
than others.
(H5N1 is one that mutates often. There are now at least four variations
of the H5N1 virus).
- Current strains cannot attach to upper respiratory tract like
seasonal virus:
Deep lung attachment is needed which requires sustained high level
exposures for human infection. (This is why only those people heavily
exposed to infected birds are becoming ill.)
- One strain has recently mutated and has shown the ability, in
laboratory testing, to survive in the upper respiratory tract. This is a
characteristic that is critical for human to human transmission.)
V.) Why is
H5N1 a Concern?
- Human mortality rates are currently > than 50%.- 144 of 258
confirmed cases
- Highly variable genetics: Virus mutates often and easily.
- One strain has already shown the ability to survive in the upper
respiratory tract making human to
human transmission more likely.
- Many healthy birds carry a form of the virus allowing for
greater transmission of virus globally.
- All strains have shown the ability to cross over to infect
domestic poultry, other mammals and
humans.
- Infected people are believed to show no symptoms for the first 24
to 48 hours making containment
very unlikely.
VI.) What
to Expect?
-
Appropriate mutations or “adaptations” have taken place in one
strain of the virus but proven in the laboratory only. No known cases of
human to human transmission have occurred as of 10/10/07. (That
changed in 2008).
- When common human to human transmission of the virus occurs the
global
pandemic threat level will rise to level 4. (Currently at 4)
- When transmission becomes common and wide spread within a small
region, the level will be raised to 5.
- Once it is viewed as uncontained and spreading over a large portion
of the world: it will be a Global Pandemic and the level will be
raised to 6.
- Still no way of knowing when this could occur:
- World Health Organization - “Planning is a must but fear is
unnecessary.”
VII.) What
if the Proper Mutation Occurs?
KEY VARIABLES:
(These factors will greatly affect the overall impact of the
pandemic or even if there is a pandemic.)
#1) Where will
it originate?
Containment
is key: Less developed countries may have difficulty containing due
to inability to recognize virus. (This is probably the most important
factor. If the initial outbreak is slowed or contained for some time
that will allow for better preparation globally.)
#2) How
pathogenic will it be?
Moderate virus like
1957 or Severe like 1918 or the virulence of the various H5N1 strains
varies from moderate to severe.
#3) How prepared
will the world be?
Developed countries
will likely be much better prepared with much lower infection and death
rates. African or undeveloped nations likely to see highest rates, due
to poor health care systems and dense population centers.
VIII.) Estimates of Impact in the U.S.
Moderate
Severe
Number of Sick:
90 million 90 million
Hospitalization: 865,000 to 9.9 million
ICU Care 129,000 1.5
million
Mech Ventilation: 65,000 75,000
Deaths: 209,000 1.9
million
(No Global estimates available.)
IX.)
Control and Prevention Measures
- Containment
- Travel restrictions: (Countries will impose flight restrictions
in and out of infected countries but border crossings via car will be
difficult to monitor and enforce restrictions. Local Communities will
also have recommended travel restrictions but enforcement will be nearly
impossible.)
- Screening at borders: (Again, difficult to be perfect
but countries will attempt to limit travel between countries especially
if the virus has populated neighboring country.)
- Isolation of early cases: (Will require good detection methods.
Once again, less developed areas with poor health care management will
likely not be able to isolate areas quickly enough.)
- Vaccines
- Experimental vaccines available for first wave: (These will be
made from non-pandemic H5N1 strains but may help ease the severity of
the illness in those who become infected.)
- Larger amounts of true vaccine should be available for 2nd and 3rd
waves:
(After the pandemic virus is formed production of true vaccines will
begin shortly thereafter. Their will not be enough for everyone when the
second wave arrives but health care workers and high risk individuals
should be protected. Faster vaccine production methods are now being
developed.)
- Antiviral medications - Tamiflu and Relenza are now being
stockpiled by many governments. (Goal is to stockpile enough for 25% of
U.S. population, varies in other countries.)
- Effectiveness still not known: (Likely to provide only minimal
reduction in the pandemic flu symptoms.)
- May be in short supply after 1st wave.
X.)
Methods of Control
- Transmission Intervention
- Surgical masks, gloves, N95 style respirators: (Surgical
masks will help prevent spread of particles during coughs from infected
persons. Does not protect people from inhaling particles. N95 style
respirators will best protect people from inhaling germs.)
- Isolation of the sick and those exposed to sick individuals:
(Limit contact with those you know have sick family members.)
- Frequent hand washing and hand sanitizer use (Avoid hand
contact with high risk surfaces such as door handles and drinking
fountains.)
- Cough or sneeze into your arm, not hands.
Social
Distancing
• No mass gatherings. (This will mean we have to restrict
meetings, cafeteria use etc… Communities will likely close schools and
urge caution when going to malls, churches or grocery stores. Many
businesses may close if personnel become ill.)
• No hand shaking or sharing of phones, pens etc…
• Telecommuting required when possible: (Employees who can work
from home will be encouraged to do so. The ability of the IT networks to
carry the load of remote working is still unclear.)
• Limited air travel. (Governments may limit travel)
• Follow “3 foot rule” with interpersonal communications: (This
simply means staying at least 3 feet or 1 meter from someone when you
speak with them. A study confirmed that using the 3 foot rule reduced
transmission of flu virus by over 65% in controlled areas.)