# Presentation: 649874

##  An Introduction to Seasonal, Avian, and Pandemic Influenza

- Centers for Disease Control and Prevention
- June 7, 2006

## Today’s Agenda

- Understanding influenza
- Understanding the difference between seasonal influenza, avian influenza, and pandemic influenza
- Preparation and response –
- What others are doing on your behalf
- What you can do to protect yourself and others

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
Learning Objectives:
We will cover basic information about influenza, including the differences between seasonal influenza, avian influenza, and pandemic influenza.
Many governments and organizations are collaborating to prepare and respond should an influenza pandemic occur.
There are actions you and your family, friends and colleagues can take to help protect yourself and others against seasonal and pandemic influenza.

## Definition of Influenza

- A contagious disease caused by a virus
- Primarily affects the respiratory tract
- Can cause severe illness and lead to life-threatening complications
- A global infectious disease threat
- An annual public health problem

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
It is important to be clear about the definition and symptoms of influenza. Influenza is a contagious disease caused by a virus.  It primarily infects the respiratory tract (nose, throat, and lungs). The disease can cause severe illness and lead to life-threatening complications, such as pneumonia.
Influenza poses both a global infectious disease threat and an annual public health problem.

## Differences Between Seasonal, Avian and Pandemic Flu*

***Seasonal flu*** is a contagious respiratory illness caused by influenza viruses.
***Avian flu*** is caused by avian influenza viruses, which occur naturally in birds.
***Pandemic flu*** is a serious illness that spreads easily from person to person during a global outbreak, or pandemic.  Currently, there is no pandemic flu.
- *According to www.cdc.gov/flu/avian

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
Before we get ahead of ourselves, let’s first distinguish between the various types of influenza – or flu:
Seasonal flu is a contagious respiratory illness caused by influenza viruses.
Avian influenza is an infection caused by avian (bird) influenza (flu) viruses. 
Now, let’s look at pandemic influenza, which is markedly different from the seasonal influenza that circulates each year. It is very important to remember that three factors are necessary for an influenza pandemic to occur: 1) a new influenza A virus must emerge in the human population; 2) the virus must cause serious illness in humans; and 3) the virus must spread easily from person to person.  
AGAIN, TO BE A PANDEMIC, IT MUST MEET ALL THREE OF THESE CRITERIA. 

## More About Seasonal Influenza or the “Flu”

- Easily confused with other infections, such as
- Colds
- Other viral infections
- Usually self-limited to about a week of illness
- Complications can contribute to serious secondary infections and may lead to hospitalization and death

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
It is important to be clear about the definition and symptoms of influenza or “flu.” Influenza is a contagious, viral disease that primarily infects the respiratory tract (nose, throat and lungs). It is easy to mistake influenza for other infections, such as colds and other viral infections. Although seasonal influenza usually lasts only about a week for many people, it can last longer and can contribute to serious secondary infections, such as pneumonia. Complications may lead to hospitalization and death, particularly among the elderly, the young and those with certain chronic conditions.
People sometimes confuse influenza with “stomach flu” because of the word “flu” in both phrases. “Stomach flu” is actually a general term for gastroenteritis, which causes nausea and vomiting – symptoms not usually seen in typical cases of seasonal influenza. 

## Usual Symptoms of Seasonal Flu

- Fever
- Fatigue
- Body aches

- Headache
- Dry Cough
- Runny or stuffy nose

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
Usual symptoms of seasonal influenza include fever, headache, fatigue, dry cough, body aches and a runny or stuffy nose. Children also may have gastrointestinal symptoms, such as nausea, vomiting, or diarrhea.

## How Seasonal Influenza is Spread

- Primarily through respiratory droplets
-  Coughing
-  Sneezing
-  Touching respiratory droplets on self, another person, or an object, and then touching mouth, nose, eyes without washing hands

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
It is thought that the main way influenza viruses spread from person to person is be through transmission of respiratory droplets during coughing and sneezing. Close contact (about 3 feet or less) is usually necessary for this type of spread. Influenza viruses also can spread by touching respiratory droplets on yourself, others, or an object, and then touching mucous membranes, such as the mouth, nose, or eyes, without washing contaminated hands.

## Seasonal Influenza Protections

- Practice good personal hygiene
- Stay home if you are sick
- Get vaccinated
- Influenza viruses change more than other respiratory viruses
- Minor changes occur constantly (drift)
- Cumulative
- Reason why vaccine is updated each year
- Keep informed about influenza outbreaks: **www.cdc.gov/flu**

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
Protecting yourself and others against infection by seasonal influenza viruses is important to help everyone stay as healthy as possible and to reduce high rates of illness and death that occur annually because of influenza. Some basic prevention steps that you can take are 1) practice good personal hygiene, especially frequent hand washing; 2) stay home if you are sick; and 3) get vaccinated.
It is important to understand that influenza viruses change often. Minor changes, also known as “antigenic drift,” occur constantly. That is why it is so important to be vaccinated annually.  Scientists try to match the components of each year’s vaccine with predicted circulating strains by using information from domestic and global surveillance networks. 
Sometimes, more radical genetic changes, or “antigenic shift,” occur, resulting in the emergence of a new influenza A virus in the human population. 

## Impact of Seasonal Influenza

- 250,000 to 500,000 deaths globally/year
- 36,000 deaths and more than 200,000 hospitalizations/year in United States
- $37.5 billion in economic costs/year in United States related to influenza and pneumonia
- Ever-present threat of pandemic influenza

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
Seasonal influenza has a significant impact on public health impact each year, including
 250,000 to 500,000 deaths globally/year
 36,000 deaths and more than 200,000 hospitalizations/year in the United States
 $37.5 billion in economic costs related to influenza and pneumonia/year in the United States
 Ever-present threat of pandemic influenza

## Seasonal Influenza vs. Pandemic

- Seasonal outbreaks
- Caused by subtypes of influenza viruses that already circulate among people
- Pandemic outbreaks
- Caused by
- New subtypes
- Subtypes that have never circulated among people
- Subtypes that have not circulated among people for a long time

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
It is important to understand the differences between seasonal and pandemic influenza: 
Seasonal influenza outbreaks are caused by influenza virus subtypes that already circulate among people. 
In contrast, pandemic outbreaks are caused by new subtypes, by subtypes that have never circulated among people, or by subtypes that have not circulated among people for a long time.

## Influenza Viruses

- Naturally infect several animal species
- Birds and mammals, including people
- People usually infected only by human viruses
- Wild birds are main reservoir for influenza A viruses
- All known “A” subtypes circulate in wild birds
- Infect wild and domesticated birds
- Ultimate source for viruses (and virus genes) infecting other animal species

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
Influenza viruses infect a number of animal species, including birds and mammals. People are usually infected only by specific human influenza viruses – influenza A and influenza B – that circulate widely among people throughout the year. Therefore, a combination of influenza A and B viruses is included in the annual influenza vaccine. 
Influenza viruses that infect birds are called “avian influenza viruses.” These are type A influenza viruses that are genetically distinguishable from influenza viruses that usually infect people. Wild birds worldwide carry the viruses in their intestines, but usually do not get sick from them. However, avian influenza is very contagious among birds and can make some domesticated birds, including chickens, ducks, and turkeys, very sick and kill them. These viruses have demonstrated a capacity to recombine or to change in other ways that enhance their capacity to infect species other than birds, including humans. 

## Avian Influenza Viruses

**Avian Influenza Viruses**

**H1 – H16**

**H1 – H3**

**Human Influenza **
**A Viruses**

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
Of the different types of avian influenza viruses, the type known as influenza A (H5N1) virus has raised concerns worldwide.  H5N1 virus does not usually infect people, but infections with these viruses have occurred in humans. Most of these cases have resulted from people having direct or close contact with H5N1-infected poultry or H5N1-contaminated surfaces. 

So far, the spread of H5N1 virus from person to person has been very limited and has not continued beyond one person. However, because all influenza viruses have the ability to change, scientists are concerned that H5N1 virus could one day be able to infect humans and spread easily from one person to another. Because these viruses do not commonly infect humans, there is little or no immune protection against them in the human population. If H5N1 virus were to gain the capacity to spread easily from person to person, an influenza pandemic -- or worldwide outbreak of disease -- could begin. 

## Impact of Potential Pandemic

**Illness (estimated 30% attack rate):**
- Moderate 90 million
- Severe 90 million
**Hospitalization:**
- Moderate 865,000
- Severe 9,900,000
**Mechanical ventilation:**
- Moderate  65,000
- Severe  750,000
**Deaths:**
- Moderate 209,000 (comparable to 1956-58)
- Severe 1,903,000 (comparable to 1918-19)

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
Concerns about Pandemic Influenza:
Rapid global spread
Simultaneous impacts that disrupt national and community infrastructures
Increased burden on hospitals and outpatient care systems
Shortage and delays of vaccines and antiviral medications

## Current Influenza Vaccine Production Timeline: 6-9 months

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
If a pandemic strain were to appear, it would take time to develop and distribute large quantities of vaccine that could protect humans against a pandemic influenza strain. Development and distribution of vaccine for a pandemic strain of influenza cannot fully begin until the actual pandemic strain is identified. In addition, vaccine would likely not be available to most countries (resource-rich vs. resource-poor countries). As shown in this slide, even production and distribution of current, seasonal vaccine takes many months from strain selection to vaccine licensure.

## Stages of an Influenza Pandemic

- The World Health Organization defines the six stages of a pandemic:
*Interpandemic period*
- Phase 1: No new influenza virus subtypes have been detected in humans.
- Phase 2: No new influenza virus subtypes have been detected in humans.  However, a circulating animal influenza virus subtype poses a substantial risk of human disease.

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
The World Health Organization defines the six stages of a pandemic:
Interpandemic period:
Phase 1: No new influenza virus subtypes have been detected in humans. 
Phase 2: No new influenza virus subtypes have been detected in humans.  However, a circulating animal influenza virus subtype poses a substantial risk of human disease.
The distinction between phases 1 and 2 is based on the risk of human infection or disease resulting from circulating strains in animals.  The distinction is based on various factors and their relative importance according to current scientific knowledge.

## Stages of an Influenza Pandemic (continued)

*Pandemic alert period*
- Phase 3: Human infection(s) with a new subtype, but no human-to-human spread, or at most, rare instances of spread to a close contact.
- Phase 4: Small cluster(s) with limited human-to-human transmission, but spread is highly localized, suggesting that the virus is not well adapted to humans.
- Phase 5: Large cluster(s), but human-to-human spread still localized, suggesting that the virus is becoming increasingly better adapted to humans, but may not yet be fully transmissible (substantial pandemic risk).

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
Read slide...
The distinction among phases 3, 4, and 5 is based on an assessment of the risk of a pandemic.  Various factors and their relative importance, according to current scientific knowledge, may be considered.  Factors may include rate of transmission, geographic location and spread, severity of illness, presence of genes from human strains (if derived from an animal strain) and other scientific parameters.

## Stages of an Influenza Pandemic (continued)

*Pandemic period*
- Phase 6: Pandemic: increased and sustained transmission in general population.

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
Read slide...

## Currently...

- H5N1 infection is widespread among
- wild birds and domestic poultry

- Reports of H5N1-infected humans
- Limited human-to-human spread of virus

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
Currently –  
We are in World Health Organization Pandemic Alert Phase 3:
Avian influenza A(H5N1) virus is circulating among birds in many parts of the world.  
As of April 2006, H5N1 infection has been confirmed in more than 200 people; most cases have resulted from direct or close contact with sick or dead infected poultry. 
Very limited human-to-human transmission has been reported.

## Preparation and Response

- • Individuals and Families                        • Businesses • Communities                   • Faith-based Organizations                   • Health Care Providers • Governments                                       • International Organizations

## Importance of Seasonal Flu Program to Pandemic Preparedness

- Everyone has a role:
- People learn and practice basic steps to stay healthy.
- Manufacturers strengthen resources to produce and deliver influenza vaccines.
- Collaborative planning helps ensure readiness in communities, states, nationally and internationally.

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
The seasonal influenza program and preparedness for an influenza pandemic are closely linked. 
For example, learning and practicing basic health steps will be especially important during a pandemic. 
Also, as more people receive seasonal influenza vaccines, more manufacturers can develop or strengthen their systems for producing and delivering vaccine, including a vaccine specifically for an influenza pandemic when needed. Ongoing surveillance is essential for both seasonal influenza and identification of potential pandemic strains. Finally, ongoing collaborative planning among groups helps ensure readiness among all.

## What is Being Done on Your Behalf to Prepare for an Influenza Pandemic?

- U.S. Government, including Health and Human Services (HHS), CDC, the National Institutes of Health, and other federal agencies
- World Health Organization (WHO)
- Governments and other organizations around the world

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
The U.S. Government is taking an important leadership role through development of its National Strategy for Pandemic Influenza and through its coordinated planning activities.
World Health Organization (WHO) has taken the leading international role.
Governments and other organizations around the world are working together to prepare and respond in the event of a pandemic.

## National Strategy for Pandemic Influenza 

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- National Strategy for Pandemic Influenza

- Preparedness and Communication
- Surveillance and Detection
- Response and Containment

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
The U.S. National Strategy guides the nation’s preparedness and response to an influenza pandemic with the intent of 1) stopping, slowing or otherwise limiting the spread of a pandemic to the United States; 2) limiting the domestic spread of a pandemic and mitigating disease, suffering and death; and 3) sustaining infrastructure and mitigating impact to the economy and the functioning of society.  The three pillars of the National Strategy are:
Preparedness and Communication
Surveillance and Detection
Response and Containment
You can find out more about the U.S. strategy through the www.pandemicflu.gov website. 

## CDC’s Role in Pandemic Preparation and Response 

- Selected examples:
- Conducts and supports clinical and virological influenza surveillance.
- Coordinates pandemic response activities with state, local and tribal public health agencies.
- Coordinates antiviral and other drug delivery from the Strategic National Stockpile.

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
CDC has important roles in all three areas, as seen in the following selected examples:
Conducting and supporting clinical and virological influenza surveillance.
Coordinating pandemic response activities with state, local and tribal public health agencies.
Coordinating antiviral and other drug delivery from the Strategic National Stockpile.

## What Individuals and Families Can Do to Prepare for a Pandemic

- Store a supply of water, food, medical, health and emergencies supplies.
- Talk with family members and loved ones about how they would be cared for if they got sick or what will be needed to care for them in your home.
- Teach your children to wash hands frequently with soap and water, and model the correct behavior.

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
CDC and HHS have prepared checklists to help individual and families, organizations, and others plan for a pandemic.  (Read slide)

## What Individuals and Families Can Do (continued)

- Teach your children to cover coughs and sneezes with tissues, and be sure to model that behavior.
- Teach  your children to stay away from others as much as possible if they are sick.  Stay home from work and school if sick.
**Complete pandemic influenza checklist for individuals and families:**** **www.pandemicflu.gov/planguide/checklist.html

- www.pandemicflu.gov   www.cdc.gov/flu

## What Businesses Can Do to Prepare for a Pandemic

- Plan for the impact on your business
- Plan for the impact on your employees and customers
- Establish policies to be implemented during a pandemic
- Allocate resources to protect your employees and customers during a pandemic
**Complete pandemic influenza checklist for businesses: **www.pandemicflu.gov/plan/businesschecklist.html

- www.pandemicflu.gov   www.cdc.gov/flu

## What Faith-based and Community Organizations Can Do to Prepare for a Pandemic

- Plan the impact of a pandemic on your organization and its mission.
- Communicate with and educate your staff members and persons in the communities that you serve.
- Plan for the impact of a pandemic on your staff, members and the communities you serve.

- www.pandemicflu.gov   www.cdc.gov/flu

## What Faith-based and Community Organizations Can Do (continued)

- Communicate to and educate your employees
- Coordinate with external organizations and help your community
**Complete pandemic influenza checklist for faith-based and community organizations:**
- www.pandemicflu.gov/plan/pdf/faithbasedCommunityChecklist.pdf

- www.pandemicflu.gov   www.cdc.gov/flu

## What Health Care Providers Can Do to Prepare for a Pandemic

- Health care providers play an essential role in the detection of an initial case of novel or pandemic influenza in a community. Early identification and isolation of cases may help slow the spread of influenza within a community.
**Clinical guidelines:** www.hhs.gov/pandemicflu/plan/sup5.html

- www.pandemicflu.gov   www.cdc.gov/flu

## Summary	

- Another pandemic is probably inevitable.
- We are facing an unknown, but increased risk of a pandemic.
- H5N1 will likely persist/recur in Asia, Europe, and Africa and may spread to other parts of the world.
- H5N1 is a “new” virus to humans and can cause severe disease; person-to-person spread has been very limited.

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
What are the important things to remember? 
First, another pandemic is probably inevitable; we are facing an unknown but increased risk of a pandemic. 
It is likely that the spread of H5N1 virus will persist or recur in Asia, Europe, and Africa, especially among birds, and the virus may spread to other parts of the world, including the United States.
A strain of the H5N1 virus is the leading candidate as a potential pandemic threat at this point. It is a “new” virus that has caused severe disease in people; human-to-human transmission has been very limited.

## Summary (continued)

- No evidence now of sustained H5N1 transmission among people
- H5N1 is a leading pandemic candidate, but
- must continue to monitor other avian influenza viruses.
- must push forward pandemic preparedness actions **BEFORE** final warning signs are detected.

- www.pandemicflu.gov   www.cdc.gov/flu

**Notes:**
There is no pandemic at this point, because there is no evidence of sustained transmission of H5N1 viruses among people.
Finally, although a strain of the H5N1 virus is the leading candidate at this point, influenza pandemics can begin anywhere in the world and can potentially be caused by other influenza A viruses. 
We must work together to prepare now – before final warning signs of an influenza pandemic are detected.

## Resources

- _[www.cdc.gov/flu](http://www.cdc.gov/flu)_
- _[www.cdc.gov/flu/workplace](http://www.cdc.gov/flu/workplace)_
- _[www.cdc.gov/flu/school](http://www.cdc.gov/flu/school)_
- _[www.cdc.gov/flu/professionals/index.htm](http://www.cdc.gov/flu/professionals/index.htm)_
- _[www.pandemicflu.gov](http://www.pandemicflu.gov/)_
- _[www.medicare.gov/health/flu.asp](http://www.medicare.gov/health/flu.asp)_

- www.pandemicflu.gov   www.cdc.gov/flu