Influenza Pandemic Preparation and Response: A Citizen's Guide

The term is used very loosely in everyday language. The terms influenza and flu are used interchangeably and we are not describing other ordinary seasonal respiratory viral infections.

Seasonal Flu

• Outbreaks follow predictable seasonal patterns; occur annually, usually in winter, in temperate climates
• Usually some immunity built up from previous exposure
• Healthy adults usually not at risk for serious complications; the very young, pregnant women, the elderly and those with certain underlying health conditions at increased risk for serious complications
• Health systems can usually meet population and individual patient needs
• Vaccine developed based on the known circulating flu strains and is available for annual flu season
• Adequate supplies of antivirals are usually available
• Average U.S. deaths approximately 36,000 per year
• Symptoms: fever, cough, runny nose, muscle pain.

Deaths often caused by complications, such as pneumonia.

• Generally causes modest impact on society (e.g., some school closing, encouragement of people who are sick to stay home)
• Manageable impact on domestic and world economy

Pandemic Flu

• Occurs rarely (three times in 20th century - last in 1968)7
• No previous exposure; little or no pre-existing immunity
• In addition to usual populations at risk for severe complications during outbreaks of seasonal influenza, healthy people may be at increased risk for serious complications
• Health systems may be overwhelmed
• Effective vaccines probably would not be available in the early stages of a pandemic
• Effective antivirals may be in limited supply
• Number of deaths could be quite high (The 1918 flu killed 2.6 percent of those who got sick, killing 50-100 million people.8)
• Symptoms may be more severe, with complications and unusual symptoms more frequent
• May cause major impact on society (e.g., widespread restrictions on travel, closings of schools and businesses, cancellation of large public gatherings)
• Potential for severe impact on domestic and world economy

Flu Facts

Seasonal influenza is responsible for an average of 40,000 deaths every year in the United States

Although seasonal influenza may commonly have a greater impact on the young, the old and immuno-compromised individuals, a pandemic influenza can cause serious illness in people of any age.

Currently, H5N1 has caused the most deaths in people between the ages of 10 and 40.

Antibacterial agents are antibiotics that may be used to treat bacterial complications of influenza; these agents, however, are not active against viruses and therefore cannot be used to treat influenza.

The effective use of antiviral agents to treat influenza depends on prompt treatment after exposure or early in the course of the illness - usually during first 48 hrs.

Such a strategy has the potential to significantly reduce the spread of influenza in the community and to modify the severity of disease in individuals.

Each virus has its own characteristics that make vaccines effective against only one type.

Scientists are able to predict how the seasonal virus may look, but a pandemic virus will be unknown until it actually hits.

Being indoors where a virus can breed and be passed on from one person to the next is a perfect way to pass on the illness.

You cannot be infected with the exact same version of influenza twice, but you can be infected with a newly mutated form of an influenza strain. That is, once your body has been exposed to a particular strain of the virus, you will develop immunity and will no longer be susceptible to further infection from that strain.

If the strain mutates enough, you may be susceptible to the mutated strain.

What does the flu look like?

Influenza can encompass any or all of the following symptoms

• Begins abruptly
• Symptoms include fever, chills, body aches, loss of appetite, headache, and fatigue
• Fever (>100.4 F) usually lasts 2-3 days
• Respiratory tract symptoms include cough without phlegm, sore throat, and congestion
• Temperature greater than 100.4 F

It's important to note that pandemic flu symptoms may look very different from seasonal flu symptoms.

Other pandemic symptoms can include

• Stomach and intestinal issues, such as diarrhea, nausea, and vomiting (most often seen in children)
• Sluggishness or alterations in mental state (seen most often in the elderly and infants)
• Pneumonia can often result as a secondary infection (most often seen in those with immuno-compromised systems)
• Viruses are more easily transmitted in closed situations (indoors)

How Does Flu Spread From One Person to Another?

Large droplet transmission:

Respiratory droplets are generated by a person coughing or sneezing and can be propelled right into the eyes, nose, or mouth of other individuals over short distances.

Large droplets are about the size of a droplet of water in fog or mist, or the width of a cotton fiber, and they contain viral particles. Large droplets usually travel about the distance of an extended arm, or about a yard.

This is why infection control advice suggests that people keep greater than an arm's length from each other to avoid transmission.

Small droplet/airborne transmission:

Transmission through ventilation systems in buildings and over other long distance is not likely, but it is possible for saliva particles to stay in the air for a period of time in a room.

These tiny particles can hang around in the air in a room without circulation and can be inhaled. This type of transmission can be lessened with the use of masks and by keeping windows open.

Contact transmission:

Contact can occur by direct bodily contact (such as kissing) or touching something with virus on it (such as shaking hands with someone who has the flu) and then touching your mouth, nose, or eyes.

Viruses can last approximately 48 hours on an object. Regularly washing your hands and keeping common surfaces clean can reduce the occurrence of this type of transmission.

Healthy Habits and Virus Prevention

The main responsibility for effective infection control rests on the contribution of each individual toward reducing the spread of the virus.