Pandemic Influenza

A pandemic occurs over a wide geographic area and affects a large segment of the population. An influenza pandemic is a global outbreak that results from the emergence of a new influenza virus that can cause serious illness in humans and spreads easily from person to person.

What's the difference between a pandemic and a seasonal outbreak of influenza? +

Influenza pandemics are caused by a virus that is "novel" (new) or different from flu viruses that circulated previously. Because people have no or little natural resistance to a new virus, and there is no readily-available vaccine, influenza pandemics often cause more severe illness and death.

Seasonal influenza outbreaks are caused by small changes in the common influenza viruses. Even though these viruses may change slightly from one flu season to another, many people have developed some immunity. Because similar viruses have circulated previously, vaccine is more readily available.


When will the next pandemic occur? +

No one can predict when a pandemic might occur, but many scientists around the world are watching the H5N1 avian influenza situation in Asia and Europe very closely. They are preparing for the possibility that the virus in birds may change and become more easily transmissible among people.

Influenza pandemics are known to have occurred several times each century since the Middle Ages. There were three influenza pandemics in the twentieth century, in 1918, 1957 and 1968, and so far one has occurred in the 21st Century, in 2009.


What is the New York City Health Department doing to prepare for a possible flu pandemic? +

The Health Department is working with many organizations and partners, including the medical community, city hospitals and state and federal health officials, to prepare for a possible flu pandemic in N Y C. Planning includes making sure hospitals are ready to treat patients and educating doctors and all New Yorkers. The Department has systems to identify where and when flu viruses occur, and to help communicate quickly with doctors and the public about how to avoid infection.


Why is there concern about the H5N1 avian influenza outbreak in Asia and other countries? +

Although it is unpredictable when the next pandemic will occur and what strain of flu virus will cause it, the continued and expanded spread of a severe form of avian influenza in birds across eastern Asia and into a few countries in Europe and Africa represents a significant threat.

This bird flu virus, known as H5N1, has raised concerns about a potential human pandemic because:

  • This H5N1 virus is widespread and persistent in poultry in many countries in Asia and has spread to birds in several countries in Europe;
  • The virus has been transmitted from birds to a few species of mammals and in some limited circumstances to humans;
  • Among humans known to have become infected with the avian H5N1 virus, most have developed serious illness, and more than half have died;
  • Wild birds and domestic ducks have been infected without showing symptoms and have become carriers of viral infection to domestic poultry species;
  • Although most humans who were infected with the H5N1 virus had close contact with infected birds, a few cases of limited person-to-person transmission have been reported;
  • Genetic studies confirm that this H5N1 influenza virus, like other influenza viruses, is continuing to change; and
  • This H5N1 influenza virus may change in a way that enables it to be easily transmitted from person to person.


Will H5N1 cause the next influenza pandemic? +

Scientists cannot predict whether the H5N1 avian influenza virus will cause a pandemic. But federal, state and local health officials are working with their counterparts across the world to track H5N1 as it occurs in birds, and to watch for possible human cases.


Is H5N1 the only avian influenza virus that may cause a pandemic? +

Although H5N1 may pose the greatest current pandemic threat, other avian influenza viruses have infected people in recent years. For example, in 1999, human H9N2 infections were identified in Hong Kong; in 2002 and 2003, human H7N7 infections occurred in the Netherlands and human H7N3 infections occurred in Canada. These viruses also have the potential to cause the next pandemic.


Is there a pandemic influenza vaccine? +

If a pandemic were to occur, officials of the Centers for Disease Control and Prevention (CDC) would quickly work with partners in universities and industry, as well as state and local health authorities, to produce a vaccine that would be available for use within a few months of the start of the outbreak.


Why wouldn't a vaccine be immediately available? +

Large amounts of vaccine cannot be made before knowing exactly which virus is causing a pandemic. Production of a new vaccine takes approximately six months.


Why won't the annual influenza vaccine protect people against pandemic influenza? +

Influenza vaccines are designed to protect against specific viruses that have already been identified. A pandemic vaccine cannot be produced until a new influenza virus emerges and starts to cause a significant number of human illnesses. A virus that could cause a pandemic would be very different from the seasonal flu viruses for which there is already vaccine.


Can I get the vaccine once it has been developed? +

Very few people would be able to get vaccinated at first. If a pandemic occurs, federal, state and local governments will work with partner organizations to make specific recommendations on the early use of vaccine. Current recommendations are to target limited vaccine supplies to people at high risk and healthcare workers.


What are influenza antiviral medications? +

They are prescription drugs that can reduce influenza symptoms and shorten the length of time people are sick. The drugs may also make a person less likely to spread influenza to others. To be effective, they should usually be taken within two days of becoming sick. Some antiviral medications may also be used to prevent influenza if they are taken over a long period of time (for example, if someone had a medical reason that they could not receive the vaccine).


Are there enough antiviral medications for everyone if a pandemic occurred now? If not, who will get them? +

The government has stockpiled antiviral medications and continues to make recommendations about who should be the first to receive antiviral medications based on their risk, role in fighting the pandemic and severity of illness. Discussion continues on the best way to allocate these medications.


How would an influenza pandemic affect our communities? +

The effects of a pandemic could be severe. Many people could become sick at the same time and be unable to go to work. Many people might have to stay at home to care for sick family members. Schools and businesses might close for a time to try to reduce the spread of disease. Large group gatherings might be canceled.


What can I do to prepare for a possible pandemic? +

By taking simple but critical steps, anyone can help prevent the spread of influenza.

  • Cover your mouth and nose with a tissue when coughing and sneezing. Throw away the tissue in the nearest wastebasket and wash your hands.
  • If you don't have a tissue, don't cough or sneeze into your hand. Instead, cough or sneeze into the crook of your arm so you won't get germs on your hands and spread them to others.
  • Wash your hands often with soap and water. When hand washing is not possible, use antiseptic hand gels that contain alcohol.
  • Stay at least three feet from people who are coughing or sneezing.
  • Always practice good hand washing after contact with an ill person or soiled materials, such as tissues.
  • Stay home when you are sick.
  • Keep your children home from school or daycare when they are sick.
  • If you go to the doctor's office or emergency department when you are coughing or sneezing, ask for a mask.
  • Keep a supply of non-perishable food and other essential household items on hand so you can minimize trips to stores and other crowded places in the event of a pandemic.
  • Learn more about the importance of a good home preparedness plan. Visit the federal government's P


How will I cope? +

A flu outbreak in NYC can be very stressful, especially if it is large scale event. It can disrupt your everyday life and make you and those around you feel less safe. You may experience fear and uncertainty. Learning about stress and strategies to manage it can help you cope.

Prepare Today, Cope Better Tomorrow - Stress During Disasters provides basic information and practical advice on dealing with the stress and anxiety caused by disasters. It is available in seven languages.

If there is a flu outbreak in the city and you feel overwhelmed and unable to cope, or if you are concerned about someone else, you can find help by calling (888) NYC-Well (888-692-9355). NYC Well is a free, confidential helpline for New York City residents, available 24/7, with trained staff ready to take your calls and offer advice.


For more information about influenza, visit, Centers for Disease Control and Prevention (CDC)