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