Currently there is no pandemic flu in the world. An influenza pandemic is a global outbreak of disease that occurs when three conditions are met: a new influenza A virus appears or "emerges" in the human population, it causes serious illness in people, and it spreads easily from person to person worldwide.
If there were a global outbreak of pandemic influenza, it would be from a new influenza A virus that is unlike past influenza viruses. Because people have not been infected with a similar virus in the past, most or all people will not have natural immunity to a new pandemic virus.
How is Pandemic Influenza Different from Seasonal and Avian Influenza?
- Annual/Seasonal Flu: Annual/seasonal flu usually occurs every year from November through April with the peak usually in January and February. This year, we anticipate adequate supplies of vaccine, but there are delays in distributing it to providers. Typically, annual/seasonal flu results in 1,000 deaths each year in North Carolina , mainly in the very old and very young.
- Pandemic Flu: Pandemic flu can emerge any time during the year. It results from a new flu virus that becomes easily transmitted from human to human. Because it is new, no one has antibodies (or developed an immunity) to this virus and a vaccine would not yet exist. The projected number of deaths for North Carolina would be around 5,600 and not necessarily affecting just the old or young. There have been three flu pandemics in the 1900s: the Spanish Flu in 1918 (550,000 deaths in the US); the Asian flu in 1957 (69,800 deaths in the US); and the Hong Kong Flu in 1968 (33,800 deaths in the US ).
- Avian Flu: This type of flu virus infects birds and has the potential to cause a pandemic. The current Avian Flu virus circulating in birds in Southeast Asia has been associated with some transmission to humans. Currently it is not easily transmitted from human to human. It is not certain whether or not the Avian Flu will emerge in a pandemic form in humans. However, this flu is the focus of a worldwide public health monitoring effort. Over the past 18 months there have been 117 cases in four Asian countries resulting in 60 deaths.
Is a Vaccine Available?
Vaccines are formulated every year to match the type of influenza virus circulating that year. Scientists from around the world work together to select the virus strain most likely to cause flu outbreaks each year. This strain is used by manufacturers to produced vaccine that will offer the best protection against the flu outbreaks. It generally takes 4-8 months to produce influenza vaccine.
Once a potential pandemic strain of influenza virus is identified, a vaccine probably would not be available in the early stages of a pandemic. As with other influenza viruses, it will take several months to manufacture a vaccine to combat the viral strain of concern.
The Impact of a Pandemic: How Serious Might the Impact It Be?
There's no simple answer to the question of how serious a pandemic might be. The 1918 Spanish flu is an example of a worst-case scenario because the strain was highly contagious and quite deadly. This pandemic killed more Americans than all the wars of the 20th century. Since our world today is vastly more populated and people travel the globe with ease, the spread of the next pandemic could be more rapid than previous pandemics. However, other elements of our society have also changed since 1918, such as medical care. Also, the nature of the next pandemic virus is unknown. While looking back at history might provide some clues, a precise estimate of the impact of pandemic flu is not possible. To answer this question we must consider how virulent (or severe) the virus is, how rapidly it can spread from population to population, the health status of those infected, and the effectiveness of influenza prevention and response efforts. Planning for pandemic flu intervention has been underway globally, nationally, and locally for some time and deficiencies identified are being addressed. The influence of the other factors will have on influenza severity are largely unknown.
It's important to note that the impact of a pandemic isn't measured only by how many people will die. If millions of people get sick at the same time, major social consequences will occur. If many doctors and nurses become ill, it will be difficult to care for the sick. If the majority of a local police force is infected, the safety of the community might be at risk. If air traffic controllers are all sick at once, air travel could grind to a halt, interrupting not only business and personal travel, but also the transport of life-saving vaccines or anti-viral drugs. Therefore, a vital part of pandemic planning is the development of strategies and tactics to address all these potential problems.
How Does an Influenza Pandemic Start?
There are three main types of influenza viruses: A, B, and C. Influenza C causes only mild disease and has not been associated with widespread outbreaks. Influenza types A and B, however, cause epidemics nearly every year. Influenza A viruses are divided into subtypes, based on differences in two surface proteins: hemagglutinin (H) and neuraminidase (N). Influenza B viruses are not divided into subtypes. During an influenza flu season, usually one or more influenza A subtype and B viruses circulate at the same time.
A pandemic is possible when influenza A virus makes a dramatic change in its genetic makeup (i.e., "antigenic shift") and acquires a new H or H+N surface protein(s). This shift results in a new or "novel" virus to which the general population has no immunity. The appearance of a novel virus is the first step toward a pandemic. However, the novel influenza A virus also must spread easily from person to person (and cause serious disease) for a pandemic to occur. Influenza B viruses do not undergo antigentic shift and do not cause influenza pandemics.
The reservoir for Type A influenza viruses is wild birds, but influenza A viruses also infect animals such as pigs and horses, as well as people. The last two pandemic viruses were combinations of bird and human influenza viruses. Many persons believe that these new viruses emerged when an intermediate host, such as a pig, was infected by both human and bird influenza A viruses at the same time. A new virus was created and passed along to humans from sick intermediate hosts. Events in Hong Kong in 1997, however, showed that this is not the only way that humans can become infected with a novel virus. Sometimes, an avian influenza virus can "jump the species barrier" (such as pigs) and move directly from chickens to humans and cause disease.
Since, by definition, a novel virus is a virus that has never previously infected humans, or hasn't infected humans for a long time, it's likely that almost no one will have immunity, or antibody to protect them against the novel virus. Therefore, anyone exposed to the virus--young or old, healthy or weak--could become infected and get sick. If the novel virus is related to a virus that circulated long ago, older people might have some level of immunity. It is possible that the novel virus may be especially dangerous to some age groups that are not usually at risk of severe illness or death from annual influenza (such as healthy young adults). Such widespread vulnerability makes a pandemic possible and allows it to have potentially devastating impact.
How Does a Pandemic Spread?
Pandemic influenza would be spread from person to person primarily through "respiratory secretions," the same way seasonal influenza viruses and other common respiratory infections spread. Respiratory secretions (such as spit or mucous) as as virus-containing droplets that are spread when infected persons cough or sneeze. These droplets can then land on the surfaces of the mouth, nose, and throat of persons who are near (i.e., within 3 feet) the ill person. The virus may also be spread through contact with the infectious respiratory secretions on the hands of an infected person and other objects and surfaces.
Adults can spread influenza virus one day before symptoms appear and up to five days after the onset of illness, children up to seven days.
Will the Regular (Seasonal) Flu Shot Provide Any Protection Against the Pandemic Influenza Virus?
Probably not, as the vaccine for seasonal flu was not manufactured to protect against the strain of virus causing the pandemic. Once the virus strain causing the pandemic is known, then vaccines can be produced to prevent its ability to infect people. But the regular flu shot will protect you against the influenza viruses that are circulating right now.
What Is Public Health Doing to Prepare?
The following list is a summary of the local and statewide initiatives on these matters. These resources and preparedness efforts result in Mecklenburg County and the state of North Carolina being better prepared to respond to all types of flu, including pandemic, than ever before.
Mecklenburg County Health Department, Medic (Mecklenburg EMS Agency), Carolinas HealthCare System and Presbyterian Healthcare/Novant Health work as partners to share information on public heath issues and strategize effective and efficient response initiatives.
Mecklenburg County adheres to the North Carolina Pandemic Flu Plan developed in October 2004. This plan is part of a larger and more comprehensive State Emergency Operations Plan.
Mecklenburg is the host county for the Public Health Regional Surveillance Team (PHRST 7), one of seven teams in North Carolina providing the state with increased capacity for early detection and response. This team includes a physician, an epidemiologist, a nurse, a pharmacist, a veterinarian and administrative support.
Mecklenburg County Health Department, Medic, Carolinas HealthCare System, Novant Health and others have participated in multi-agency drills and exercises involving response to infectious disease outbreaks such as Smallpox and have used opportunities such as the annual Influenza Vaccination Clinics to work together and exercise their ability to provide mass vaccination and medication dispensing to large populations during an outbreak event. Plans are in place to address such events such as SARS, smallpox, and overall preparedness plans.
Medic responds to 150 to 300 calls for medical emergencies each day. It is able to monitor the type of call and geographic location. Medic coordinates with both hospital systems and are able to provide early indication of unusual trends such as the early onset of flu levels in December 2003.
Mecklenburg County Health Department has one of three regional bio-level 3 laboratories. Statewide, laboratory capacity for highly infectious and/or chemical agents has doubled, with regional capacity expanded as well.
Mecklenburg County has the Medical On-Line Surveillance Tool (MOST), the electronic syndromic surveillance system that monitors specific sentinel sites such as hospital emergency departments and urgent care centers for unusual trends that could be early indicators of disease outbreaks. The increase in flu syndrome presentations to emergency departments and urgent care centers in December 2003 was also identified by public health officials monitoring the MOST system.
The North Carolina Hospital Emergency Surveillance System (NCHESS) is the first statewide electronic reporting system in the country for hospital emergency departments to report chief complaints from Emergency Department visits to the health department.
North Carolina utilizes a secure early alerting system called HAN (Health Alert Network) with more than 300 users connected. This system will be used for early detection and response.
Carolinas Medical Center houses one of 12 medical epidemiologists located across the state to enhance public health surveillance.
Mecklenburg County Health Department has a full time Public Health Preparedness Coordinator which is funded with state grant money.
Hospital preparedness planners have been established statewide in each of the eight Regional Advisory Committees to strengthen emergency planning and disaster recovery efforts in hospitals. Locally, Carolinas Medical Center houses one of the eight preparedness planners.
North Carolina has an Office of Public Health Preparedness and Response that would provide expertise, guidance, and state-wide coordination in the event of a large pandemic flu outbreak.
Working with the State Office of Emergency Medical Services and The Division of Emergency Management, a tiered statewide system for providing surge medical services, State Medical Assistant Teams, was established. These local, regional and state teams use trained volunteer providers across the state to provide additional medical services during an emergency.
What Can I Do to Prepare?
- Stay informed. These web sites provide regularly updated information about bird flu and pandemic flu:
- Stop germs from spreading.
- Practice good health habits:
- eat a balanced diet
- exercise daily
- get sufficient rest
- Develop preparedness plans as you would for other public health emergencies. See www.ready.gov.
- If you plan to travel to Southeast Asia, check the CDC website for travel advisories.
What Should My Business Do To Pepare?
In the event of pandemic influenza, businesses will play a key role in protecting employees' health and safety as well as limiting the negative impact to the economy and society. Planning for pandemic influenza is critical. To assist you in your efforts, the Department of Health and Human Services (HHS) and the Centers for Disease Control and Prevention (CDC) have developed a checklist for large businesses. It identifies important, specific activities large businesses can do now to prepare, many of which will also help you in other emergencies. Download checklist.
Sources & for more information visit:
Centers for Disease Control, http://www.cdc.gov/flu