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AVIAN/PANDEMIC INFLUENZA
FREQUENTLY ASKED QUESTIONS
WHAT ARE THE BASIC FACTS ABOUT “BIRD” FLU AND A POSSIBLE PANDEMIC? Currently, the term bird flu refers primarily to avian influenza A strain H5N1. However, wild birds are actually reservoirs for all known influenza subtypes. So any influenza A strain has the capacity to be a “bird flu.” Birds tend to carry a large viral burden in their intestines and shed the virus in their saliva, nasal secretions, and feces for up to several weeks. The H5N1 strain was first recognized in Hong Kong in 1997. Over 1.5 million birds were purposely killed or culled in an effort to stop the outbreak. Unfortunately, H5N1 has spread widely through migratory birds and into domestic poultry. Situational updates on the spread of avian influenza can be accessed via http://www.pandemicflu.gov/. The “bird flu” starts out like the ordinary flu, which usually starts suddenly with fever, muscle aches, headache and cough. People with the flu feel ill, often spending several days in bed, but usually recover in three to seven days. With the “bird flu” many people develop a severe pneumonia with persistent fever and trouble breathing. To date, no cases of avian influenza A strain H5N1 have been reported in the United States. Information about monitoring events in the US can be accessed via http://www.pandemicflu.gov/outbreaks/#ussurv. Influenza epidemics and pandemics differ primarily in scope and the mechanisms by which they occur. Epidemics occur every year due to minor changes (AKA mutations) in the influenza viruses that circulate. This results in an upswing of cases over about six weeks in a given community with an associated increase in hospitalizations and deaths. By contrast, pandemics happen only occasionally when a completely new influenza virus starts to circulate resulting in a really large worldwide epidemic often with multiple waves of illness. Pandemics result in more severe illnesses and more deaths than usual…especially if both the H and N components are novel. Nobody knows how likely it is that a pandemic will occur. We are overdue for a pandemic (the last one occurred in 1968). Also, the current bird flu virus has spread widely in birds in Asia, Africa and Europe, killing hundreds of millions of birds, and spreading to about 200 humans. This virus has been around since 1997, and a pandemic has not occurred yet, but there is evidence that this bird flu strain is spreading to more species of animals, and to more humans. It has not become highly contagious, which is needed to have a pandemic. If a pandemic were to occur, it is estimated that 90 million people in the US would be infected. 865,000 to 9.9 million would be hospitalized with 209,000 to 1.9 million deaths. Estimates indicate $71 to $166 billion would be lost and there would be serious social and economic disruptions. More information about a pandemic and associated impacts can be accessed via http://www.pandemicflu.gov/. t Top HOW DOES AVIAN FLU SPREAD IN HUMANS? There is evidence that influenza can spread by contact with virus on surfaces as well as through the air. Droplet spread refers to large droplets expelled by coughing, sneezing or talking. These particles generally settle out of the air within 3 to 6 feet from their origin…generally within “spitting distance.” This is felt to be the most common means by which influenza spreads. So most people who catch influenza get it from an infected person within “spitting distance.” In general, in a pandemic you should avoid crowds and wash hands frequently with soap and water or us an alcohol based waterless agent. If you are ill, avoid contact with others. Use a household disinfectant (such as a 1:10 dilution of bleach) for cleaning surfaces. Wash your hands after handling raw foods. The usual incubation period between the time someone is exposed and infected with influenza virus to the time that they experience symptoms of illness is about 2 days. Unfortunately, viral shedding can actually begin up to a day before the onset of symptoms. Peak shedding of virus generally occurs during the first 3 days of illness and correlates with the presence of fever. The amount of virus shed influences how infectious a sick individual is to those around him/her. The Association for Professionals in Infection Control and the US Department of Health and Human Services offer several recommendations for dealing with influenza patients in the home. · Management of Influenza Patients in the Home o Physically separate the patient with influenza from non-ill persons living in the home as much as possible o Patients should not leave the home during the period when they are most likely to be infections to others (i.e. 5 days after onset of symptoms). When movement outside the home is necessary (e.g. for medical care), the patient should follow respiratory hygiene/cough etiquette (i.e. cover the mouth and nose when coughing and sneezing) and should wear a mask. · Management of Other Persons in the Home o Persons who have not been exposed to pandemic influenza and who are not essential for patient care or support should not enter the home while persons are still having a fever due to pandemic influenza. o If unexposed persons must enter the home, they should avoid close contact with the patient. o Persons living in the home with the patient with pandemic influenza should limit contact with the patient to the extent possible; consider designating one person as the primary care provider. o Household members should be vigilant for the development of influenza symptoms. Consult with healthcare providers to determine whether a pandemic influenza vaccine, if available or antiviral prophylaxis should be considered. · Infection Control Measures in the Home o All persons in the household should carefully follow recommendations for hand hygiene (i.e. hand washing with soap and water or use of an alcohol-based hand sanitizer) after contact with an influenza patient or the environment in which they are receiving care. o Although no studies have assessed the use of masks at home to decrease the spread of infection, using a surgical or procedure mask by the patient or caregiver during interactions may be beneficial. o Soiled dishes and eating utensils should be washed either in a dishwasher or by hand with warm water and soap. Separation of eating utensils for use by a patient with influenza is not necessary. o Laundry may be washed in a standard washing machine with warm or cold water and detergent. It is not necessary to separate soiled linen and laundry used by a patient with influenza from other household laundry. Care should be used when handling soiled laundry (i.e. avoid “hugging” the laundry) to avoid self-contamination. Hand hygiene should be performed after handling soiled laundry. o Tissues used by the ill patient should be placed in a bag and disposed of with other household waste. Consider placing a bag for this purpose at the bedside. o Environmental surfaces in the home should be cleaned using normal procedures. More information about staying healthy during a pandemic can be accessed via http://www.pandemicflu.gov/plan/tab3.html#healthy Eating chicken and eggs is safe. Cook all poultry and meat to an internal temperature of 165 degrees to protect against avian flu and other important bacterial diseases. Eggs must be cooked thoroughly until yolks are firm. Scrambled eggs should not be runny. Casseroles and other dishes containing eggs should be cooked to 160°F as measured with a food thermometer.
WHAT ABOUT PREVENTION AND TREATMENT? Current vaccines do not protect against avian flu, however, it is important to get a regular flu shot every year, especially if you are over 65 or have underlying medical conditions. You should also have the pneumonia vaccine if you are in those same groups. Standard flu that circulates every year and kills an average of 35,000 people in the US primarily affects the elderly and those with chronic illnesses. The 1918 flu, which resembles the bird flu genetically, was more deadly than the standard flu, and affected primarily the young and healthy people, like US soldiers. We will have to see how this pandemic evolves before predictions of this type can be made. It normally takes 4-6 months to develop a vaccine after a new pandemic strain appears, and then 6-12 months more to produce enough vaccine for everyone. By that time the pandemic has done much damage. In an effort to shorten the time needed for development and production, the US has taken the avian flu strain that is causing a pandemic in birds, and testing it in humans. So far it looks promising, but it is a guess if the pandemic strain will be the same one. It is possible that antiviral drugs can be used to treat avian influenza A H5N1. However, we only have laboratory tests and animal experiments on which to rely right now. The H5N1 strain infecting birds and a limited number of humans is resistant to some older influenza drugs, amantadine and rimantadine. CDC recommended in mid-January that these drugs not be used for the remainder of the 2005-06 flu season. However, bird flu strains (and also seasonal influenza strains) are sensitive to the newer neuraminidase inhibitors, oseltamivir (Tamiflu) and Zanamivir (Relenza). The former comes in capsules and suspensions, and the latter is inhaled. Oseltamivir, a relatively new flu medicine, seems to have activity against the bird flu. The medicine is produced in Europe, and there is not enough to treat more than a small percentage of those who would be sickened in a pandemic. The US government and the CDC are working to increase production of this medicine, and to develop a stockpile of it in case of an emergency. Some resistance may develop in bird flu to this medicine, which would compromise its usefulness in a pandemic. Because of concerns about the pandemic potential of H5N1, the World Health Organization (WHO) has been working with laboratories in the WHO influenza network to develop vaccines against avian flu. Candidate vaccines were developed during 2003 by network laboratories in London and in Memphis, Tennessee, for protection against the strain that was isolated from humans in Hong Kong in February of that year. However, the 2004 strain is different from that strain. In April 2004, WHO made the prototype seed strain for an H5N1 vaccine available to manufacturers. The National Institute of Allergy and Infectious Diseases (NIAID) awarded two contracts to support the production and clinical testing of an investigational vaccine based on the prototype seed strain made available by WHO. The contracts were awarded to Aventis Pasteur (now Sanofi Pasteur) of Swiftwater, Pennsylvania, and to ChironCorporation of Emeryville, California. Each manufacturer is using established techniques in which the virus is grown in eggs and then inactivated and further purified before being formulated into vaccines. Clinical trials of candidate H5N1 vaccines are currently under way. On August 6, 2005, NIAID announced that the Sanofi Pasteur vaccine was meeting with positive results in the first wave of testing in healthy adults. However, the amount of antigen needed was 180 mcg versus the 15 mcg given in annual flu shots, which makes the problem of adequate production far more acute. Further testing is ongoing, including trials to determine effectiveness and safety in children and the elderly. At this point, it is not clear if prototype H5 vaccines will offer protection against an emergent pandemic strain. Research in this area is a high priority because stockpiling prototype vaccines may be worthwhile if protection against emergent strains can be demonstrated. One recent study demonstrated good cross-protection against H5N1 in mice following vaccination with an H5 influenza vaccine created through reverse genetics. Protection was achieved despite antigenic differences and incomplete matching between the vaccine strain and the challenge virus. Although these findings are promising, it is not clear if similar protection would occur for humans. A second study suggested that use of adjuvanted prototype vaccines may induce antibody capable of neutralizing a pandemic strain until a well-matched vaccine can be made available. In the study, 14 human subjects vaccinated with an adjuvanted influenza A/duck/Singapore 97 (H5N3) vaccine demonstrated higher seroconversion rates to four strains of H5N1 compared with 11 subjects who were vaccinated with a nonadjuvanted vaccine. For those who received the MF59-adjuvanted vaccine, 100% seroconverted to A/HongKong/156/97 and A/HongKong/213/03, 71% to A/Thailand/16/04, and 43% to A/Vietnam/1203/04. One way of protecting against all types of influenza, including emerging pandemic strains, would be a universal flu vaccine that would not have to be reengineered each year. The British company Acambis announced in early August 2005 that it is developing such a vaccine and has had successful results in animal testing. The vaccine would focus on the M2 viral protein, which does not change, rather than the surface hemagglutinin and neuraminidase proteins targeted by traditional vaccines. The universal vaccine is made through bacterial fermentation technology, which would greatly speed up the rate of production over that possible with culture in chicken eggs, plus the vaccine could be produced continuously, since its formulation would not change. Still, such a vaccine is years away from full testing, approval, and use. Other researchers are also working on a universal agent. The preceding was excerpted directly from the avian influenza section of the IDSA website. The Federal government has developed priority lists to allocate distribution of limited supplies of vaccine should a pandemic occur. Those priority lists reflect the pandemic response goals of:
Priorities for vaccine and antiviral drug use will vary based on pandemic severity as well as the vaccine and drug supply. Nebraska’s pandemic flu vaccination goals include:
The following information is drawn from Table D-1 in the appendix of the Federal HHS Pandemic Influenza plan. Tier 1
Tier 2
Tier 3
Tier 4
Below are some more details about the priority groups. Tier Subtier Population 1A ¦ Vaccine and antiviral manufacturers and others essential to manufacturing and critical support [rationale: Need to assure maximum production of vaccine and antiviral drugs]; Medical workers and public health workers who are involved in direct patient contact, other support services essential for direct patient care, and vaccinators [rationale: Healthcare workers are required for quality medical care (studies show outcome is associated with staff-to-patient ratios). There is little surge capacity among healthcare sector personnel to meet increased demand.] 1B ¦ Persons >_ 65 years with 1 or more influenza high-risk conditions, not including essential hypertension (approximately 18.2 million); Persons 6 months to 64 years with 2 or more influenza high-risk conditions, not including essential hypertension; Persons 6 months or older with history of hospitalization for pneumonia or influenza or other influenza high-risk condition in the past year [rationale:These groups are at high risk of hospitalization and death. Excludes elderly in nursing homes and those who are immunocompromised and would not likely be protected by vaccination] 1C ¦ Pregnant women [rationale:In past pandemics and for annual influenza, pregnant women have been at high risk; vaccination will also protect the infant who cannot receive vaccine.]; Household contacts of severely immunocompromised persons who would not be vaccinated due to likely poor response to vaccine (1.95 million with transplants, AIDS, and incident cancer x 1.4 household contacts per person = 2.7 million persons); Household contacts of children <6 month olds [rationale: Vaccination of household contacts of immunocompromised and young infants will decrease risk of exposure and infection among those who cannot be directly protected by vaccination.] 1D ¦ Public health emergency response workers critical to pandemic response; Key government leaders [rationale: Critical to implement pandemic response such as providing vaccinations and managing/monitoring response activities; Preserving decision-making capacity also critical for managing and implementing a response] 2 A ¦ Healthy 65 years and older; 6 months to 64 years with 1 high-risk condition; 6-23 months old, healthy [rationale: Groups that are also at increased risk but not as high risk as population in Tier 1B] 2B ¦ Other public health emergency responders; Public safety workers including police, fire, 911dispatchers, and correctional facility staff; Utility workers essential for maintenance of power, water, and sewage system functioning; Transportation workers transporting fuel, water, food, and medical supplies as well as public ground public transportation; Telecommunications/IT for essential network operations and maintenance [rationale: Includes critical infrastructure groups that have impact on maintaining health (e.g., public safety or transportation of medical supplies and food); implementing a pandemic response; and on maintaining societal functions] 3 ¦ Other key government health decisionmakers; Funeral directors/embalmers; [rationale: Other important societal groups for a pandemic response but of lower priority] 4 ¦ Healthy persons 2-64 years not included in above categories; [rationale: All persons not included in other groups based on objective to vaccinate all those who want protection] t Top WHAT’S THE GOVERNMENT DOING TO PREPARE? The National Strategy for Pandemic Influenza, issued by President Bush November 1, 2005, guides our 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 Strategy charges the U.S. Department of Health & Human Services with leading the federal pandemic preparedness. The Implementation Plan for the National Strategy, released by the President on May 3, 2006, translates the Strategy into more than 300 actions for Federal departments and agencies and sets clear expectations for State and local governments and other non-Federal entities. It also provides guidance for all Federal departments and agencies on the development of their own plans. The Implementation Plan identifies the critical steps that must be taken immediately and over the coming months and years to address the threat of an influenza pandemic. It assigns specific responsibilities to Departments and Agencies across the Federal Government, and includes measures of progress and timelines for implementation. It also provides initial guidance for State, local, and tribal entities, businesses, schools and universities, communities, and Non-Governmental Organizations (NGOs), on the development of their institutional plans and provides initial guidance for individuals and families on ways that they can prepare for a pandemic. An overview of the plan can be found here in English and Spanish: Implementation Plan Fact Sheet [En Español]. The National Strategy for Pandemic Influenza outlines responsibilities that individuals, industry, state and local governments, and the federal government have for preparing and responding to a pandemic. A copy of the strategy can be found here National Strategy for Pandemic Influenza. Nebraska’s pandemic flu plan is a so-called “evergreen” document meaning that it is constantly being updated. Because prioritizations of scarce health resources like vaccine and anti-viral medicines is an emotionally charged and ethical issue in addition to being a complicated medical one, the governor of Nebraska formed a pandemic flu committee composed of businesspersons, clergy, ethicists, first responders, school officials, infectious diseases experts, the food industry, public health employees, veterinarians, etc. The group was educated about the issues and provided input for recommendations to the governor. A citizen group in conjunction with public health officials from Nebraska and the CDC also was convened. Both groups voiced strong support for PH in developing strategic goals for prioritization of resources. A copy of Nebraska’s plan is available at http://www.hhs.state.ne.us/puh/epi/flu/pandemic/docs/State-Plan.pdf. For information about what is happening on the local level, contact your local Public Health Department: http://www.hhs.state.ne.us/lhd/map.pdf t Top WHAT CAN INDIVIDUALS AND BUSINESSES DO TO PREPARE?
WHAT ABOUT PETS OR OTHER ANIMALS?
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