Pandemic influenza is one of the greatest infectious disease threats facing the world. A pandemic is a disease epidemic that affects a large proportion of the population over a wide geographic area. In the worldwide pandemic influenza attacks of 1918, 1958, and 1968, about 30% of the U.S. population developed some degree of illness. It is likely that another pandemic will strike the same percentage of the population. With about 301,717,000 people in the United States in 2007, a pandemic could sicken over 90 million people in America alone.
There is little doubt in the medical community that a pandemic will strike—only its timing, severity, and exact microbial strain (type) remain unknown. If a pandemic is severe, the effects of it will be far-ranging. Damage to critical infrastructure will have both economic and social consequences. Accordingly, a number of governments, mostly in developed nations, along with the World Health Organization (WHO), have developed plans to tackle an influenza pandemic.
Influenza is a respiratory disease that historically has killed more people than the Black Death (plague). The dead are usually those with weakened immune systems, typically the already-ill, the very young, or the very old. However, the average age of death during the Spanish Influenza pandemic of 1918 was 33. Otherwise healthy adults in that deadly year may have produced an intense localized inflammation that overwhelmed their bodies. Transmission of the next pandemic may be from human to human or, in the possible case of avian flu, initially from bird to human.
Public health experts anticipate a gap between the supply of vaccine and the demand for vaccine during an influenza pandemic. To reduce the impact of an influenza pandemic, the WHO recommends a non-pharmaceutical approach, such as infection control, as well as a pharmaceutical approach, such as the use of vaccines and anti-viral medications for treatment and prophylaxis. Unfortunately, the availability of a pandemic vaccine will be delayed for several months after influenza first appears because of the requirements for vaccine formulation and production. The widespread nature of a pandemic means that there will be insufficient production capacity to supply everyone seeking vaccine with medication, at least in the initial months of an outbreak.
For these reasons, pandemic planning must include the assumption that a range of individuals will be struck down by disease. The U.S. government estimates that 40% or more of workers may be out sick or afraid to go to work for fear of exposure. Community outbreaks may last for six to eight weeks, with multiple waves of disease outbreaks in a calendar year. Further complicating the situation, today's highly mobile population may result in simultaneous disease outbreaks throughout the nation.
A pandemic will likely dramatically reduce the number of workers available to provide goods and services. As a result, the critical infrastructure (food, banking, water, energy, telecommunications, transportation, postal and shipping, emergency services, healthcare) and key resources (government facilities, dams, nuclear power plants, commercial facilities) will lack the staff to function without interruption.
WORDS TO KNOW
CASE FATALITY RATIO: A ratio indicating the amount of persons who die as a result of a particular disease, usually expressed as a percentage or as the number of deaths per 1,000 cases.
PANDEMIC: Pandemic, which means all the people, describes an epidemic that occurs in more than one country or population simultaneously.
QUARANTINE: Quarantine is the practice of separating people who have been exposed to an infectious agent but have not yet developed symptoms from the general population. This can be done voluntarily or involuntarily by the authority of states and the federal Centers for Disease Control and Prevention.
STRAIN: A subclass or a specific genetic variation of an organism.
IN CONTEXT: TERRORISM AND BIOLOGICAL WARFARE
Pandemic preparedness programs may also help safeguard against potential bitoterrorism. One example is the National Pharmaceutical Stockpile Program (NPS). The stockpile of antibiotics, vaccines, and other medical treatment countermeasures can be rapidly deployed to the site of a domestic attack. For example, in the aftermath of the deliberate release of Bacillus anthracis (the bacteria that causes anthrax) in 2001, the U.S. government and some state agencies were able to quickly provide an antibiotic called ciprofloxacin (Cipro) to those potentially exposed to the bacterium.
Following these bioterrorist attacks, increased funding for the NPS was authorized. The additional funds were designated to help train medical personnel in the early identification and treatment of disease caused by the most likely pathogens.
Advocates of increased research capabilities argue that laboratory and hospital facilities must be increased and modernized to provide maximum scientific flexibility in the identification and response to biogenic threats. The CDC has already established a bioterrorism response program that includes increased testing and treatment capacity along with an enhanced ability to recognize and respond to the illness patterns that are characteristic of the deliberate release of an infectious agent.
In 2005, U.S. President George W. Bush announced a comprehensive plan to prepare for and combat pandemic influenza. The plan emphasizes the need for all levels of government and the private sector to cooperate in developing a response. In 2006, the U.S. Homeland Security Council distributed The National Strategy for Pandemic Influenza Implementation Plan. It requires federal government departments and agencies to develop operational plans addressing the protection of employees, the maintenance of essential functions and services, support for federal responses, and communication about pandemic planning and response. State, local, and tribal governments bear the responsibility for limiting an outbreak within and beyond the community's borders, establishing plans, educating key spokespersons in risk communication, providing public education on pandemic influenza, and establishing stockpiles of essential goods. The plan also includes a pandemic severity index that uses case fatality ratios (the proportion of deaths among persons with a particular illness) to make specific recommendations for action based upon the impact of the pandemic.
With 83% of critical infrastructure in the United States in the hands of the private sector, developing individual and system-wide business continuity plans are a priority for planning for a possible pandemic. Businesses should assess the regulations and issues that could affect their supply chain, transportation, priority for municipal services, and workplace safety. Companies, such as restaurants, that rely on unavoidable public contact and those with shared workplaces, such as plants, will be especially hard-hit by limitations on face-to-face encounters.
It is possible that a pandemic response might involve closing places of assembly, isolating those with the disease, quarantining people who have been exposed to the disease, and furloughing non-essential workers. Mean-while, the WHO has developed a Global Vaccine Action Plan to increase the supply of a vaccine during an influenza pandemic and thereby reduce the expected gap between supply and demand.
During a pandemic, governmental agencies such as the Centers for Disease Control and Prevention will play a key role in tracking the disease, assisting state health agencies, and distributing key personnel and medical supplies. Planning at the community level is also important to maintain vital services during a pandemic, while limiting the spread of the disease. In the following excerpt from a guidebook for communities planning for a pandemic, the CDC recommends measures that promote limiting social contact during a pandemic, such as closing schools and voluntary quarantine for those who are ill with the disease.
Community Strategy for Pandemic Influenza Mitigation in the United States
The pandemic mitigation framework that is proposed is based upon an early, targeted, layered application of multiple partially effective nonpharmaceutical measures. It is recommended that the measures be initiated early before explosive growth of the epidemic and, in the case of severe pandemics, that they be maintained consistently during an epidemic wave in a community. The pandemic mitigation interventions described in this document include:
- Isolation and treatment (as appropriate) with influenza antiviral medications of all persons with confirmed or probable pandemic influenza. Isolation may occur in the home or healthcare setting, depending on the severity of an individual's illness and/or the current capacity of the healthcare infrastructure.
- Voluntary home quarantine of members of households with confirmed or probable influenza case(s) and consideration of combining this intervention with the prophylactic use of antiviral medications, providing sufficient quantities of effective medications exist and that a feasible means of distributing them is in place.
- Dismissal of students from school (including public and private schools as well as colleges and universities) and school-based activities and closure of childcare programs, coupled with protecting children and teenagers through social distancing in the community to achieve reductions of out-of-school social contacts and community mixing.
- Use of social distancing measures to reduce contact between adults in the community and workplace, including, for example, cancellation of large public gatherings and alteration of workplace environments and schedules to decrease social density and preserve a healthy workplace to the greatest extent possible without disrupting essential services. Enable institution of workplace leave policies that align incentives and facilitate adherence with the nonpharmaceutical interventions (NPIs) outlined above.
- All such community-based strategies should be used in combination with individual infection control measures, such as handwashing and cough etiquette. Implementing these interventions in a timely and coordinated fashion will require advance planning. Communities must be prepared for the cascading secondand third-order consequences of the interventions, such as increased workplace absenteeism related to child-minding responsibilities if schools dismiss students and childcare programs close.
Centers for Disease Control and Prevention
CENTERS FOR DISEASE CONTROL AND PREVENTION. “INTERIM PRE-PANDEMIC PLANNING GUIDANCE: COMMUNITY STRATEGY FOR PANDEMIC INFLUENZA MITIGATION IN THE UNITED STATES.” WASHINGTON, DC: U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES, FEBRUARY 2007, PAGE 8. ALSO AVAILABLE ONLINE AT < HTTP://WWW2A.CDC.GOV/PHLP/DOCS/COMMUNITY_MITIGATION.PDF>
U.S. Department of Health and Human Services. “Pandemic Flu.gov.” April 26, 2007. <http://www.pandemicflu.gov/index.html> (accessed April 28, 2007).
World Health Organization. “Epidemic and Pandemic Alert Response.” 2007. <http://www.who.int/csr/disease/influenza/nationalpandemic/en/index.html> (accessed April 28, 2007).
World Health Organization. “Global Pandemic Influenza Action Plan to Increase Vaccine Supply.” 2006. <http://www.who.int/vaccines-documents/DocsPDF06/863.pdf> (accessed April 28, 2007).
Caryn E. Neumann