Denise Cardo, M.D.
Division of Healthcare Quality Promotion
National Center for Infectious Diseases
Centers for Disease Control and Prevention
U.S. Department of Health and Human Services
Avian Influenza: Preparing for a Possible Influenza Pandemic
Veterans' Affairs Subcommittee on Oversight and Investigations
United States House of Representatives
Thursday, December 15, 2005
Mr. Chairman and members of the Subcommittee, I am pleased to be here today to describe the current status of avian influenza around the world; the consequences of a possible human influenza pandemic; and efforts within the Department of Health and Human Services (HHS) to prevent, prepare for and respond to such a pandemic, including the HHS Pandemic Influenza Plan. Thank you for the invitation to testify on influenza pandemic planning and preparedness, which Secretary Mike Leavitt has made a top priority. As you know, the President has requested emergency supplemental funding for the HHS Pandemic Influenza Plan, which is an integral component of his National Strategy for Pandemic Influenza. In the event that an outbreak of pandemic flu hits our shores, it will surely have profound impacts on almost every sector of our society. Such an outbreak will require a coordinated response at all levels of government – Federal, State, and local – and it will require the participation of the private sector and each of us as individuals. HHS has been a leader in this effort. With this budget request and the release of the HHS Pandemic Influenza Plan, we are taking another major step forward to improve our preparedness and response capabilities.
The Centers for Disease Control and Prevention (CDC) and other agencies within HHS are working together formally through the Influenza Preparedness Task Force that Secretary Leavitt has chartered to prepare the United States for this potential threat to the health of our nation. We are also working with other federal, state, local and international organizations to ensure close collaboration.
As you are aware, the potential for a human influenza pandemic is a current public health concern with an immense potential impact. Inter-pandemic (seasonal) influenza causes an average of 36,000 deaths each year in the United States, mostly among the elderly and more than 200,000 hospitalizations. In contrast, scientists cannot predict the severity and impact of an influenza pandemic, whether from the H5N1 virus currently circulating in birds in Asia and Europe, or the emergence of another influenza virus of pandemic potential. However, modeling studies suggest that, in the absence of any control measures, a “medium-level” pandemic in which 15 percent to 35 percent of the U.S. population develops influenza could result in 89,000 to 207,000 deaths, between 314,000 and 734,000 hospitalizations, 18 to 42 million outpatient visits, and another 20 to 47 million sick people. The associated economic impact in our country alone could range between $71.3 and $166.5 billion. A more severe pandemic, as happened in 1918, could have a much greater impact. Estimates based on extrapolations from research on the 1918 pandemic have predicted that a similarly severe pandemic could result in up to 9.9 million hospitalizations and 1.9 million deaths.
There are several important points to note about an influenza pandemic:
- A pandemic could occur anytime during the year and could last much longer than typical seasonal influenza, with repeated waves of infection that could occur over one or two years.
- The capacity to intervene and prevent or control transmission of the virus once it gains the ability to be efficiently transmitted from person to person will be limited.
- Right now, the H5N1 avian influenza strain that is circulating in Asia and Europe among birds is considered the leading candidate to cause the next pandemic. However, it is possible that another influenza virus, which could originate anywhere in the world, could cause the next pandemic. Although researchers believe some viruses are more likely than others to cause a pandemic, they cannot predict with certainty the risks from specific viruses. This uncertainty is one of the reasons why we need to maintain year-round laboratory surveillance of influenza viruses that affect humans.
- We often look to history in an effort to understand the impact that a new pandemic might have, and how to intervene most effectively. However, there have been many changes since the last pandemic in 1968, including changes in population and social structures, medical and technological advances, and a significant increase in international travel. Some of these changes have increased our ability to plan for and respond to pandemics, but other changes have made us more vulnerable.
- The current threat of a human pandemic due to lethal highly pathogenic avian influenza A (HPAI H5N1) should be addressed at both the human and animal levels, recognizing that this is currently an animal disease. But because pandemic influenza viruses will most likely emerge in part or wholly from influenza viruses among animals, such as birds, it is critical for human and animal health authorities to closely coordinate activities such as surveillance and to share relevant information as quickly and as transparently as possible.
The Current Status of H5N1 Virus in Asia
Beginning in January 2004, the World Health Organization (WHO) confirmed reports of new outbreaks of HPAI H5N1 infection among poultry and waterfowl in several Asian countries. In 2005, outbreaks of H5N1 disease have also been reported among poultry in Russia, Ukraine, Kazakhstan, Turkey, and Romania. Mongolia has reported outbreaks of the H5N1 virus in wild, migratory birds. In October 2005, outbreaks of the H5N1 virus were reported among migrating swans in Croatia. In 2004, sporadic human cases of avian influenza A (H5N1) were reported in Vietnam and Thailand. In 2005 additional human cases have been reported in Cambodia, China, Indonesia, Thailand, and Vietnam. Cumulatively, as of December 14, 2005, 138 human cases have been reported and laboratory confirmed by WHO. These cases have resulted in 71 deaths, a fatality rate of approximately 51 percent among reported cases. Almost all cases of H5N1 human infection appear to have resulted from some form of direct or close contact with infected poultry, primarily chickens. In addition, a few persons may have been infected through very close contact with another infected person, but this type of transmission has not led to sustained transmission.
For an influenza virus to cause a pandemic, it must: (1) be a virus to which there is little or no pre-existing immunity in the human population; (2) be able to cause illness in humans; and, (3) have the ability for sustained transmission from person to person. So far, the HPAI H5N1 virus circulating in Asia and Europe meets the first two criteria but has not yet shown the capability for sustained transmission from person to person.
The highly pathogenic avian influenza A (H5N1) epizootic (or animal) outbreak in Asia that is now beginning to spread into Europe is not expected to diminish significantly in the short term. It is likely that H5N1 infection among birds has become endemic in certain countries in Asia and that human infections resulting from direct contact with infected poultry will continue to occur. So far, scientists have found no evidence for genetic reassortment. Reassortment can occur when the genetic code for high virulence in an H5N1 strain combines with the genetic code of another influenza virus strain resulting in a new virus that is more easily transmitted. However, the animal outbreak continues to pose an important public health threat, because there is little preexisting natural immunity to H5N1 infection in the human population.
In October 2005, CDC Director Julie Gerberding accompanied HHS Secretary Mike Leavitt when he led a delegation of U.S. and international health experts on a 10-day trip to five nations in Southeast Asia. The purpose of this trip was: 1) to learn from countries that have had first-hand experience with avian influenza; 2) to emphasize the importance of timely sharing of information and samples in fighting the disease; and, 3) to determine the best use of our resources abroad to protect people in the United States. They learned several important lessons. First, international cooperation is absolutely essential; an outbreak anywhere increases risk everywhere. Second, surveillance, transparency, and timely sharing of information and samples, such as virus strains, are critical. The ability of the United States and the world to contain or slow the spread of an influenza pandemic is highly dependent upon early warning of outbreaks. Finally, it is vital to strengthen preparedness and response capabilities in Asian countries and other parts of the world. The delegation also concluded that pandemic preparedness and preparation must be both short- and long-term in scope. These critical elements form the basis of the Administration’s diplomatic engagement strategy through the International Partnership on Avian and Pandemic Influenza, launched by the President in September, and drives our efforts with the international health community to prepare effectively for a pandemic. As I stated earlier, there is no way to know if the current H5N1 virus will evolve into a pandemic. However, we do know that there have been three pandemics in the past 100 years, and we can expect more in this century.
The Secretary’s trip reaffirmed the value of several actions undertaken by HHS and its agencies over the last few years. It is vital to monitor H5N1 viruses for changes that indicate an elevated threat for humans, and we are continuing to strengthen and build effective in-country surveillance, which includes enhancing the training of laboratorians, epidemiologists, veterinarians, and other professionals, as well as promoting the comprehensive reporting that is essential for monitoring H5N1 and other strains of highly pathogenic avian influenza. In collaboration with international partners and other U.S. Government Agencies, HHS is also pursuing a strategy of active, aggressive international detection; investigation capacity; international containment; and laboratory detection support.
Development and Manufacture of Vaccine
The development and role of a pandemic influenza vaccine is a principal component of the HHS Pandemic Influenza Plan, which I will describe later in the testimony. During an influenza pandemic, the existence of influenza vaccine manufacturing facilities functioning at full capacity in the United States will be critically important. We assume the pandemic influenza vaccines produced in other countries are unlikely to be available to the U.S. market, because those governments have the power to prohibit export of the vaccines produced in their countries until their domestic needs are met. The U.S. vaccine supply is particularly fragile; only one of four influenza vaccine manufacturers that sell in the U.S. market makes its vaccine entirely in the United States.
Another important factor is that public demand for influenza vaccine in the United States varies annually. Having a steadily increasing demand would provide companies with a reliable, growing market that would be an incentive to increase their vaccine production capacity. In FY 2006, CDC will direct $40 million through the Vaccines for Children (VFC) program to purchase influenza vaccine for the national pediatric stockpile as additional protection against annual outbreaks of influenza. To secure a year-round egg supply for egg-based influenza vaccine manufacturing in the U.S. and provide pilot investigational lots of pandemic-like influenza vaccine candidates for clinical evaluation, HHS awarded a contract to sanofi pasteur for $41.8 million in September 2004. HHS also signed a $100 million contract in April 2005 with sanofi pasteur to develop cell culture influenza vaccines and build domestic manufacturing capacity. The President is requesting $4.7 billion in FY 2006 to encourage greater production capacity that will enhance the U.S.-based vaccine manufacturing surge capacity to help prepare for a pandemic and further guard against annual shortages and to develop pandemic vaccines towards licensure utilizing antigen sparing and universal cross subtype vaccine technologies.
Clinical testing of pilot investigational lots of H5N1 vaccine as antigen-alone formulations to determine safety, dosage, and schedule began in April 2005 with funding from NIH. Initial testing shows that, in its current form, a much higher dose of vaccine will be needed to produce the desired immune response in people. To that end HHS and NIH are working with sanofi pasteur, formulations of H5N1 vaccine produced in 2004 at commercial scale and formulated with an adjuvant – aluminum hydroxide- have been manufactured and are scheduled for clinical testing early next year. Other adjuvants and other delivery strategies are under study by the NIH with H5N1 and other avian influenza vaccines. Lastly, HHS awarded contracts in 2005 to sanofi pasteur and Chiron for $180 million and $63 million, respectively, for the commercial scale production of H5N1 vaccine to establish pre-pandemic vaccine stockpiles.
One of the main efforts by HHS in pandemic preparedness is to expand the nation’s use of influenza vaccine during inter-pandemic influenza seasons. This increase will help assure that the United States is better prepared for a pandemic. Influenza vaccine demand drives influenza vaccine supply. As we increase annual production efforts, this should strengthen our capacity for vaccine production during a pandemic. We are also developing strategies to increase influenza vaccine demand and access by persons who are currently recommended to receive vaccine each year.
On November 1, 2005, President Bush released The National Strategy for Pandemic Influenza, which outlines the roles of the Federal government, State and local governments, private and international partners, and individual citizens to prepare for and respond to an influenza pandemic. The following day, Secretary Leavitt introduced the HHS Pandemic Influenza Plan—a blueprint for all HHS pandemic influenza preparedness and response planning. The HHS Plan provides guidance to national, State, and local policy makers and health departments with the goal of achieving a national state of readiness and quick response. The HHS plan also includes a description of the relationship of this document to other federal plans and an outline of key roles and responsibilities during a pandemic. In the event of a pandemic and the activation of the National Response Plan, HHS has a critical role to support the Department of Homeland Security in their role of overall domestic incident management and Federal coordination. CDC will support the responsibilities designated to HHS. The President is requesting additional FY 2006 appropriations for HHS totaling $6.7 billion in support of the HHS Pandemic Influenza Plan. In seeking this funding, the goals are: to be able to produce a course of pandemic influenza vaccine for every American within six months of an outbreak; to provide enough antiviral drugs and other medical supplies to treat over 25 percent of the U.S. population; and to ensure a domestic and international public health capacity to detect and respond to a potential pandemic influenza outbreak.
In addition to outlining the federal response in terms of vaccines, surveillance, and planning, the HHS Pandemic Influenza Plan makes clear the role of individual Americans in the event of an influenza pandemic. The importance of such ordinary but simple steps as frequent hand washing, containing coughs and sneezes, keeping sick children (and adults) home until they are fully recovered are widely seen as practical and useful for helping control the spread of infection. The Plan also describes options for social-distancing actions, such as “snow days” and alterations in school schedules and planned large public gatherings. While such measures are, ordinarily, unlikely to fully contain an emerging outbreak, they may help slow the spread within communities.
State and Local Preparedness and Planning
All states have submitted interim pandemic influenza plans to CDC as part of their 2005 Public Health Emergency Preparedness Cooperative Agreements. Key elements of these plans include the use of surveillance, infection control, antiviral medications, community containment measures, vaccination procedures, and risk communications. To support the federal and state planning efforts, CDC has developed detailed guidance and materials for states and localities, which are included in the HHS Plan. CDC will work with states to build this guidance into their plans. CDC has taken a lead role in working with the Advisory Committee on Immunization Practices (ACIP) and the National Vaccine Advisory Committee (NVAC) which recommend strategic use of antiviral medications and vaccines during a pandemic when supplies are limited.
CDC is working to: (1) ensure that states have sufficient epidemiologic and laboratory capacity both to identify novel viruses throughout the year and to sustain surveillance during a pandemic; (2) improve reporting systems so that information needed to make public health decisions is available quickly; (3) enhance systems for identifying and reporting severe cases of influenza; (4) develop population-based surveillance among adults hospitalized with influenza; and, (5) enhance monitoring of resistance to current antiviral drugs to guide policy for use of scarce antiviral drugs.
Collaboration with the Council for State and Territorial Epidemiologists (CSTE) has considerably improved domestic surveillance through making pediatric deaths associated with laboratory-confirmed influenza nationally notifiable, and by implementing hospital-based surveillance for influenza in children at selected sites. CDC will continue to work with CSTE to make all laboratory confirmed influenza hospitalizations notifiable. Since 2003, interim guidelines have been issued to states and hospitals for enhanced surveillance to identify potential H5N1 infections among travelers from affected countries, and these enhancements continue. Special laboratory training courses to teach state laboratory staff how to use molecular techniques to detect avian influenza have been held. In the past year, CDC trained professionals from all of the 48 states that desired training.
If an influenza pandemic were to occur in the United States, it would place a huge burden on the U.S. healthcare system. Medical surge capacity may be limited, and could be vastly outpaced by demand. Healthcare facilities need to be prepared for the potential rapid pace and dynamic characteristics of a pandemic. All facilities should be equipped and ready to care for a limited number of patients infected with a pandemic influenza virus as part of normal operations as well as a large number of patients in the event of escalating transmission. Preparedness activities of healthcare facilities need to be synergistic with those of other pandemic influenza planning efforts. Effective planning and implementation will depend on close collaboration among state and local health departments, community partners, and neighboring and regional healthcare facilities. However, despite planning, in a severe pandemic it is possible that shortages in staffing, beds, equipment (e.g., mechanical ventilators), and supplies will occur and medical care standards may need to be adjusted to most effectively provide care and save as many lives as possible.
CDC has developed, with input from state and local health departments and healthcare partners, including other federal agencies, guidance that provides healthcare facilities with recommendations for developing plans to respond to an influenza pandemic and guidance on the use of appropriate infection control measures to prevent transmission during patient care. Development of and participation in tabletop exercises over the past two years have identified gaps and provided recommendations for healthcare facilities to improve their readiness to respond and their integration in the overall planning and response efforts of their local and state health departments. These exercises were valuable in showing the importance of having existing, accessible lines of communication and points of contact to facilitate the response both within the facility and between the facility and other response partners in the community. The tabletop exercises were also an important tool for directing facilities in how to set up an incident command structure and to assign staff to rapidly engage with the command structure. The healthcare system has made great strides in preparation for a possible pandemic, but additional planning still needs to occur.
Collaborations with the Department of Veterans Affairs
VA is participated in working groups to create the HHS pandemic influenza plan and is represented on the National Vaccine Advisory Committee. CDC flu vaccine materials are part of VA’s annual flu campaign. CDC is currently engaged with the VA on various collaborations directed toward control and prevention of infectious diseases in general. For example, through the National Nosocomial Infections Surveillance (NNIS), selected VA hospitals have contributed data on bloodstream infections, surgical site infections, and other infectious events occurring during hospitalization. This information has been combined with data from over 300 additional hospitals to calculate national trends in healthcare-associated infections. Recently, efforts are underway to incorporate multiple VA hospitals into the National Healthcare Safety Network, a broader initiative to monitor healthcare-associated infections that incorporates NNIS. Additionally, through CDC’s Emerging Infections Program, VA hospitals contribute to regional surveillance systems that monitor various emerging pathogens and that determine the effectiveness of different public health interventions.
A component of the HHS Pandemic Influenza Plan is acquiring, distributing, and using antiviral drugs. CDC has been working to procure additional influenza countermeasures for the SNS. Because the H5N1 viruses isolated from people in Asia during the past two years appear resistant to the adamantine class of antiviral drugs but sensitive to the neuramidase inhibitor class of drugs such as oseltamivir (Tamiflu®), and zanamivir (Relenza®), the SNS has purchased enough oseltamivir (Tamiflu®) capsules to treat approximately 5.5 million adults and has oseltamivir (Tamiflu®) suspension to treat nearly 110,000 children. The SNS also includes 84,000 treatment regimens of zanamivir. With a goal to reach a national stockpile of 81 million treatment courses of Tamiflu by mid-2007, the President requested $1.03 billion for antiviral drug acquisition. WHO recently announced that the manufacturer of Tamiflu®, Roche, has donated three million adult courses. These will be available to WHO by mid-2006. Additional $400 million was requested in the FY06 HHS Budget Supplement for advanced development of new influenza antiviral drugs with broader and longer efficacy.
Enhancement of Quarantine Stations
CDC has statutory responsibility to make and enforce regulations necessary to prevent the introduction, transmission, or spread of communicable diseases from foreign countries into the United States. This effort includes maintaining quarantine stations. Quarantine stations respond to illness in arriving passengers, assure that the appropriate medical and/or procedural action is taken, and train Customs and Border Protection officers to watch for ill persons and imported items having public health significance. Currently, CDC’s Quarantine Stations are actively involved in pandemic influenza preparedness at their respective ports of entry. CDC's goal is to have a quarantine station in any port that admits over 1,000,000 passengers per year. We are expanding the nation’s Quarantine Stations; staff now have been selected for 18 Stations and are on duty at 17 of these Stations. HHS and the Department of Homeland Security (DHS) have recently established a Memorandum of Understanding setting out specific cooperation mechanisms to combat the introduction and spread of communicable diseases. These include DHS assistance with passive and, in certain instances, active surveillance of passengers arriving from overseas, as well as information sharing to assist in contact tracing of passengers with communicable or quarantinable diseases. HHS/CDC will provide training and other necessary support to prevent disease from entering the United States.
Informing the Public
Risk communication planning is critical to pandemic influenza preparedness and response. CDC is committed to the scientifically validated tenets of outbreak risk communication. It is vital that comprehensive information is shared across diverse audiences, information is tailored according to need, and information is consistent, frank, transparent, and timely. In the event of an influenza pandemic, clinicians are likely to detect the first cases; therefore messaging prior to a pandemic includes clinician education and discussions of risk factors linked to the likely sources of the outbreak, in addition to information targeted for specific groups, such as businesses and state and local officials. Given the likely surge in demand for healthcare, public communications must include instruction in assessing true emergencies, in providing essential home care for routine cases, and basic infection control advice. CDC provides the health-care and public health communities with timely notice of important trends or details necessary to support robust domestic surveillance. We also provide guidance for public messages through the news media, Internet sites, public forums, presentations, and responses to direct inquiries. This comprehensive risk-communication strategy can inform the nation about the medical, social, and economic implications of an influenza pandemic, including collaborations with the international community. We are working through the International Partnership on Avian and Pandemic Influenza and with the WHO Secretariat to harmonize our risk-communication messages as much as possible with our international partners, so that, in this world of a 24-hour news cycle, governments are not sending contradictory or confusing messages that will reverberate around the global to cause confusion.
Although much has been accomplished, from a public health standpoint more preparation is needed for a possible human influenza pandemic. As the President mentioned during the announcement of his National Strategy for Pandemic Influenza, our first line of defense is early detection. Because early detection means having more time to respond, it is critical for the United States to work with domestic and global partners to expand and strengthen the scope of early-warning surveillance activities used to detect the next pandemic.
Although the present avian influenza H5N1 strain in Southeast Asia does not yet have the capability of sustained person-to-person transmission, we are concerned that it could develop this capacity. CDC is closely monitoring the situation in collaboration with WHO, the affected countries, and other partners. We are using our extensive network with other federal agencies including VA, provider groups, non-profit organizations, vaccine and antiviral manufacturers and distributors, and state and local health departments to enhance pandemic influenza planning. The national response to the annual domestic influenza seasons provides a core foundation for how the nation will face and address pandemic influenza. We will continue to work with our partners, in implementing pandemic influenza preparedness efforts.
Thank you for the opportunity to share this information with you. I am happy to answer any questions.
Last Revised: December 16, 2005