April 7, 2003
Good morning, Mr. Chairman and Members of the Committee. I am Dr. Julie L. Gerberding, Director, Centers for Disease Control and Prevention (CDC). Thank you for the invitation to participate today in this timely hearing on a critical public health issue: severe acute respiratory syndrome (SARS). I will update you on the status of the spread of this emerging global microbial threat and on CDC's response with the World Health Organization (WHO) and other domestic and international partners.
As we have seen recently, infectious diseases are a continuing threat to our nation's health. Although some diseases have been conquered by modern advances, such as antibiotics and vaccines, new ones are constantly emerging, such as Legionnaires' disease, Lyme disease, and hantavirus pulmonary syndrome. SARS is the most recent reminder that we must always be prepared for the unexpected. SARS also highlights that U.S. health and global health are inextricably linked and that fulfilling CDC's domestic mission–to protect the health of the U.S. population–requires global awareness and collaboration with international partners to prevent the emergence and spread of infectious diseases.
Emergence of SARS
Since late February 2003, CDC has been supporting WHO in the investigation of a multi-country outbreak of unexplained atypical pneumonia referred to as severe acute respiratory syndrome (SARS). As of April 3, 2003, a total of 2300 probable or suspected cases of SARS have been reported to WHO from 16 countries, and 79 of these patients have died. This includes 115 suspected cases in the United States, from 29 states. None of the suspected cases in the United States have died.
In February, the Chinese Ministry of Health notified WHO that 305 cases of acute respiratory syndrome of unknown etiology had occurred in Guangdong province in southern China since November 2002. In February 2003, a man who had traveled in mainland China and Hong Kong became ill with a respiratory illness and was hospitalized shortly after arriving in Hanoi, Vietnam. Health-care providers at the hospital in Hanoi subsequently developed a similar illness. During late February, an outbreak of a similar respiratory illness was reported in Hong Kong among workers at a hospital; this cluster of illnesses was linked to a patient who had traveled previously to southern China. On March 12, WHO issued a global alert about the outbreak and instituted worldwide surveillance for this syndrome, characterized by fever and respiratory symptoms.
On Friday, March 14, CDC activated its Emergency Operations Center (EOC) in response to reports of increasing numbers of cases of SARS in several countries. On Saturday, March 15, CDC issued an interim guidance for state and local health departments to initiate enhanced domestic surveillance for SARS; a health alert to hospitals and clinicians about SARS; and a travel advisory suggesting that persons considering nonessential travel to Hong Kong, Guangdong, or Hanoi consider postponing their travel. HHS Secretary Tommy Thompson and I conducted a telebriefing to inform the media about SARS developments.
Of the 115 reported suspected cases among U.S. residents, 109 have traveled to mainland China, Hong Kong, Singapore, or Hanoi, Vietnam, 4 had household contact with a suspected case, and 2 are healthcare workers who provided medical care to a suspected case. Cases in the United States have had relatively less severe manifestations of SARS, compared to cases reported in other countries. Forty-three cases have been hospitalized. As of April 3, 12 remain in the hospital, and none have died. Community transmission of SARS has not been identified within the United States. Transmission to healthcare workers has only been observed in one cluster involving two healthcare workers in the United States, in contrast to the numerous instances of possible transmission to healthcare workers that have been reported in several other countries.
Cases of SARS continue to be reported from around the world. The disease is still primarily limited to travelers to Hong Kong, Hanoi, Singapore, and mainland China; to health care personnel who have taken care of SARS patients; and to close contacts of SARS patients. Based on what we know to date, we believe that the major mode of transmission is through droplet spread when an infected person coughs or sneezes. However, we are concerned about the possibility of airborne transmission and also the possibility that objects that become contaminated in the environment could serve as modes of spread.
CDC Response to SARS
CDC continues to work with WHO and other national and international partners to investigate this ongoing emerging global microbial threat. This is a major challenge, but it is also an excellent illustration of the intense spirit of collaboration among the global scientific community to combat a global epidemic.
CDC is participating on teams assisting in the investigation in mainland China, Hong Kong, Taiwan, Thailand, and Vietnam. In the United States, we are conducting active surveillance and implementing preventive measures, working with numerous clinical and public health partners at state and local levels. As part of the WHO-led international response thus far, CDC has deployed approximately 30 scientists and other public health professionals internationally and has assigned almost 300 staff in Atlanta and around the United States to work on the SARS investigation.
CDC has issued interim guidance to protect against spread of this virus for close contacts of SARS patients, including in health care settings or in the home. We have also issued interim guidance for management of exposures to SARS and for cleaning airplanes that have carried a passenger with suspected SARS. We have issued travel advisories and health alert notices, which are being distributed to people returning from China, Hong Kong, Singapore, and Vietnam. We have distributed more than 200,000 health alert notice cards to airline passengers entering the United States from these areas, alerting passengers that they may have been exposed to SARS, should monitor their health for 10 days, and if they develop fever or respiratory symptoms, they should contact a physician.
WHO is coordinating daily communication between CDC laboratory scientists and scientists from laboratories in Asia, Europe, and elsewhere to share findings, which they are posting on a secure Internet site so that they can all learn from each other's work. They are exchanging reagents and sharing specimens and tissues to conduct additional testing. Our evidence and that of many of our partners indicates that a new coronavirus is the leading candidate for the cause of this infection.
Initial laboratory efforts were focused on a diagnosis based on clinical symptoms and available epidemiologic information. On the basis of this initial diagnosis, CDC used classical microbiologic approaches and molecular diagnostic methods to identify the agent or agents involved. A broad range of pathogens primarily associated with respiratory disease and for which respiratory symptoms might be secondary were targeted for detection in SARS specimens. Various methods were used for detection, including light and electron microscopy, immunohistochemistry, cell culture isolation techniques, serology, and other modern molecular techniques. An apparently new coronavirus was isolated in cell cultures, and coronavirus nucleotide sequences specific to this virus were detected in diseased tissues. This finding, coupled with the increasing reports that many WHO collaborating laboratories have detected this virus in specimens from SARS patients, suggests that this coronavirus is involved in the etiology of the disease. Efforts to further characterize the role of this coronavirus in SARS are ongoing at CDC and in other laboratories.
Rapid and accurate communications are crucial to ensure a prompt and coordinated response to any infectious disease outbreak. Thus, strengthening communication among clinicians, emergency rooms, infection control practitioners, hospitals, pharmaceutical companies, and public health personnel has been of paramount importance to CDC for some time. In the past three weeks, CDC has had multiple teleconferences with state health officials to provide them the latest information on SARS spread, implementation of enhanced surveillance, and infection control guidelines and to solicit their input in the development of these measures and processes. On Friday, April 4, WHO sponsored, with CDC support, a clinical video conference broadcast globally to discuss the latest findings of the outbreak and prevention of transmission in healthcare settings. The faculty was comprised of representatives from WHO, CDC, and several affected countries who reported their experiences with SARS. The video cast is now available on-line for download. Secretary Thompson and I, as well as other senior scientists and leading experts at CDC, have held numerous media telebriefings to provide updated information on SARS cases, laboratory and surveillance findings, and prevention measures. CDC is keeping its website current, with multiple postings daily providing clinical guidelines, prevention recommendations, and information for the public.
Currently, CDC is recommending that persons postpone non-essential travel to mainland China, Hong Kong, Singapore, and Hanoi, Vietnam. Persons who have traveled to affected areas and experience symptoms characteristic of SARS should contact a physician. Health care facilities and other institutional settings should implement infection control guidelines that are available on CDC's website.
We know that individuals with SARS can be very infectious during the symptomatic phase of the illness. However, we do not know how long the period of contagion lasts once they recover from the illness, and we do not know whether or not they can spread the virus before they experience symptoms. The information our epidemiologists have suggests that the period of contagion may begin with the onset of the very earliest symptoms of a viral infection, so our guidance is based on this assumption. SARS patients who are either being cared for in the home or who have been released from the hospital or other health care settings and are residing at home should limit their activities to the home. They should not go to work, school, or other public places until at least ten days after they are fully asymptomatic.
If a SARS patient is coughing or sneezing, he should use common-sense precautions such as covering his mouth with a tissue, and, if possible and medically appropriate, wearing a surgical mask to reduce the possibility of droplet transmission to others in the household. It is very important for SARS patients and those who come in contact with them to use good hand hygiene: washing hands with soap and water or using an alcohol-based hand rub frequently and after any contact with body fluids.
For people who are living in a home with SARS patients, and who are otherwise well, there is no reason to limit activities currently. The experience in the United States has not demonstrated spread of SARS from household contacts into the community. Contacts with SARS patients must be alert to the earliest symptom of a respiratory illness, including fatigue, headache or fever, and the beginnings of an upper respiratory tract infection, and they should contact a medical provider if they experience any symptoms.
Emerging Global Microbial Threats
Since 1994, CDC has been engaged in a nationwide effort to revitalize national capacity to protect the public from infectious diseases. Progress continues to be made in the areas of disease surveillance and outbreak response; applied research; prevention and control; and infrastructure-building and training. However, SARS provides striking evidence that a disease that emerges or reemerges anywhere in the world can spread far and wide. It is not possible to adequately protect the health of our nation without addressing infectious disease problems that are occurring elsewhere in the world.
Last month, the Institute of Medicine (IOM) published a report describing the spectrum of microbial threats to national and global health, factors affecting their emergence or resurgence, and measures needed to address them effectively. The report, Microbial Threats to Health: Emergence, Detection, and Response, serves as a successor to the 1992 landmark IOM report Emerging Infections: Microbial Threats to Health in the United States, which provided a wake-up call on the risk of infectious diseases to national security and the need to rebuild the nation's public health infrastructure. The recommendations in the 1992 report have served as a framework for CDC's infectious disease programs for the last decade, both with respect to its goals and targeted issues and populations. Although much progress has been made, especially in the areas of strengthened surveillance and laboratory capacity, much remains to be done. The new report clearly indicates the need for increased capacity of the United States to detect and respond to national and global microbial threats, both naturally occurring and intentionally inflicted, and provides recommendations for specific public health actions to meet these needs. The emergence of SARS, a previously unrecognized microbial threat, has provided a strong reminder of the threat posed by emerging infectious diseases.
The SARS experience reinforces the need to strengthen global surveillance, to have prompt reporting, and to have this reporting linked to adequate and sophisticated diagnostic laboratory capacity. It underscores the need for strong global public health systems, robust health service infrastructures, and expertise that can be mobilized quickly across national boundaries to mirror disease movements. As CDC carries out its plans to strengthen the nation's public health infrastructure, we will collaborate with state and local health departments, academic centers and other federal agencies, health care providers and health care networks, international organizations, and other partners. We have made substantial progress to date in enhancing the nation's capability to detect and respond to an infectious disease outbreak; however, the emergence of SARS has reminded us yet again that we must not become complacent. We must continue to strengthen the public health systems and improve linkages with domestic and global colleagues. Priorities include strengthened public health laboratory capacity; increased surveillance and outbreak investigation capacity; education and training for clinical and public health professionals at the federal, state, and local levels; and communication of health information and prevention strategies to the public. A strong and flexible public health infrastructure is the best defense against any disease outbreak.
Thank you very much for your attention. I will be happy to answer any questions you may have.
Last Revised: April 7, 2003