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FDA Consumer
magazine
July-August 2003 Issue
By Carol Rados
From Texas to Taiwan, people are taking precautions to protect themselves from a virulent respiratory illness that is sweeping some areas of the globe as readily as the common cold. Severe acute respiratory syndrome (SARS)--which has killed hundreds of people and sickened thousands--is causing people to don face masks, avoid traveling, wash their hands constantly, and call their doctors at the first sign of a sniffle.
SARS was first recognized in February 2003 after a sudden outbreak of unexplained pneumonia that affected people in China and several other Asian countries. Symptoms included coughing, fever and shortness of breath. More than 700 SARS deaths in 29 countries had been reported to the World Health Organization (WHO) by the first week of June. In the United States, a handful of SARS cases and no deaths had been reported through early June, according to the Centers for Disease Control and Prevention (CDC).
So far, all of the SARS cases in the United States have been among travelers returning to this country from other parts of the world. Department of Health and Human Services Secretary Tommy G. Thompson says, "Cases in the United States have had relatively less severe manifestations of SARS compared to cases reported in other countries."
In general, early signs of a SARS infection include a fever greater than 100.4 F, headache, an overall feeling of discomfort, and body aches. Some people also experience mild respiratory symptoms. After two to seven days, people with SARS may develop a dry cough and have trouble breathing. In 10 percent to 20 percent of cases, patients require the use of a ventilator to help them breathe.
According to the CDC, SARS appears to be spread by close person-to-person contact. Potential ways include touching the skin of other people or objects that are contaminated with infectious droplets and then touching the eyes, nose, or mouth. Or the virus can be transmitted when someone who is sick with SARS coughs or sneezes droplets into the air and someone else breathes them in. It's also possible that SARS can be spread more broadly through the air, or by other ways that are currently unknown.
Recent results from WHO's Communicable Disease Surveillance and Response studies have produced the first scientific data on how long the SARS virus can live in various places and conditions. The results demonstrate that the microbe can linger outside an infected person's body for at least 24 hours.
However, CDC Director Julie L. Gerberding, M.D., M.P.H., says, "Finding a virus on a surface does not necessarily mean that surface has anything at all to do with transmitting the virus from one person to another." Thinking back to the early days of HIV infection, she says, "We had a lot of data coming out indicating that HIV could survive on tabletops for prolonged periods of time, but in fact, tabletops were not a mode of transmitting HIV from one person to another."
Gerberding adds that it's difficult to draw conclusions from experiments such as those that look at the longevity of microorganisms on environmental surfaces because the methods used vary.
Scientists at the CDC and elsewhere have unraveled the genetic code of a previously unrecognized coronavirus in patients with SARS. Coronaviruses [pictured below] have a halo or crown-like appearance under a microscope, and are a common cause of mild to moderate upper-respiratory illness in humans. In animals, coronaviruses are associated with respiratory, gastrointestinal, liver and neurologic disease. While the new coronavirus is the leading suspect for the microbe that causes SARS, other viruses are also under investigation as potential culprits.
Results of the first major epidemiological study of SARS, published in the May 24, 2003, issue of The Lancet, indicate that the average incubation period (time between infection and onset of symptoms) of SARS is estimated to be six to 10 days. The authors of the study stressed that reducing the time from the onset of symptoms to hospital quarantine is one of the most important public health measures that can be taken to reduce SARS transmission, and to potentially eradicate the disease.
In the absence of effective drugs or a vaccine for SARS, scientists are moving rapidly on multiple fronts to control the disease. Because there isn't yet a full understanding of the natural course of illness in someone infected with the SARS virus, the CDC says that it likely will take various government agencies and private organizations working together to halt its spread.
The Food and Drug Administration is carefully tracking the progress being made in defining, treating and, ultimately, defeating the SARS virus, to ensure that all the agency's resources are aggressively, safely, and smartly deployed. The FDA is committed to providing the prompt regulatory oversight needed to help defeat SARS as soon as possible.
The FDA is working closely with the CDC and the National Institutes of Health on the development of reliable diagnostic tools that will help identify the microbe responsible for SARS. One such experimental laboratory test already has been developed by the CDC. In addition, the FDA is ensuring that adequate supplies of various medical products will be available in the event of a broader spread of the disease in the United States.
The FDA's Center for Devices and Radiological Health is charged with guaranteeing the reliability of diagnostic tools. And the agency's Center for Drug Evaluation and Research is helping to identify drugs that may be effective in combating the agent that causes SARS. The Center for Biologics Evaluation and Research (CBER) is part of a team that is facilitating the development of several potential vaccines. CBER is working with other government agencies and the private sector to address many of the most difficult early issues in vaccine development.
The FDA has already approved dozens of tests for use in diagnosing different types of acute respiratory syndromes, and has put in place a postmarket surveillance program to measure how well those tests are working. The tests do not diagnose SARS; rather, they help to diagnose other conditions that may have symptoms similar to SARS. In this way, physicians can rule out SARS as a diagnosis.
Because so many organizations are working together on this important public health issue, the United States is now better ready to respond to any escalation of SARS cases.
The CDC says the best defense against SARS is frequent, thorough hand washing with soap and water. Contrary to what many people think about surgical masks for protection, the CDC does not recommend their routine use in public, stating that the masks are not 100 percent effective against the SARS virus. The CDC also advises against travel to certain areas worldwide. (See www.cdc.gov for up-to-date travel advisories.) Only when there are no additional cases of transmission within affected communities, says Gerberding, will there no longer be a need for travel advisories to those countries.
Anyone who experiences a fever greater than 100.4 F along with a cough or difficulty breathing should call a doctor. In addition, those coming in contact with others who have either the same symptoms or have traveled to SARS-affected areas are at increased risk of SARS. Many people infected with SARS, however, recover within a couple of weeks.
For updates on what's being done to combat SARS:
Food and Drug Administration
www.fda.gov/oc/opacom/hottopics/sars/
Centers for Disease Control and Prevention
www.cdc.gov/ncidod/sars/
National Institute of Allergy and Infectious Diseases
www.niaid.nih.gov/factsheets/sars.htm
World Health Organization
www.who.int/csr/sars/en/
At this time, it is not known whether severe acute respiratory syndrome (SARS) can be transmitted through blood. As a precaution, however, the Food and Drug Administration has issued guidance on prudent steps to safeguard the U.S. blood supply from SARS.
The FDA is taking this interim measure to protect the blood supply while more is learned about the disease. Highlights of the guidelines include:
The Food and Drug Administration and the Federal Trade Commission are warning Web site operators making claims or suggesting that their products will protect against, treat, or even cure severe acute respiratory syndrome (SARS) that it is against the law to make such claims in the absence of scientific evidence. No products have been found effective in preventing, treating or curing SARS. Operators are being warned to remove any misleading or deceptive claims from the Internet.
Consumers are being told to "hold on to your money."