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Alfred Sommer, MD, MHS
SARS (severe acute respiratory syndrome) has “pride of place” as this issue’s cover article. The epidemic, which engaged the School’s faculty, students, and alumni, offered myriad lessons on which to reflect.
Frightening new infectious diseases and global pandemics are not just things of the past. New microbial threats remain very much a part of our modern world, even as we’ve become numbingly complacent about the horrific suffering and loss of life exacted by HIV/AIDS, tuberculosis, and malaria, year in and year out.
Microbial threats need not be malignantly inspired. Indeed, they rarely have been.
SARS, like swine flu, HIV/AIDS, Ebola, and “mad cow disease” before it, probably arose from subtle alterations in the genetic code of a virus that had previously been confined to other species or had harmlessly co-existed with man. Either pre-existing gene(s) mutated, or related viruses of other species swapped genetic material, posing a new threat to human health. There is no reason to believe these laws of nature will be repealed anytime soon, or that increasing urbanization, with its encroachment on wildlife habitats and the growing proximity between man and beast, will do anything but facilitate these processes and increase our risk.
Once a virus infects humans, and humans become contagious, the virus will circle the globe at the speed of human movement. The “Spanish” flu pandemic of 1918/1919 required steamships to cross oceans, and still killed over 20 million people worldwide. Case for case, SARS is five times more lethal, and crossed oceans at jet speed. But to date, it has been far less contagious. The 8,100 cases and 774 deaths were largely confined to China, Hong Kong, Taiwan, and Singapore. But it only took one initial case, probably in China’s southeast province of Guangdong, to seed all the others. It also took only one case to establish Toronto’s epidemic, straining its health care system and decimating its globally dependent economy.
We were at the mercy of SARS in the same ways our ancestors were at the mercy of “Spanish” flu, the Black Death, polio, and smallpox. We have no vaccine to protect us from SARS and no drug with which to effectively treat it. This is a scary and unusual experience for a society that takes for granted an unending flow of miracle medicinals.
Epidemics are prevented and contained by diligently executing the most basic of public health strategies: Identify the causal agent (in this instance, a specific coronavirus); determine its mode of spread (primarily close contact with someone already sick from SARS); and break the chain of transmission (quickly identify and quarantine all SARS patients and their contacts—and, should a contact become ill, quarantine the contact’s contacts). Because SARS patients became ill and went to hospitals at about the time they first became infectious, hospital-acquired infections accounted for the vast majority of cases.
Travel to infected locales dropped precipitously. This wasn’t panic, merely heightened good sense.
The more people knew about the disease, and the more they trusted their government’s public health interventions, the calmer and more cooperative they became. Reports in the U.S. were timely and accurate; “risk communication,” always a difficult job, placed SARS in perspective. China suffered the most disease and the greatest unrest precisely because of the government’s poor initial response.
It is too early to compose SARS’ epitaph. Public health interventions helped contain the epidemic, but the nature of the epidemic lent itself to control. It will be months (if not years) before we can be certain SARS is truly gone.
New microbial threats, like bad movies, premier at regular intervals. Since 9/11, I no longer need to explain what “public health” is, or why the School’s mission is crucial. But that is only true for unexpected attacks by dangerous microbes (anthrax, smallpox, SARS). The public still needs to be reminded that the real threats to life are recurrent infectious diseases for which people fail to obtain available immunizations (flu, which kills 36,000 Americans each year); chronic infections that kill millions of people every year (HIV/AIDS, malaria, tuberculosis); and the noninfectious epidemics (obesity, cancer, and coronary artery disease) that now account for most deaths in the United States.