Unanswered questions make SARS an occupational health concern
Health care workers at risk, perhaps other employees as well
One of the nagging issues surrounding the newly identified disease severe acute respiratory syndrome (SARS) is that so many questions remain unanswered. Health care workers clearly are at risk, as has been demonstrated in several countries, but what about workers in general? Is it a broader occupational health concern? Does the relatively small number of cases in the United States mean we’ve stopped the disease in its tracks?
The Atlanta-based Centers for Disease Control and Prevention (CDC) has warned that we shouldn’t stop worrying just yet. "One of the really important messages that we’re emphasizing to the public health community today is that despite the fact that we do seem to be able to contain the spread of this disease in the United States, we have to remain vigilant because it [only takes ] one highly transmittable patient [to] infect a very large number of people," Julie Gerberding, MD, CDC director, said in an April 17 update.
In the United States, local transmission of suspected SARS has been limited to health care workers and close contacts of suspected SARS patients who were travelers.
"By and large, the occupational medicine issues are issues of medical centers," asserts Mark Russi, MD, MPH, associate professor at Yale-New Haven (CT) Hospital, director of occupational health and chair of the Arlington Heights, IL-based American College of Occupational and Environmental Medicine’s (ACOEM) Occupational and Environmental Infectious Disease Committee.
"In terms of health care workers, their probability of getting exposed is most likely the workplace," adds Jean Randolph, RN, COHN-S, a member of the Board of the Atlanta-based American Association of Occupational Health Nurses (AAOHN). "A person comes in who is real sick may not have been at work for a couple of days, and they need someone to take care of them. When you think of a health care worker seeing someone like that come to the door with what appears to be a cold or bronchitis, the reality is they will normally not wear a mask. They never catch things like colds from patients — you appear to develop an immune status. So we have this mentality that we’re not going to catch anything."
With SARS, of course, all that has changed. "I think they weren’t [wearing their masks at first] but I believe they are now," Randolph says. "One of the reasons they’ve become sensitized to it is precisely because they are health care workers. The message is coming home pretty quickly from infection control people, and their index of suspicion is way higher. The first thing they say to people with respiratory problems now is, Have you been out of the country?’"
This is a good thing, says Randolph — not just because of SARS, but because, she says, health care workers may be less cavalier about self-protection in general. "This may serve to be that wake-up call we need," she says. "You have to take care of yourself. It can happen to you."
What about other workers?
Occupational health professionals may well yet see SARS in workplaces outside of health care, says Randolph.
One possible means of transmission to the general working population, she offers, could be adoptions. "We have people within organizations who are adopting children, and may, for example, have gone to China to pick up a child and stayed there for four to six weeks. That long ago, we didn’t have the same profile on this disease. So they find themselves in a country where SARS is running rampant, and they didn’t know about it."
Or workers may have planned trips and left before that much was known about the disease, says Randolph. "My basic recommendation is if someone has come back to work after a vacation or after picking up an adopted child, you need to ask them to report to employee health before they go back to work, and check their temperature twice a day. I would also tell the health care professionals that when they are in direct patient contact, you would appreciate it if they wore a mask. We don’t know how it’s spread — whether it’s communicable."
What we don’t know . . .
Randolph’s last comment is right on the money, says Russi — there is much we still don’t know about SARS. "There’s a lot of investigation going on as to whether the spread is just through droplets or whether it’s airborne," he observes. "Droplet spread takes place within three to six feet. But certain diseases are spread through the airborne route — such as coughs. They can float their way up through HVAC [heating, ventilating, and air conditioning] systems and infect people within a much wider range. The answer to this question really isn’t known. Also, researchers are investigating whether objects like doorknobs can be contaminated through touch. We think it can get into the blood and that’s a possibility, although I’d be surprised if it emerged as major route of transmission; there’s apparently one scientist in WHO [Geneva-based World Health Organization] who said that at least an incomplete version of the virus can be cultured out from the stool; but we’re concerned most about the respiratory system."
All of that said, the precautions currently in place at hospitals and health care institutions are broader than what would be required to protect against droplet transmission. "They are instructed to use HEPA respiratory filters and gowning, gloving, and air protections. This is designed to be protective against a number of modes of transmission," notes Russi. "We hope those will be effective."
This may be part of the reason that the outbreak has so far been much less severe in the United States. "It’s a little hard to say," he observes. "It’s probably largely attributed to the fact that the [index case individual] traveled to Toronto before we knew much about SARS."
Other questions still remain, he adds, such as concerns about so-called super-spreaders — people who are capable of transmitting the disease much more easily than the average individual. "Those are some of the unknowns," Russi sums up. "Why our experience differs so much from Canada is probably largely due to the fact that they were unlucky enough to have the index case early on, before screening mechanisms were put in. Anyone put in the hospital now with respiratory symptoms has to be asked questions about travel."
As long as health care professionals can recognize the individual who possibly has SARS based on symptoms and travel history, "I think we have the ability to deal with airborne contact," says Russi. "The trick is recognizing it. This may be more difficult if the epidemic keeps spreading and it becomes a more global phenomenon; then, it may not be as predictive to ask where you have been."
Researchers hope to develop more effective diagnostic tests than are currently available, he adds. "For example, PCR [polymerase chain reaction] tests become positive earlier than indirect immunofluorescent antibody tests [which are technically difficult to do, and are not positive until about 10 days], but there have been a number of false negatives," Russi notes.
Because of all of the aforementioned unknowns, this is not the time, he concludes, for occupational health professionals to relax. The bottom line, he says, is that "it is not time yet to breathe a sigh of relief and say we’ve dodged the bullet."
[For more information, contact:
- Mark Russi, MD, MPH, Associate Professor, Medicine and Public Health, Director of Occupational Health, Yale-New Haven Hospital, 20 York St., New Haven, CT 06504. Telephone: (203) 688-5203.
- Jean Randolph, RN, COHN-S, American Association of Occupational Health Nurses. Telephone: (404) 906-5126.]