Target surveillance, drop unproven practices in LTC

Efficacy of flu vaccinations remains controversial

Infection control professionals working in hospital-affiliated or free-standing long-term care settings should cease facilitywide, total surveillance efforts in favor of targeted or "surveillance by objective" approaches, a clinician advised recently in St. Louis at the annual conference of the Society for Healthcare Epidemiology of America.

"The bottom line is that [ICPs] in many of these facilities are being pushed to do total surveillance. They are doing their best, but they just don’t have the resources," said Allison McGeer, MD, director of infection control at Mount Sinai and Princess Margaret Hospitals in Toronto. "We need to be moving in long-term care as we have in acute care to something like surveillance by objectives, where you pick the things that are most relevant to your setting and you look at those for a period of time."

The most common infection with the largest impact in long-term care settings is respiratory tract infection, but ICPs also could target process indicators like vaccination rates for surveillance, she noted.

"You don’t really need calculated, analyzed surveillance data to tell you whether there is a problem in your nursing home," McGeer told SHEA attendees. "What you need is the people in the trenches in your nursing home being able to tell you whether there is a problem."

In facilities where ICPs only work part time, for example, health care aides and licensed practical nurses working with residents and patients should be trained to report clusters of infections, she said.

"We need to develop systems where health care aides and LPNs have the ability to say, ‘We have three people with respiratory tract infections this week. I need to call the ICP now and not just write it down on a piece of paper,’" McGeer advised.

Though plagued by a dearth of data, the efficacy — or lack thereof — of a variety of infection control strategies in long-term and chronic care facilities is starting to become clear, another clinician reported at the same SHEA session.

On one hand, such practices as using disposable thermometers to prevent Clostridium difficile outbreaks or enacting enteric precautions to curtail outbreaks of gastroenteritis are proven efficacious, says Larry Strausbaugh, MD, hospital epidemiologist at the Portland (OR) VA Medical Center, which has an affiliated nursing home care unit.

On the other hand, infection control strategies that have shown little value in long-term and chronic care settings include routine changes of percutaneous feeding tubes, which feed directly into the gastrointestinal tract. A study published last year revealed there were no observed differences in clinical outcomes in long-term care patients when feeding tubes were changed only as necessary, rather than routine monthly changes.1

Likewise, Strausbaugh reported the results of a study he conducted with colleagues that showed the futility of attempting to decolonize long-term care residents for methicillin-resistant Staphylococcus aureus in the medical center’s 120-bed nursing home care unit .2

"We were intent on eradicating MRSA from our facility and we treated all of our carriers," he told SHEA attendees. "Overall, 56% of these efforts failed either on the basis of persistently positive MRSA cultures or [due to] relapse of MRSA colonization. . . . I think in general it is a bad idea unless you are confronting an active outbreak with lots of symptomatic cases."

Infection control strategies that show conflicting data on efficacy are less clear-cut. Surprisingly, influenza vaccination of long-term care residents and patients has become one of these questioned strategies, he reported.

"I know it is almost heretical in this audience to put influenza vaccination in this category, and I did it with great care," Strausbaugh said. "I am a believer and I do vaccinate all of our long-term care residents every year for influenza and plan to keep doing so. But there certainly is some remaining controversy in the literature."

Those controversial data include a report of an outbreak of influenza A that occurred on a 37-bed unit of a five-ward chronic care facility, he said.3 The authors reported that even though 92% of the residents had been recently immunized, there was a 28% attack rate of influenza A, and six out of the 11 cases who contracted it died.

"Rather disheartening," Strausbaugh said. "[And] from the virologic evidence given, it appears that there was a good match between the vaccine used in these individuals and the strain that was floating amongst these patients."

Indeed, in the report cited, the authors concluded that they documented little protective effect of the vaccine. Though "some nursing home outbreak reports demonstrate at least partial vaccine protection . . . vaccine efficacy has been poor or nonexistent in many others."

On the other hand, a meta-analysis of some 20 studies found that morbidity and mortality are significantly reduced when influenza vaccine is administered before an epidemic if the vaccine strain is identical or similar to the epidemic strain.4 However, vaccine efficacy can be expected to vary if the epidemic strain is different from the vaccine strain, though the authors still documented efficacy unless there was antigenic "shift" in the circulating virus that effectively canceled out all protective effects of the vaccine.

"They found 20 observational studies from the literature with a cohort design involving vaccinated persons and unvaccinated persons and looked at these for end points," Strausbaugh told SHEA attendees. "I think this is very compelling in terms of favoring vaccination in this population."

References

1. Graham S, Sim G, Laughren R, et al. Percutaneous feeding tube changes in long-term-care facility patients. Infect Control Hosp Epidemiol 1996; 17:732-736.

2. Strausbaugh LJ, Jacobson C, Sewell DL, et al. Antimicrobial therapy for methicillin-resistant Staphylococcus aureus colonization in residents and staff of a veterans affairs nursing home care unit. Infect Control Hosp Epidemiol 1992; 13:151-159.

3. Morens DA, Rash VM. Lessons from a nursing home outbreak of influenza A. Infect Control Hosp Epidemiol 1995; 16:275-280.

4. Gross PA, Hermogenes AW, Sacks HS, et al. The efficacy of influenza vaccine in elderly persons: A meta-analysis and review of the literature. Ann Intern Med 1995; 123:518-527.