LETTERS TO THE EDITOR Influenza A Outbreaks in Nursing Homes
To the Editor:-As discussed by Coles et al,’ a low rate of staff vaccination (10%) and failure to detect early staff cases and administer amantadine prophylaxis may have contributed to the influenza outbreak in a well immunized nursing home population. We describe another New York nursing home influenza A outbreak’ in which low rates of both staff vaccination and amantadine use may have been contributing factors. Unlike what occurred in the 1987-1988 influenza season, the predominant circulating virus and vaccine components in 1991-1992 were antigenically similar; thus antigenic drift is less likely as an explanation of our outbreak. During December 1991 and January 1992, 65 residents of a 362-bed nursing home developed influenza-like illness; 34 (52%)developed pneumonia, 19 (29%)required hospitalization, and two died. From mid-October through mid-November 1991, 295 (88%) of the residents had received influenza vaccine. The calculated vaccine efficacy (VE) for preventing influenza-like illness and pneumonia in the residents was 43% (95% confidence interval [CI] = 5%,66%)and 45% (95% CI = -18%,74%), respectively. Questionnaires were distributed to nursing home employees with patient contact to determine the vaccination coverage and incidence of influenza-like illness among these staff. Of 339 employees who completed questionnaires, only 33 (10%) had been vaccinated in the fall before or during the outbreak; the calculated VE for preventing influenza-like illness in the employees was 86% (95% CI = 34%,99%). Similar to Coles’ outbreak, several staff members reported onset of influenza-like illness preceding the onset of illness in the residents (Figure l), suggesting employees may have introduced influenza into the nursing home. Amantadine was not routinely prescribed for staff or residents. Given the relatively high calculated VE for nursing home employees who received influenza vaccine in our investigation, we support efforts to increase vaccine coverage for all health-care workers and others in close contact with highrisk persons to reduce the risk of transmission. One approach would be to require influenza vaccination for health-care 15 -n
0 Employees I 0 Residents I
:I 12 11
R
4
3 2 l0 1 l a11
12/5 , 1219
Date of Onset December 1991
January 1992
FIGURE 1. Influenza-like illness (characterized by fever 2 100°F (238OC)with cough or sore throat) among residents and employees of a nursing home by date of onset: New York, Dec. 1, 1991-January 10, 1992. IAGS 40:1288-1289, 1992 0 1992 by the American Geriatrics Society
workers in nursing homes; proof that health-care workers are immune to measles and rubella is already required for hospitals in New York State.3In addition, increased use of amantadine for both ill employees and residents may be useful in controlling influenza A outbreaks in nursing home populations. ROBINM. IKEDA,MD New York State Dept. of Health Albany, NY and Epidemiology Program Office Centers for Disease Control PETER D. DRABKIN, MPH GUTHRIE S. BIRKHEAD,MD, MPH New York State Dept. of Health Albany, NY REFERENCES 1. Coles FB, Balzano GJ, Morse DL. An outbreak of Influenza A (H3N2) in a well immunized nursing home population. J Am Geriatr Soc
1992;40:589-592. 2. CDC. Outbreak of Influenza A in a Nursing Home-New York, December 1991-January 1992. MMWR 1992;41:129-131. 3 . Part 405, Title 10. Official Compilation of Codes, Rules and Regulations of the State of New York.
Rhabdomyolysis and the Neuroleptic Malignant Syndrome To the Editor:-The paper by Marcus et all is a valuable reminder of the importance of considering rhabdomyolysis in elderly patients who have been immobilized. However, although their exclusion criteria for a raised creatine kinase (CK) included hypothyroidism, myocardial infarction, injuries, surgery, and intra-muscular injections, there is one further cause of a raised creatine phosphokinase which may be occult in elderly patients. Neuroleptic malignant syndrome (NMS) may cause both immobility and a raised CK and occurs in about 1% of hospitalized psychiatric patients and in an as yet undetermined number of medical patients. Although usually associated with neuroleptic medications, NMS has also been reported with metoclopramide.’ Its presence in ill elderly patients may not be noted in the presence of a proven infection3 Dehydration, infection, and physical exhaustion may precipitate NMS4: some of these elements were present in almost all of the patients in Marcus’ study. In many cases it is a relatively benign illness if detected early and responds to supportive measures similar to those given to an elderly patient with an i n f e ~ t i o n .In ~ good geriatric medical practice, it is likely that the offending medication, usually a neuroleptic, will be stopped at admission of a sick, immobile patient. It may be difficult to detect NMS in a retrospective study: history-taking is unreliable at detecting psychotropic drug use in the e l d e r l ~ .The ~ presence of other illnesses and medications may contribute to misinterpretation of the clinical information6; extra-pyramidal symptomatology may mimic other conditions, and the immobility, autonomic dysfunction and pyrexia may have other causes. A prospective study may help to clarify whether an NMS reaction to agents with central dopamine agonist properties is the cause of
0002-8614/92/$3.50
To the Editor:-As discussed by Coles et al,’ a low rate of staff vaccination (10%) and failure to detect early staff cases and administer amantadine prophylaxis may have contributed to the influenza outbreak in a well immunized nursing home population. We describe another New York nursing home influenza A outbreak’ in which low rates of both staff vaccination and amantadine use may have been contributing factors. Unlike what occurred in the 1987-1988 influenza season, the predominant circulating virus and vaccine components in 1991-1992 were antigenically similar; thus antigenic drift is less likely as an explanation of our outbreak. During December 1991 and January 1992, 65 residents of a 362-bed nursing home developed influenza-like illness; 34 (52%)developed pneumonia, 19 (29%)required hospitalization, and two died. From mid-October through mid-November 1991, 295 (88%) of the residents had received influenza vaccine. The calculated vaccine efficacy (VE) for preventing influenza-like illness and pneumonia in the residents was 43% (95% confidence interval [CI] = 5%,66%)and 45% (95% CI = -18%,74%), respectively. Questionnaires were distributed to nursing home employees with patient contact to determine the vaccination coverage and incidence of influenza-like illness among these staff. Of 339 employees who completed questionnaires, only 33 (10%) had been vaccinated in the fall before or during the outbreak; the calculated VE for preventing influenza-like illness in the employees was 86% (95% CI = 34%,99%). Similar to Coles’ outbreak, several staff members reported onset of influenza-like illness preceding the onset of illness in the residents (Figure l), suggesting employees may have introduced influenza into the nursing home. Amantadine was not routinely prescribed for staff or residents. Given the relatively high calculated VE for nursing home employees who received influenza vaccine in our investigation, we support efforts to increase vaccine coverage for all health-care workers and others in close contact with highrisk persons to reduce the risk of transmission. One approach would be to require influenza vaccination for health-care 15 -n
0 Employees I 0 Residents I
:I 12 11
R
4
3 2 l0 1 l a11
12/5 , 1219
Date of Onset December 1991
January 1992
FIGURE 1. Influenza-like illness (characterized by fever 2 100°F (238OC)with cough or sore throat) among residents and employees of a nursing home by date of onset: New York, Dec. 1, 1991-January 10, 1992. IAGS 40:1288-1289, 1992 0 1992 by the American Geriatrics Society
workers in nursing homes; proof that health-care workers are immune to measles and rubella is already required for hospitals in New York State.3In addition, increased use of amantadine for both ill employees and residents may be useful in controlling influenza A outbreaks in nursing home populations. ROBINM. IKEDA,MD New York State Dept. of Health Albany, NY and Epidemiology Program Office Centers for Disease Control PETER D. DRABKIN, MPH GUTHRIE S. BIRKHEAD,MD, MPH New York State Dept. of Health Albany, NY REFERENCES 1. Coles FB, Balzano GJ, Morse DL. An outbreak of Influenza A (H3N2) in a well immunized nursing home population. J Am Geriatr Soc
1992;40:589-592. 2. CDC. Outbreak of Influenza A in a Nursing Home-New York, December 1991-January 1992. MMWR 1992;41:129-131. 3 . Part 405, Title 10. Official Compilation of Codes, Rules and Regulations of the State of New York.
Rhabdomyolysis and the Neuroleptic Malignant Syndrome To the Editor:-The paper by Marcus et all is a valuable reminder of the importance of considering rhabdomyolysis in elderly patients who have been immobilized. However, although their exclusion criteria for a raised creatine kinase (CK) included hypothyroidism, myocardial infarction, injuries, surgery, and intra-muscular injections, there is one further cause of a raised creatine phosphokinase which may be occult in elderly patients. Neuroleptic malignant syndrome (NMS) may cause both immobility and a raised CK and occurs in about 1% of hospitalized psychiatric patients and in an as yet undetermined number of medical patients. Although usually associated with neuroleptic medications, NMS has also been reported with metoclopramide.’ Its presence in ill elderly patients may not be noted in the presence of a proven infection3 Dehydration, infection, and physical exhaustion may precipitate NMS4: some of these elements were present in almost all of the patients in Marcus’ study. In many cases it is a relatively benign illness if detected early and responds to supportive measures similar to those given to an elderly patient with an i n f e ~ t i o n .In ~ good geriatric medical practice, it is likely that the offending medication, usually a neuroleptic, will be stopped at admission of a sick, immobile patient. It may be difficult to detect NMS in a retrospective study: history-taking is unreliable at detecting psychotropic drug use in the e l d e r l ~ .The ~ presence of other illnesses and medications may contribute to misinterpretation of the clinical information6; extra-pyramidal symptomatology may mimic other conditions, and the immobility, autonomic dysfunction and pyrexia may have other causes. A prospective study may help to clarify whether an NMS reaction to agents with central dopamine agonist properties is the cause of
0002-8614/92/$3.50
