Acute upper respiratory tract viral illness and influenza immunization in homes for the elderly

Abstract

SUMMARYOccupants of 482 long-stay and 33 short-stay beds in 11 Leicester City Council homes for the elderly were studied during a 30-week period from September 1988 to March 1989 to determine the incidence, aetiology, morbidity, and mortality of acute upper respiratory tract viral infections and the use of influenza vaccine.Influenza immunization rates by home ranged from 15·4 to 90% (mean 45%). There were no differences in the distribution of medical conditions by home. The highest immunization rates were seen in people with chest disease (77%), heart disease (60%), diabetes (56%), and those with three medical conditions (75%). There was an average of 0·7 upper respiratory episodes per bed per annum with a mortality of 3·4% (6/179). Half of all episodes were seen by a general medical practitioner and 81 of 90 (90%) referrals were prescribed antibiotics costing approximately £7.50 per patient. Lower respiratory tract complications developed during 45 (25%) of 179 episodes including 3 of 12 coronavirus infections, 3 of 9 respiratory syncytial virus infections, 2 of 4 adenovirus infections, 1 of 11 rhinovirus infections, but none of 5 influenza infections. Respiratory infections were caused mostly by pathogens other than influenza virus during the influenza period documented nationally. This highlights the role of coronaviruses, respiratory syncytial virus, and unidentified agents in the elderly, and questions the assumptions made in American estimates on the impact of influenza and the value of influenza vaccines.

Impact of influenza and respiratory syncytial virus on mortality in England and Wales from January 1975 to December 1990

“…In the elderly RSV can produce a 'flu-like syndrome indistinguishable from influenza and is known to cause a high incidence of pneumonia and death [6][7][8][9][10][11][12][13][14]. The estimates provided by the present analysis indicate that RSV gives rise to considerable mortality in England and Wales causing 60-80% more deaths than influenza, i.e., a predicted 22000-23000 deaths each winter.…”

“…Laboratory reports of influenza have not been used in previous publications suggesting that they may provide a poor quantitative index of influenzal mortality. However, influenza and RSV are clinically indistinguishable in the elderly [10,13] and inclusion of laboratory data is essential in modelling exercises which examine the relative impact of influenza and RSV. Both influenza A and B reports were selected into the modelling (P < 0 001) in addition to RCGP diagnostic indices, indicating that they are of value in estimating mortality.…”

“…Nicholson and colleagues [13] identified 9 RSV infections among 179 respiratory infections in residential homes in Leicester, U.K. Three of the 9 infections were associated with lower respiratory tract complications and 2 other patients died on days 5 and 8 of illness coinciding with RSV in the home. RSV infections occurred at the same time as influenza, rhinovirus, coronavirus and adenovirus infections, and the episodes caused by these viruses were clinically indistinguishable.…”

“…In Rochester, New York, nursing homes, 13 of 126 people (c. 10%) had serological evidence of RSV infection [14]. In four studies involving the elderly in homes or hospitals to which RSV and influenza serology were undertaken the ratio of influenza to RSV infection was 3:1 [10,11,13,14].…”

Influenza deaths in Leicestershire during the 1989–90 epidemic: implications for prevention

“…one, two, or three or more chronic medical conditions were estimated from the medical records of 162 elderly residents of 11 homes for the elderly in Leicestershire [15]. To [10,15].…”