The terminology of infection in care homes is different

Pneumonia refers to infections of the lung parenchyma that produce visible infiltrates on chest radiography, often associated with cough, fever, breathlessness and malaise. If there are no visible changes on the chest radiograph then the illness is called a lower respiratory tract infection (LRTI). It has been proposed that nursing home-acquired pneumonia (NHAP) be considered separately from community-acquired pneumonia (CAP) due to the likelihood that the causative organisms, and therefore the choice of antibiotic, will differ.Reference El-Solh, Sikka, Ramadan and Davies¹⁰

Most of the evidence surrounding NHAP comes from US studies and it is difficult to compare the prevalence of NHAP in US and non-US populations because of international variation in care homes and the medical therapies to which residents are exposed. For example, in the US, nursing home residents with severe pneumonia may be intubated and ventilatedReference El Solh and Saliba^11, Reference El Solh, Pietrantoni and Bhat¹² – which may both facilitate and cause higher diagnosis of drug-resistant pathogens. Such practice would be rare in the UK.

Healthcare-associated pneumonia (HCAP) is a relatively new term that includes patients in nursing homes as being at higher risk of having pneumonia caused by multi-resistant organisms.Reference Kollef, Shorr and Tabak¹³ Taking the UK as an example, a study conducted in 2001 compared the organisms causing community-acquired pneumonia in nursing home residents with age- and dependency-matched controls living in their own home, demonstrating little difference between the two.Reference Lim and Macfarlane¹⁴ It is therefore unclear whether NHAP or HCAP are useful classifications in the UK.

The terminology surrounding influenza in care homes is the same as in the general population, but is described here to clarify discussion about influenza subtypes later in the article. Influenza refers to the infections caused by the influenza virus, of which there are three types, A, B and C, classified according to viral matrix- and nucleo-proteins. Of these, only A and B cause significant infection in humans. Influenza viruses are described according to their surface antigens, haemaglutinin and neuraminidase, which are glycoproteins known to play key roles in the replication cycle of the virus. Influenza A expresses 16 subtypes of haemaglutinin (H1–H16) and 9 subtypes of neuraminidase (N1–N9), whilst influenza B expresses only one type of each antigen.

The epidemiology of pneumonia and influenza in care homes is different from in the general population

Care homes are unique ecological niches for infection because their residents have reduced function, have numerous co-morbidities, and have higher rates of dementia. They live in communities in which they are grouped with other patients of similar age and vulnerability. A consequence of this is that the epidemiology of pneumonia and influenza in care homes, particularly in terms of outbreak management and infection control, is different from that in both the acute hospital and community sectors.

In general, mortality from pneumonia in care home residents is high (12–21%),Reference Degelau, Guay and Straub^15–Reference Quagliarello, Ginter and Han¹⁸ and residents are more likely to die of pneumonia than other healthcare-associated infections.Reference Engelhart, Hanses-Derendorf, Exner and Kramer¹⁹ The higher mortality in residents is explained to a large extent by their pre-morbid status, with mortality rates attenuated compared with community controls when weight loss, dementia, aspiration risk and functional status are considered.Reference Lim and Macfarlane^14, Reference van Der Steen, Mehr and Kruse²⁰

Bacterial pneumonia is not generally regarded as contagious and isolation measures are therefore not routinely recommended. However, occasional outbreaks have been reported in care homes,Reference Nuorti, Butler and Crutcher^21, Reference Quick, Hoge and Hamilton²² presumably because of the close proximity in which residents live. Where reported, outbreaks have been associated with low pneumococcal vaccination rates, making a compelling case for vaccination in this cohort, despite concerns about vaccine efficacy (see below).

By contrast, influenza is characterized by epidemics. Influenza surface antigens frequently undergo structural modification, leading to a period when populations become vulnerable to infection whilst population immunity catches up. Subtle modification from season to season, usually caused by point mutation in the genetic code for the surface glycoproteins, is known as antigenic drift and is the driving factor behind seasonal influenza outbreaks. Rarely, entirely novel H or N antigens emerge, often as a consequence of genetic reassortment with swine or avian influenza viruses. This is known as antigenic shift and results in a strain to which there is limited or no population immunity, which often results in pandemic influenza.

The concept of an ‘influenza season’ comes from temperate latitudes in the northern and southern hemispheres, where characteristic peaks of influenza are recorded in the autumn and winter months. Care home outbreaks mirror the prevalence in the wider population and therefore tend also to be seasonal at these latitudes. In tropical climates, influenza is more common during the wet season but seasonal differences are less pronounced.Reference Nicholson, Wood and Zambon²³

Once introduced into a care home, influenza can spread rapidly because of close contact among residents, their poor overall health status and the challenges of infection control in care homes. Rates of pneumonic conversion from influenza can be as high as 42% during outbreaks.Reference Loeb, McGeer and McArthur²⁴ During the influenza season, case-fatality rates for care home residents regularly exceed 5% and have been reported to exceed 70% during outbreaks.Reference Hayward, Harling and Wetten^25–Reference Saah, Neufeld and Rodstein²⁸ As with pneumonia, the risk of mortality or significant morbidity from influenza increases with age and co-morbidities.Reference Thompson, Shay and Weintraub²⁹

Spread of influenza is likely to occur via close personal contact, and in particular through contact with oral secretions.Reference Brankston, Gitterman, Hirji, Lemieux and Gardam³⁰ Staff represent a potential vector for spread through their role in mouth care and feeding. Recommended measures to minimize spread during an outbreak include regular handwashing for staff, ready availability of portable alcohol gel for hand cleansing and, where staff have prolonged close contact with residents, the use of face-masks, gloves and aprons.Reference Jefferson, Foxlee and Mar^31–33 However, the evidence for effectiveness of infection control in the care home setting is limited.Reference Nicolle³⁴ This is possibly due to the fact that hospital-style measures are made difficult by the need to provide a homely setting and allow freedom of movement. Lack of dedicated infection control staff and low staff-to-resident ratios also contribute.

Oropharyngeal commensals are different in the care home population

Lower respiratory tract infections result from the combination of a potential pathogen adhering to the oro- or nasopharynx, the provision of an easy path to the lower respiratory tract (e.g. tendency to aspirate), and an immune system unable to eradicate the pathogen either at the oro- or nasopharynx or in the lungs. Age, number of co-morbidities,Reference Harkness, Bentley and Roghmann^35–Reference Fine, Auble and Yealy³⁷ malnutritionReference Morley and Silver³⁸ and frailty influence the latter.

Micro-aspiration, where small amounts of oral-pharyngeal secretions are aspirated into the lungs, is likely to be an aetiological factor in most pneumonias and explains how differences in oral-pharyngeal colonization lead to differences in the spectrum of organisms causing pneumonia in different populations.Reference Nicolle, McLeod, McIntyre and MacDonell^7, Reference Preston, Gosney, Noon and Martin^39, Reference Russell, Boylan, Kaslick, Scannapieco and Katz⁴⁰

Oral colonization with pathogens known to cause pneumonia (e.g. P. aeruginosa, S. aureus) occurs more commonly in hospitalized and institutionalized people.Reference Nicolle, McLeod, McIntyre and MacDonell^7, Reference Preston, Gosney, Noon and Martin^39, Reference Russell, Boylan, Kaslick, Scannapieco and Katz⁴⁰ These bacteria are also encountered very commonly in those with nasogastric tubes in situ.Reference Leibovitz, Plotnikov, Habot, Rosenberg and Segal^41, Reference Leibovitz, Plotnikov and Habot⁴² In addition, both community- and hospital-acquired pneumonias have been associated with proton pump inhibitor prescription,Reference Herzig, Howell and Ngo^43, Reference Laheij, Sturkenboom and Hassing⁴⁴ suggesting possible gastric bacterial overgrowth as an explanation for the presence of these bacteria.

In addition to guiding antibiotic prescribing for pneumonia in care home residents, these data suggest a possible role for manipulating the organisms that colonize the oropharyngeal tract as a way of modifying pneumonia risk in care home residents.

Diagnosing pneumonia or influenza in care home residents is more difficult than in the general population

Typical symptoms of LRTI include cough, fever, breathlessness, malaise, myalgia and pleuritic pain. Viral infections may also cause upper respiratory tract symptoms such as sore throat and sneezing. As with many older patients, the clinical presentation of pneumonia in care home residents is often non-specific because of general frailty, symptoms of co-morbid illness, impaired communication and/or cognition, and altered response to sepsis.Reference Nicolle³⁴ Fever, productive cough and pleuritic chest pain are less common in older people, whilst non-specific presentations such as falls, delirium, anorexia or generalized weakness are common.Reference Lim and Macfarlane^14, Reference Gavazzi and Krause⁴⁵

The only English-language guideline for diagnosing pneumonia in care home residents comes from the US and is based upon consensus by a multi-speciality consensus panel.Reference Hutt, Kramer, Hutt and Kramer⁴⁶ It suggests that a diagnosis of probable pneumonia can be made based on two of the following factors being present: new or worsening cough, new purulent sputum, fever >100°F, or over 2°F above normal, or <96°F, dyspnoea, respiratory rate >25, tachycardia, new or worsening hypoxia, pleuritic chest pain, decline in cognition or functional status, or new crepitations or wheezes heard on auscultation. Unlike other pneumonia guidelines, a chest radiograph is not required for diagnosis. The rationale for this is not made clear but, possibly, is a pragmatic decision based on the limited access to radiography in the care home setting and the possible deleterious effects of moving to an acute care setting to obtain an X-ray.

The presence of such symptoms is not, however, a reliable indicator of pneumonia, as opposed to other lower respiratory tract infections, nor does it give any indication as to the causative organism.Reference Loeb, McGeer and McArthur²⁴ Hui et al.Reference Hui, Woo and Hui⁴⁷ found the aetiological agent in such presentations amongst care home residents to be bacterial in 53.3% of the cases where a pathogen was identified. Influenza virus type A or B caused 7.4% of cases. Respiratory syncytial virus (RSV), metapneumovirus and parainfluenza were all more prevalent than influenza.

It is difficult to grade severity of pneumonia in older patients, including care home residents. The CURB-65 criteria (widely used in community-acquired pneumonia) have a high negative predictive value (95.9%) and sensitivity (85.2%), but a low specificity (57%) and positive predictive value (24.5%) in community-dwelling older patients.Reference Myint, Kamath, Vowler, Maisey and Harrison⁴⁸ This makes it easy to decide who has non-severe pneumonia but much more difficult to establish with certainty who has severe pneumonia and therefore requires hospitalization – strict adherence to the CURB criteria will result in a significant number of unnecessary hospitalizations, particularly as high-quality care can often be provided within the care home setting.

Given the low sensitivity and specificity of clinical diagnosis (i.e. those with pneumonia at autopsy not displaying clinical symptoms or signs, and other respiratory illnesses being classified as pneumonia), a gold-standard investigation for pneumonia would be useful. Unfortunately, no such test is available. Inter-rater agreement between radiologists interpreting chest radiographs of nursing home residents is described as ‘fair’Reference Loeb, Carusone and Marrie⁴⁹ and computed tomography does not reliably establish the diagnosis.Reference Masterton, Galloway and French⁵⁰

Influenza is diagnosed by clinical symptoms during epidemic or pandemic situations and by laboratory testing during outbreaks. Real-time polymerase chain reaction (PCR) analysis of nose and throat swabs in viral transport media allows same-day diagnosis to aid in infection control during outbreaks, although this is dependent on primary care physicians both making the provisional diagnosis and requesting the investigation.

Mouth care may play a specific role in prophylaxis of LRTIs in care homes

Given that the pathogenesis of NHAP appears to be microaspiration of infected oral secretions, it is possible that improving oral hygiene may reduce rates of pneumonia. Two systematic reviews have been undertaken considering oral hygiene and pneumonia. Scannapieco et al. reviewed 21 studies and concluded that further research was needed but that evidence pointed to a link between the two.Reference Scannapieco, Bush and Paju⁵¹ Azparnooh et al. suggested a significant effect from oral hygiene, but included papers from a wider group of patients (e.g. intensive care and nursing home) and considered a wider range of diseases.Reference Azarpazhooh, Leake, Azarpazhooh and Leake⁵² Randomized controlled trials in this area are necessary.

One study considered in the reviews above is worth highlighting. Yoneyama et al.Reference Yoneyama, Yoshida and Ohrui^17, Reference Yoneyama, Yoshida, Matsui and Sasaki⁵³ randomized 418 nursing home residents to receive oral hygiene (manual toothbrushing plus povidone iodine oral scrubs) or no intervention, with the outcome measure being radiologically confirmed pneumonia. Thirty-four of 182 participants developed pneumonia in the no-oral care group, compared with 21 of 184 in the oral care group (OR 1.67, CI: 1.01–2.75, P = 0.04). This study is the only intervention study in non-ventilated people that is adequately powered and has not yet been repeated.

Bassim et al. subsequently undertook an intervention trial where one ward of patients was assigned an oral care practitioner and another ward was not.Reference Bassim, Gibson and Ward⁵⁴ The intervention group had a similar rate of pneumonia at the end of the study, but it was noted that this group would have been expected to have a higher rate given their higher prevalence of co-morbidities. When adjusted for risk factors such as age, functional status, cognitive impairment and clinical suspicion of aspiration pneumonia, the odds ratio for death in the no oral care group was 3.57 (P = 0.3).

There is no evidence that feeding strategies modify pneumonia risk

Given that both aspiration and malnutrition represent risk factors for developing LRTIs and that both are common in the care home population, it seems logical to consider improving feeding strategies as a preventative intervention. Loeb et al. conducted a systematic review of feeding interventions to prevent aspiration pneumonia in 2003, and retrieved 8 randomized controlled trials evaluating positioning changes, dietary interventions, pharmacological therapies, oral hygiene and tube feeding.Reference Loeb, Becker, Eady and Walker-Dilks⁵⁵ None of the studies retrieved showed positive results; however, most were statistically underpowered. Further work in this area has been suggested.

Vaccination against pneumonia and influenza in care home residents is less effective than in the general population

Streptococcus pneumoniae remains an important cause of NHAP and is the only organism with an available vaccine for older people. The World Health Organisation recommends that all adults over the age of 65 be vaccinated with the 23-valent Pneumococcal vaccine (PPV23). While the body of evidence available suggests a protective effect from the vaccine against invasive pneumococcal diseaseReference Andrews, Counahan and Hogg⁵⁶ (that is pneumococci detected from any site), the vaccine is less effective in older than younger people,Reference Dominguez, Salleras and Fedson⁵⁷ and immunity wanes over time.Reference Konradsen and Konradsen⁵⁸

When end-points such as hospitalization for pneumonia are considered rather than invasive pneumococcal disease, the vaccine appears to be ineffective in older people.Reference Skull, Andrews and Byrnes⁵⁹ Huss et al. recently re-analysed vaccine trials, and found that the vaccine conferred little protection once trials with inadequate blinding were excluded.Reference Huss, Scott, Stuck, Trotter and Egger^60, Reference Jefferson⁶¹ As stated earlier, the PPV23 vaccination may confer some herd immunity, reducing the likelihood of pneumococcal outbreaks in care homes; however, the evidence for this is based around case reports. The risk–benefit ratio of pneumococcal vaccination in frail older people therefore remains uncertain and guidelines may be subject to revision in the future.

Similarly, most developed and many developing countries now recommend routine vaccination of older citizens against influenza.Reference van Essen, Palache, Forleo and Fedson⁶² Whilst such guidelines necessarily include the care home population, the World Health Organisation guideline identifies care home residents as being at particularly high risk, and therefore representing a priority for influenza vaccination.⁶³

Current recommendations are based on randomized controlled trials demonstrating efficacy of influenza vaccination that were conducted in young, healthy, ambulatory populations.Reference Demicheli, Di Pietrantonj, Jefferson, Rivetti and Rivetti⁶⁴ No such work has been undertaken in the care home population and would now be considered unethical in the face of overwhelming expert consensus that vaccination should take place. Observational cohort studies, however, suggest that influenza vaccination in this group is effective and reduces the incidence of respiratory infection by 33–42% and the risk of pneumonia by 43%.Reference Monto, Hornbuckle and Ohmit^65, Reference Ohmit, Arden and Monto⁶⁶ This is compared with a reduction in the incidence of influenza of 78% in young fit subjects. Older patients are less responsive to vaccination,Reference Foster, Talsma and Furumoto-Dawson⁶⁷ probably because of immunosenescence,Reference Monto, Ansaldi and Aspinall⁶⁸ and lower rates of seroconversion and seroprotection are seen following influenza vaccination in the elderly population compared with younger controls.Reference Goodwin, Viboud and Simonsen⁶⁹ However, despite its lower efficacy, observational studies suggest that homes with high uptake of influenza vaccination demonstrate a lower incidence of influenza-like illness,Reference Serie, Barme and Hannoun^26, Reference Monto, Hornbuckle and Ohmit⁶⁵ again suggesting a possible role for herd immunity.

Vaccination of staff against influenza is important in care homes

Two large cluster-randomized controlled trials, and a Cochrane review drawn from them, have demonstrated that immunization of staff has no effect upon incidence of influenza in care home residents but does reduce mortality, largely by reducing the incidence of complications.Reference Hayward, Harling and Wetten^25, Reference Carman, Elder and Wallace^70, Reference Thomas, Jefferson, Demicheli and Rivetti⁷¹ This effect is only seen when residents are also immunized. No such data exist for staff vaccination against pneumococcus.

Despite the demonstrated efficacy of staff vaccination, uptake rates for flu vaccines amongst health care workers are historically low. Only 16.5% of health care workers in England, for example, accepted vaccination in the 2008–2009 influenza season, despite the vaccine being freely available and uptake being encouraged by employers.Reference Begum and Pebody⁷² Immunization rates in Dutch care home workers have been reported at 11%, despite national guidelines recommending universal immunization for staff.Reference Looijmans-van den Akker, van Delden and Hak⁷³

Targeted interventions, including education programmes, financial incentives and reverse consent – where workers have to sign a consent form to demonstrate that they understand the risks taken by refusing vaccination – can improve vaccine uptake rates.Reference Sand, Lynn, Bardenheier, Seow and Nace^74, Reference Hofmann, Ferracin, Marsh and Dumas⁷⁵ However, such practices are not widespread. Mandatory vaccination of care home workers, where employment is conditional upon vaccination status, has been suggested as a possible solution.Reference Jordan and Hayward⁷⁶ The ethical challenges of such a policy are clear – balancing the need to protect patients from infection against the loss of autonomy for staff and the small possibility that they may suffer harmful side-effects as a consequence of vaccination – and thus it remains the subject of debate rather than policy.Reference Jordan and Hayward^76, Reference van Delden, Ashcroft and Dawson⁷⁷

The evidence-base and guidelines for chemoprophylaxis in care homes are different from the wider population

Given the above comments about oral hygiene and feeding interventions, it is useful to consider pharmacological interventions to prevent aspiration pneumonia. El Solh et al. conducted a systematic review of these in 2007, considering angiotensin converting enzyme inhibitors, capsaicin, amantadine, cabergoline, theophylline and cilostazol.Reference El Solh and Saliba¹¹ The latter four drugs could not be recommended due to adverse effects, and there was insufficient evidence to recommend the former two. The review concluded that further large scale randomized controlled trials were needed.

An earlier systematic review by Loeb et al.Reference Loeb, Becker, Eady and Walker-Dilks⁵⁵ considered use of the drugs cilostazol and amantadine, and found that both lowered pneumonia incidence at 3-year follow-up; stating, however, that both have a high incidence of undesirable side-effects that limit their widespread use.

Neuraminidase inhibitors may be used to prevent influenza infection in exposed people. Indeed, the evidence for chemoprophylaxis is more convincing than that for treatment in care home residents. A randomized placebo-controlled trial of oseltamivir in 548 nursing home residents whose co-residents had laboratory-confirmed influenza demonstrated reduced incidence of pneumonia, antibiotic prescribing and case mortality at 8-week follow-up.Reference Peters, Gravenstein and Norwood⁷⁸ A similar randomized placebo-controlled trial of zanamivir in 494 residents demonstrated no effect on the incidence of laboratory-confirmed influenza, but a statistically significant 70% reduction in the incidence of influenza associated with pyrexial symptoms – possibly a clinically significant finding.Reference Ambrozaitis, Gravenstein and Essen⁷⁹

The UK National Institute for Clinical Excellence (NICE) recommends use of oseltamivir and zanamivir for post-exposure prophylaxis in at-risk people living in long-term residential or nursing homes, whether or not they are vaccinated.⁸⁰ Similar guidance on prophylaxis has been issued by the US Centre for Disease Control and Prevention (CDC).⁸¹

Oseltamivir-resistant strains of influenza have recently been detected in both the US and Europe. Currently, this resistance is limited only to H1N1 strains.Reference Moscona⁸² No zanamivir-resistant strains have been identified and it is postulated that the molecular structure of zanamavir means that it is fundamentally less likely to engender resistance. Oseltamivir is taken orally, whilst zanamivir is administered by inhalation using a diskhaler device. The inhalation route means that zanamavir is not recommended for use in patients with underlying lung disease, and some older patients have been shown to find loading and priming the inhaler difficult.Reference Diggory, Fernandez, Humphrey, Jones and Murphy⁸³ Both of these factors limit its usefulness in the care home population.

The choice of antibiotic therapy for pneumonia is more complex in the care home population

Intravenous antibiotic therapy does not appear to confer a survival advantage in care home residents.Reference van Der Steen, Mehr and Kruse²⁰ Therefore residents can be treated in situ with oral antibiotic therapy and only require admission to hospital where they are unable to take oral medications, or require oxygen or intravenous fluids – which are not possible in the care home setting in many countries. The primary consideration in treating care home pneumonias is matching antibiotic therapy to the organisms prevalent in the care home population, as inadequate antibiotic therapy is associated with higher mortality.Reference El-Solh, Sikka, Ramadan and Davies¹⁰

The introduction of widespread antibiotic use has seen the emergence of less pathogenic bacteria causing respiratory infections in older people, including Staphylococcus aureus, coliform bacteria and Pseudomonas aeruginosa. Reference Garb, Brown and Garb^84–Reference Johanson and Dever⁸⁶ Residents seem to be at particular risk of drug-resistant pneumonia if they have poorer functional status, have received antibiotics within the past 90 days or have had a recent hospital stay.Reference El Solh, Pietrantoni and Bhat^12, Reference Brito and Niederman⁸⁷

This has led to revised antibiotic guidelines, in the US at least, for care home residents. New guidelines were issued by the American Thoracic Society in 2005⁸⁸ covering HCAP that have been applied to nursing home residents hospitalized with NHAP and have changed recommendations to include antibiotic cover for the more unusual pathogens seen in this group.

El Solh et al. compared outcomes of 334 nursing home residents hospitalized with NHAP/HCAP, of which 76 were treated using the new 2005 guideline and 258 were treated using the 2003 guideline, which did not include cover for MRSA or Pseudomonas aeruginosa.Reference El Solh, Akinnusi and Alfarah¹⁶ Despite the rationality of this approach, there was no difference in the time to clinical stability, in-hospital or 30-day mortality. This, combined with the uncertainty over whether pathogens in other countries mirror those seen in US nursing homes, means that standard CAP antibiotic protocols are used as first-line treatment for care home residents in many regions, with more broad-spectrum therapies used only if patients fail to respond to treatment.

The guidelines for treating influenza in the care home population are different – although the evidence-base for this is uncertain

In treating patients with proven influenza, neuraminidase inhibitors have been shown to reduce the number of days until alleviation of symptoms, return to normal activity or resolution of fever. However, no specific treatment trials have been undertaken in the care home population and, where high-risk and elderly populations have been studied, the treatment effect, although present, has failed to achieve statistical significance.Reference Burch, Corbett and Stock⁸⁹ The elderly cohorts in these studies were small and, as a consequence, they were inadequately powered to measure complications as an outcome.

Despite the uncertainty about treatment effect, NICE regards the care home population as high-risk with respect to influenza and suggests that, when the virus is known to be circulating, treatment with oseltamivir should be commenced for residents with flu-like illness. Treatment is also supported for influenza-like illness in care home residents outside of influenza season but only when virological confirmation that influenza is the aetiological agent has been made.⁹⁰

These guidelines are not replicated elsewhere in the world and recent concern has focused on possible inconsistencies in the pharmaceutical research undertaken to evaluate oseltamivir, upon which NICE have based their recommendations.Reference Cohen⁹¹ It is therefore possible, particularly given the paucity of care home specific data, that these guidelines will be subject to review in the future.

Oseltamivir has recently been the subject of much attention as a consequence of its heavy utilization for treatment of infected individuals in some regions during the current swine-origin influenza A virus (S-OIV) pandemic. The requirements for commencement in the context of a pandemic vary from country to country, as does the requirement for virological confirmation of infection by throat swab prior to commencement. In most cases, however, the elderly population, incorporating care home residents, are identified as a high-risk group, where treatment can be commenced even in the absence of a pyrexia.^{92, 93}

The threat posed by pandemic influenza is different in care homes than in the wider population

A novel H1N1 swine-origin influenza A virus (S-OIV) emerged in California and Mexico in April 2009⁹⁴ and has since spread around the world. The World Health Organisation (WHO) has defined this as a pandemic based upon its criterion of sustained human-to-human spread over multiple geographical regions.⁹⁵

At a population level, care home residents are potentially at lower risk from this virus than would conventionally be the case during a pandemic. Under-60s make up the majority of serologically confirmed cases of influenza, with evidence that up to 33% of over-60s carry antibodies that are protective against S-OIV.⁹⁶ This is likely to be a consequence of close similarities between the antigen profile of S-OIV and the strains of human H1N1 in prevalent circulation before the 1950s.Reference Peiris, Poon and Guan⁹⁷ At an individual level, however, care home residents remain at increased risk of secondary complications if they contract the virus because of their frailty and co-morbidities.

Pandemic influenza will challenge care homes both as care providers and as organizations. Contingencies will be required to deal with increased care requirements amongst residents, for isolation of infected residents and to cover periods of staff absence.Reference Fell⁹⁸ If homes are closed to new admissions during a pandemic, as is routine practice during normal influenza outbreaks, this will lead to loss of financial income, which will be compounded if the mortality rate is high. The importance of these issues varies from country to country, depending on the economic model underpinning the care home sector. In the UK, for example, care homes are predominantly run as small private companies that are particularly vulnerable to the economic pressures of a flu pandemic.Reference Fell⁹⁸ In the US, by contrast, nursing homes might be called on to deliver first-care if acute hospital facilities become overwhelmed, providing an additional stressor during a difficult time but also representing a possible revenue stream.Reference Mody and Cinti⁹⁹ There is evidence, however, that the care home sector in both countries has been engaged poorly in pandemic flu planning and, as a consequence, is potentially under-prepared.Reference Fell^98, Reference Mody and Cinti⁹⁹

Immunization practices for care home residents during a pandemic will vary depending upon national policies. In the UK, for example, over-65s in high-risk groups, including the care home population, will be vaccinated as part of the first wave of vaccination.³³ In the US, by contrast, this group are not listed as high priority – with attention focusing instead on younger patients with co-morbidities.¹⁰⁰

Conflicts of interest

The authors declared no conflicts of interest.