In a prospective observational study, influenza vaccination prevented hospitalization among older home care patients

Influenza and pneumococcal vaccination in older adults living in nursing home: a survival analysis on the shelter study

Background

Influenza and pneumococcal vaccines have been proved to be effective and safe in preventing and controlling infection among elderly, reducing morbidity and mortality. However, some evidences raised health concerns related to these vaccinations. This study aims to identify prevalence and outcomes related to influenza and pneumococcal vaccinations in a large European population of frail old people living in nursing homes (NHs).

Methods

We conducted a survival analysis of NH residents participating to the Services and Health for Elderly in Long-TERm project, a prospective cohort study collecting information on residents admitted to 57 NH in eight countries (Czech Republic, England, Finland, France, Germany, Italy, The Netherlands and Israel). Clinical and demographical data were collected using the international resident assessement instrument for long-term care facilities. Incident mortality was recorded during 1-year follow-up. A shared-frailty Cox regression model was used to assess the impact of vaccination status on mortality.

Results

Mean age of 3510 participants was 84.6 years (SD = 7.7). In total, 81.7 and 27.0% received influenza and pneumococcal vaccination, respectively. Overall, 727 (20.7%) residents died during the follow-up period. After adjusting for potential confounders, which included age, sex, number of diseases, depression, cognitive and functional status, influenza (HR = 0.80; 95% CI 0.66-0.97) and the combination of influenza and pneumococcal vaccination (HR = 0.72; 95% CI 0.57-0.91), but not pneumococcal vaccination alone (HR = 0.52; 95% CI 0.25-1.06), were associated with a statistically significant reduction in mortality in respect of no vaccinations.

Conclusion

In a population of older adult living in NH influenza and the combination of influenza and pneumococcal vaccination were associated with a reduction in all-cause mortality respect to no vaccination.

Vaccines for preventing influenza in the elderly

BACKGROUND

The consequences of influenza in the elderly (those age 65 years or older) are complications, hospitalisations, and death. The primary goal of influenza vaccination in the elderly is to reduce the risk of death among people who are most vulnerable. This is an update of a review published in 2010. Future updates of this review will be made only when new trials or vaccines become available. Observational data included in previous versions of the review have been retained for historical reasons but have not been updated because of their lack of influence on the review conclusions.

OBJECTIVES

To assess the effects (efficacy, effectiveness, and harm) of vaccines against influenza in the elderly.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2016, Issue 11), which includes the Cochrane Acute Respiratory Infections Group's Specialised Register; MEDLINE (1966 to 31 December 2016); Embase (1974 to 31 December 2016); Web of Science (1974 to 31 December 2016); CINAHL (1981 to 31 December 2016); LILACS (1982 to 31 December 2016); WHO International Clinical Trials Registry Platform (ICTRP; 1 July 2017); and ClinicalTrials.gov (1 July 2017).

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs assessing efficacy against influenza (laboratory-confirmed cases) or effectiveness against influenza-like illness (ILI) or safety. We considered any influenza vaccine given independently, in any dose, preparation, or time schedule, compared with placebo or with no intervention. Previous versions of this review included 67 cohort and case-control studies. The searches for these trial designs are no longer updated.

DATA COLLECTION AND ANALYSIS

Review authors independently assessed risk of bias and extracted data. We rated the certainty of evidence with GRADE for the key outcomes of influenza, ILI, complications (hospitalisation, pneumonia), and adverse events. We have presented aggregate control group risks to illustrate the effect in absolute terms. We used them as the basis for calculating the number needed to vaccinate to prevent one case of each event for influenza and ILI outcomes.

MAIN RESULTS

We identified eight RCTs (over 5000 participants), of which four assessed harms. The studies were conducted in community and residential care settings in Europe and the USA between 1965 and 2000. Risk of bias reduced our certainty in the findings for influenza and ILI, but not for other outcomes.Older adults receiving the influenza vaccine may experience less influenza over a single season compared with placebo, from 6% to 2.4% (risk ratio (RR) 0.42, 95% confidence interval (CI) 0.27 to 0.66; low-certainty evidence). We rated the evidence as low certainty due to uncertainty over how influenza was diagnosed. Older adults probably experience less ILI compared with those who do not receive a vaccination over the course of a single influenza season (3.5% versus 6%; RR 0.59, 95% CI 0.47 to 0.73; moderate-certainty evidence). These results indicate that 30 people would need to be vaccinated to prevent one person experiencing influenza, and 42 would need to be vaccinated to prevent one person having an ILI.The study providing data for mortality and pneumonia was underpowered to detect differences in these outcomes. There were 3 deaths from 522 participants in the vaccination arm and 1 death from 177 participants in the placebo arm, providing very low-certainty evidence for the effect on mortality (RR 1.02, 95% CI 0.11 to 9.72). No cases of pneumonia occurred in one study that reported this outcome (very low-certainty evidence). No data on hospitalisations were reported. Confidence intervaIs around the effect of vaccines on fever and nausea were wide, and we do not have enough information about these harms in older people (fever: 1.6% with placebo compared with 2.5% after vaccination (RR 1.57, 0.92 to 2.71; moderate-certainty evidence)); nausea (2.4% with placebo compared with 4.2% after vaccination (RR 1.75, 95% CI 0.74 to 4.12; low-certainty evidence)).

AUTHORS' CONCLUSIONS

Older adults receiving the influenza vaccine may have a lower risk of influenza (from 6% to 2.4%), and probably have a lower risk of ILI compared with those who do not receive a vaccination over the course of a single influenza season (from 6% to 3.5%). We are uncertain how big a difference these vaccines will make across different seasons. Very few deaths occurred, and no data on hospitalisation were reported. No cases of pneumonia occurred in one study that reported this outcome. We do not have enough information to assess harms relating to fever and nausea in this population.The evidence for a lower risk of influenza and ILI with vaccination is limited by biases in the design or conduct of the studies. Lack of detail regarding the methods used to confirm the diagnosis of influenza limits the applicability of this result. The available evidence relating to complications is of poor quality, insufficient, or old and provides no clear guidance for public health regarding the safety, efficacy, or effectiveness of influenza vaccines for people aged 65 years or older. Society should invest in research on a new generation of influenza vaccines for the elderly.

Influenza vaccination for healthcare workers who care for people aged 60 or older living in long-term care institutions

BACKGROUND

A systematic review found that 3% of working adults who had received influenza vaccine and 5% of those who were unvaccinated had laboratory-proven influenza per season; in healthcare workers (HCWs) these percentages were 5% and 8% respectively. Healthcare workers may transmit influenza to patients.

OBJECTIVES

To identify all randomised controlled trials (RCTs) and non-RCTs assessing the effects of vaccinating healthcare workers on the incidence of laboratory-proven influenza, pneumonia, death from pneumonia and admission to hospital for respiratory illness in those aged 60 years or older resident in long-term care institutions (LTCIs).

SEARCH METHODS

We searched CENTRAL (2015, Issue 9), MEDLINE (1966 to October week 3, 2015), EMBASE (1974 to October 2015) and Web of Science (2006 to October 2015), but Biological Abstracts only from 1969 to March 2013 and Science Citation Index-Expanded from 1974 to March 2013 due to lack of institutional access in 2015.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and non-RCTs of influenza vaccination of healthcare workers caring for individuals aged 60 years or older in LTCIs and the incidence of laboratory-proven influenza and its complications (lower respiratory tract infection, or hospitalisation or death due to lower respiratory tract infection) in individuals aged 60 years or older in LTCIs.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed risk of bias. Effects on dichotomous outcomes were measured as risk differences (RDs) with 95% confidence intervals (CIs). We assessed the quality of evidence with GRADE.

MAIN RESULTS

We identified four cluster-RCTs and one cohort study (n = 12,742) of influenza vaccination for HCWs caring for individuals ≥ 60 years in LTCIs. Four cluster RCTs (5896 residents) provided outcome data that addressed the objectives of our review. The studies were comparable in their study populations, intervention and outcome measures. The studies did not report adverse events. The principal sources of bias in the studies related to attrition, lack of blinding, contamination in the control groups and low rates of vaccination coverage in the intervention arms, leading us to downgrade the quality of evidence for all outcomes due to serious risk of bias.Offering influenza vaccination to HCWs based in long term care homes may have little or no effect on the number of residents who develop laboratory-proven influenza compared with those living in care homes where no vaccination is offered (RD 0 (95% CI -0.03 to 0.03), two studies with samples taken from 752 participants; low quality evidence). HCW vaccination probably leads to a reduction in lower respiratory tract infection in residents from 6% to 4% (RD -0.02 (95% CI -0.04 to 0.01), one study of 3400 people; moderate quality evidence). HCW vaccination programmes may have little or no effect on the number of residents admitted to hospital for respiratory illness (RD 0 (95% CI -0.02 to 0.02, one study of 1059 people; low quality evidence). We decided not to combine data on deaths from lower respiratory tract infection (two studies of 4459 people) or all cause deaths (four studies of 8468 people). The direction and size of difference in risk varied between the studies. We are uncertain as to the effect of vaccination on these outcomes due to the very low quality of evidence. Adjusted analyses, which took into account the cluster design, did not differ substantively from the pooled analysis with unadjusted data.

AUTHORS' CONCLUSIONS

Our review findings have not identified conclusive evidence of benefit of HCW vaccination programmes on specific outcomes of laboratory-proven influenza, its complications (lower respiratory tract infection, hospitalisation or death due to lower respiratory tract illness), or all cause mortality in people over the age of 60 who live in care institutions. This review did not find information on co-interventions with healthcare worker vaccination: hand-washing, face masks, early detection of laboratory-proven influenza, quarantine, avoiding admissions, antivirals and asking healthcare workers with influenza or influenza-like illness (ILI) not to work. This review does not provide reasonable evidence to support the vaccination of healthcare workers to prevent influenza in those aged 60 years or older resident in LTCIs. High quality RCTs are required to avoid the risks of bias in methodology and conduct identified by this review and to test further these interventions in combination.

Are influenza-associated morbidity and mortality estimates for those ≥ 65 in statistical databases accurate, and an appropriate test of influenza vaccine effectiveness?

PURPOSES

To assess the accuracy of estimates using statistical databases of influenza-associated morbidity and mortality, and precisely measure influenza vaccine effectiveness.

PRINCIPAL RESULTS

Laboratory testing of influenza is incomplete. Death certificates under-report influenza. Statistical database models are used as an alternative to randomised controlled trials (RCTs) to assess influenza vaccine effectiveness. Evidence of the accuracy of influenza morbidity and mortality estimates was sought from: (1) Studies comparing statistical models. For four studies Poisson and ARIMA models produced higher estimates than Serfling, and Serfling higher than GLM. Which model is more accurate is unknown. (2) Studies controlling confounders. Fourteen studies mostly controlled one confounder (one controlled comorbidities), and limited control of confounders limits accuracy.

EVIDENCE FOR VACCINE EFFECTIVENESS WAS SOUGHT FROM

(1) Studies of regions with increasing vaccination rates. Of five studies two controlled for confounders and one found a positive vaccination effect. Three studies did not control confounders and two found no effect of vaccination. (2) Studies controlling multiple confounders. Of thirteen studies only two found a positive vaccine effect and no mortality differences between vaccinees and non-vaccinees in non-influenza seasons, showing confounders were controlled. Key problems are insufficient testing for influenza, using influenza-like illness, heterogeneity of seasonal and pandemic influenza, population aging, and incomplete confounder control (co-morbidities, frailty, vaccination history) and failure to demonstrate control of confounders by proving no mortality differences between vaccinees and non-vaccinees in non-influenza seasons.

MAJOR CONCLUSIONS

Improving model accuracy requires proof of no mortality differences in pre-influenza periods between the vaccinated and non-vaccinated groups, and reduction in influenza morbidity and mortality in seasons with a good vaccine match, more virulent strains, in the younger elderly with less immune senescence, and specific outcomes (laboratory-confirmed outcomes, pneumonia deaths). Proving influenza vaccine effectiveness requires appropriately powered RCTs, testing participants with RT-PCR tests, and comprehensively monitoring morbidity and mortality.

Influenza vaccination for healthcare workers who care for people aged 60 or older living in long-term care institutions

BACKGROUND

Healthcare workers' influenza rates are unknown but may be similar to those of the general public. Healthcare workers may transmit influenza to patients.

OBJECTIVES

To identify all randomised controlled trials (RCTs) and non-RCTs assessing the effects of vaccinating healthcare workers on the incidence of laboratory-proven influenza, pneumonia, death from pneumonia and admission to hospital for respiratory illness in those aged 60 years or older resident in long-term care institutions (LTCIs).

SEARCH METHODS

We searched CENTRAL 2013, Issue 2, MEDLINE (1966 to March week 3, 2013), EMBASE (1974 to March 2013), Biological Abstracts (1969 to March 2013), Science Citation Index-Expanded (1974 to March 2013) and Web of Science (2006 to March 2013).

SELECTION CRITERIA

Randomised controlled trials (RCTs) and non-RCTs of influenza vaccination of healthcare workers caring for individuals aged 60 years or older in LTCIs and the incidence of laboratory-proven influenza and its complications (lower respiratory tract infection, or hospitalisation or death due to lower respiratory tract infection) in individuals aged 60 years or older in LTCIs.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed risk of bias.

MAIN RESULTS

We identified four cluster-RCTs (C-RCTs) (n = 7558) and one cohort study (n = 12,742) of influenza vaccination for HCWs caring for individuals ≥ 60 years in LTCFs. Three RCTs (5896 participants) provided outcome data that met our criteria. These three studies were comparable in study populations, intervention and outcome measures. The studies did not report adverse events. The principal sources of bias in the studies related to attrition and blinding. The pooled risk difference (RD) from the three cluster-RCTs for laboratory-proven influenza was 0 (95% confidence interval (CI) -0.03 to 0.03) and for hospitalisation was RD 0 (95% CI -0.02 to 0.02). The estimated risk of death due to lower respiratory tract infection was also imprecise (RD -0.02, 95% CI -0.06 to 0.02) in individuals aged 60 years or older in LTCIs. Adjusted analyses which took into account the cluster design did not differ substantively from the pooled analysis with unadjusted data.

AUTHORS' CONCLUSIONS

The results for specific outcomes: laboratory-proven influenza or its complications (lower respiratory tract infection, or hospitalisation or death due to lower respiratory tract illness) did not identify a benefit of healthcare worker vaccination on these key outcomes. This review did not find information on co-interventions with healthcare worker vaccination: hand-washing, face masks, early detection of laboratory-proven influenza, quarantine, avoiding admissions, antivirals and asking healthcare workers with influenza or influenza-like-illness (ILI) not to work. This review does not provide reasonable evidence to support the vaccination of healthcare workers to prevent influenza in those aged 60 years or older resident in LTCIs. High-quality RCTs are required to avoid the risks of bias in methodology and conduct identified by this review and to test further these interventions in combination.

Influenza vaccination for healthcare workers who work with the elderly

BACKGROUND

Healthcare workers' (HCWs) influenza rates are unknown, but may be similar to the general public and they may transmit influenza to patients.

OBJECTIVES

To identify studies of vaccinating HCWs and the incidence of influenza, its complications and influenza-like illness (ILI) in individuals >/= 60 in long-term care facilities (LTCFs).

SEARCH STRATEGY

We searched CENTRAL (The Cochrane Library 2009, issue 3), which contains the Cochrane Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to 2009), EMBASE (1974 to 2009) and Biological Abstracts and Science Citation Index-Expanded.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and non-RCTs of influenza vaccination of HCWs caring for individuals >/= 60 in LTCFs and the incidence of laboratory-proven influenza, its complications or ILI.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed risk of bias.

MAIN RESULTS

We identified four cluster-RCTs (C-RCTs) (n = 7558) and one cohort (n = 12742) of influenza vaccination for HCWs caring for individuals >/= 60 in LTCFs. Pooled data from three C-RCTs showed no effect on specific outcomes: laboratory-proven influenza, pneumonia or deaths from pneumonia. For non-specific outcomes pooled data from three C-RCTs showed HCW vaccination reduced ILI; data from one C-RCT that HCW vaccination reduced GP consultations for ILI; and pooled data from three C-RCTs showed reduced all-cause mortality in individuals >/= 60.

AUTHORS' CONCLUSIONS

No effect was shown for specific outcomes: laboratory-proven influenza, pneumonia and death from pneumonia. An effect was shown for the non-specific outcomes of ILI, GP consultations for ILI and all-cause mortality in individuals >/= 60. These non-specific outcomes are difficult to interpret because ILI includes many pathogens, and winter influenza contributes < 10% to all-cause mortality in individuals >/= 60. The key interest is preventing laboratory-proven influenza in individuals >/= 60, pneumonia and deaths from pneumonia, and we cannot draw such conclusions.The identified studies are at high risk of bias.Some HCWs remain unvaccinated because they do not perceive risk, doubt vaccine efficacy and are concerned about side effects. This review did not find information on co-interventions with HCW vaccination: hand washing, face masks, early detection of laboratory-proven influenza, quarantine, avoiding admissions, anti-virals, and asking HCWs with ILI not to work. We conclude there is no evidence that vaccinating HCWs prevents influenza in elderly residents in LTCFs. High quality RCTs are required to avoid risks of bias in methodology and conduct, and to test these interventions in combination.

Vaccines for preventing influenza in the elderly

BACKGROUND

Vaccines have been the main global weapon to minimise the impact of influenza in the elderly for the last four decades and are recommended worldwide for individuals aged 65 years or older. The primary goal of influenza vaccination in the elderly is to reduce the risk of complications among persons who are most vulnerable.

OBJECTIVES

To assess the effectiveness of vaccines in preventing influenza, influenza-like illness (ILI), hospital admissions, complications and mortality in the elderly. To identify and appraise comparative studies evaluating the effects of influenza vaccines in the elderly. To document types and frequency of adverse effects associated with influenza vaccines in the elderly.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), which contains the Cochrane Acute Respiratory Infections (ARI) Group's Specialised Register (The Cochrane Library 2009, issue 4); MEDLINE (January 1966 to October Week 1 2009); EMBASE (1974 to October 2009) and Web of Science (1974 to October 2009).

SELECTION CRITERIA

Randomised controlled trials (RCTs), quasi-RCTs, cohort and case-control studies assessing efficacy against influenza (laboratory-confirmed cases) or effectiveness against influenza-like illness (ILI) or safety. Any influenza vaccine given independently, in any dose, preparation or time schedule, compared with placebo or with no intervention was considered.

DATA COLLECTION AND ANALYSIS

We grouped reports first according to the setting of the study (community or long-term care facilities) and then by level of viral circulation and vaccine matching. We further stratified by co-administration of pneumococcal polysaccharide vaccine (PPV) and by different types of influenza vaccines. We analysed the following outcomes: influenza, influenza-like illness, hospital admissions, complications and deaths.

MAIN RESULTS

We included 75 studies. Overall we identified 100 data sets. We identified one RCT assessing efficacy and effectiveness. Although this seemed to show an effect against influenza symptoms it was underpowered to detect any effect on complications (1348 participants). The remainder of our evidence base included non-RCTs. Due to the general low quality of non-RCTs and the likely presence of biases, which make interpretation of these data difficult and any firm conclusions potentially misleading, we were unable to reach clear conclusions about the effects of the vaccines in the elderly.

AUTHORS' CONCLUSIONS

The available evidence is of poor quality and provides no guidance regarding the safety, efficacy or effectiveness of influenza vaccines for people aged 65 years or older. To resolve the uncertainty, an adequately powered publicly-funded randomised, placebo-controlled trial run over several seasons should be undertaken.

Case management, preventive strategies, and caregiver attitudes among older adults in home care: results of the ADHOC study

BACKGROUND

Among older adults, integration of health services in a continuum of care with case management programs was shown to reduce progression of functional decline, hospitalization, and institutionalization. We hypothesized that such an approach may also result in a higher rate of use of preventive strategies and lower caregiver distress.

METHODS

Data were from the baseline assessment of the AgeD in HOme Care project, a study enrolling subjects aged 65 years or older receiving home care in Europe. Preventive strategies considered were: (1) blood pressure measured in the last 2 years; (2) influenza vaccination in the last 2 years; (3) medication reviewed in the last 180 days.

RESULTS

Mean age of participants was 82.3 years and 2971 (74%) were women; 1539 (38%) received home care program based on case management. Overall, 1350 (88%) of 1539 participants in the case manager group and 2046 (83%) of 2468 of those in the no case manager group had blood pressure measured in the last 2 years (P < .001). After adjusting for potential confounders, this result was still statistically significant (OR 1.31, 95% CI: 1.08-1.59). Similarly, more participants in the case manager groups received influenza vaccination (1083/1539 [70%] versus 1293/2468 [52%], P < .001) and had medication reviewed (312/1539 [20%] versus 356/2468 [15%], P < .001) compared with those in the no case manager group and these associations were confirmed after adjusting for confounders (OR: vaccination 2.08, 95% CI: 1.81-2.39; medication review 1.69, 95% CI 1.42-2.01). Furthermore, the caregivers of subjects in case manager group were less likely to be unable to continue in caring activities (49/1320 [4%] versus 134/2129 [6%], P = .01) and less dissatisfied (28/1320 [2%] versus 83/1129 [4%], P < .001) compared with those in the no case manager group.

CONCLUSIONS

Home care services based on case management approach result in a higher rate of use of preventive strategies and lower burden for caregivers.