Influenza and pneumococcal vaccination of the elderly: newer vaccines and prospects for clinical benefits at the margin

Interventions to increase influenza vaccination rates of those 60 years and older in the community

BACKGROUND

The effectiveness of interventions to increase influenza vaccination uptake in people aged 60 years and older varies by country and participant characteristics. This review updates versions published in 2010 and 2014.

OBJECTIVES

To assess access, provider, system, and societal interventions to increase the uptake of influenza vaccination in people aged 60 years and older in the community.

SEARCH METHODS

We searched CENTRAL, which includes the Cochrane Acute Respiratory Infections Group's Specialised Register, MEDLINE, Embase, CINAHL, and ERIC for this update, as well as WHO ICTRP and ClinicalTrials.gov for ongoing studies to 7 December 2017. We also searched the reference lists of included studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and cluster-randomised trials of interventions to increase influenza vaccination in people aged 60 years or older in the community.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as specified by Cochrane.

MAIN RESULTS

We included three new RCTs for this update (total 61 RCTs; 1,055,337 participants). Trials involved people aged 60 years and older living in the community in high-income countries. Heterogeneity limited some meta-analyses. We assessed studies as at low risk of bias for randomisation (38%), allocation concealment (11%), blinding (44%), and selective reporting (100%). Half (51%) had missing data. We assessed the evidence as low-quality. We identified three levels of intervention intensity: low (e.g. postcards), medium (e.g. personalised phone calls), and high (e.g. home visits, facilitators).Increasing community demand (12 strategies, 41 trials, 53 study arms, 767,460 participants)One successful intervention that could be meta-analysed was client reminders or recalls by letter plus leaflet or postcard compared to reminder (odds ratio (OR) 1.11, 95% confidence interval (CI) 1.07 to 1.15; 3 studies; 64,200 participants). Successful interventions tested by single studies were patient outreach by retired teachers (OR 3.33, 95% CI 1.79 to 6.22); invitations by clinic receptionists (OR 2.72, 95% CI 1.55 to 4.76); nurses or pharmacists educating and nurses vaccinating patients (OR 152.95, 95% CI 9.39 to 2490.67); medical students counselling patients (OR 1.62, 95% CI 1.11 to 2.35); and multiple recall questionnaires (OR 1.13, 95% CI 1.03 to 1.24).Some interventions could not be meta-analysed due to significant heterogeneity: 17 studies tested simple reminders (11 with 95% CI entirely above unity); 16 tested personalised reminders (12 with 95% CI entirely above unity); two investigated customised compared to form letters (both 95% CI above unity); and four studies examined the impact of health risk appraisals (all had 95% CI above unity). One study of a lottery for free groceries was not effective.Enhancing vaccination access (6 strategies, 8 trials, 10 arms, 9353 participants)We meta-analysed results from two studies of home visits (OR 1.30, 95% CI 1.05 to 1.61) and two studies that tested free vaccine compared to patient payment for vaccine (OR 2.36, 95% CI 1.98 to 2.82). We were unable to conduct meta-analyses of two studies of home visits by nurses plus a physician care plan (both with 95% CI above unity) and two studies of free vaccine compared to no intervention (both with 95% CI above unity). One study of group visits (OR 27.2, 95% CI 1.60 to 463.3) was effective, and one study of home visits compared to safety interventions was not.Provider- or system-based interventions (11 strategies, 15 trials, 17 arms, 278,524 participants)One successful intervention that could be meta-analysed focused on payments to physicians (OR 2.22, 95% CI 1.77 to 2.77). Successful interventions tested by individual studies were: reminding physicians to vaccinate all patients (OR 2.47, 95% CI 1.53 to 3.99); posters in clinics presenting vaccination rates and encouraging competition between doctors (OR 2.03, 95% CI 1.86 to 2.22); and chart reviews and benchmarking to the rates achieved by the top 10% of physicians (OR 3.43, 95% CI 2.37 to 4.97).We were unable to meta-analyse four studies that looked at physician reminders (three studies with 95% CI above unity) and three studies of facilitator encouragement of vaccination (two studies with 95% CI above unity). Interventions that were not effective were: comparing letters on discharge from hospital to letters to general practitioners; posters plus postcards versus posters alone; educational reminders, academic detailing, and peer comparisons compared to mailed educational materials; educational outreach plus feedback to teams versus written feedback; and an intervention to increase staff vaccination rates.Interventions at the societal levelNo studies reported on societal-level interventions.Study funding sourcesStudies were funded by government health organisations (n = 33), foundations (n = 9), organisations that provided healthcare services in the studies (n = 3), and a pharmaceutical company offering free vaccines (n = 1). Fifteen studies did not report study funding sources.

AUTHORS' CONCLUSIONS

We identified interventions that demonstrated significant positive effects of low (postcards), medium (personalised phone calls), and high (home visits, facilitators) intensity that increase community demand for vaccination, enhance access, and improve provider/system response. The overall GRADE assessment of the evidence was moderate quality. Conclusions are unchanged from the 2014 review.

Interventions to increase influenza vaccination rates of those 60 years and older in the community

BACKGROUND

The effectiveness of interventions to increase the uptake of influenza vaccination in people aged 60 and older is uncertain.

OBJECTIVES

To assess access, provider, system and societal interventions to increase the uptake of influenza vaccination in people aged 60 years and older in the community.

SEARCH METHODS

We searched CENTRAL (2014, Issue 5), MEDLINE (January 1950 to May week 3 2014), EMBASE (1980 to June 2014), AgeLine (1978 to 4 June 2014), ERIC (1965 to June 2014) and CINAHL (1982 to June 2014).

SELECTION CRITERIA

Randomised controlled trials (RCTs) of interventions to increase influenza vaccination uptake in people aged 60 and older.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and extracted influenza vaccine uptake data.

MAIN RESULTS

This update identified 13 new RCTs; the review now includes a total of 57 RCTs with 896,531 participants. The trials included community-dwelling seniors in high-income countries. Heterogeneity limited meta-analysis. The percentage of trials with low risk of bias for each domain was as follows: randomisation (33%); allocation concealment (11%); blinding (44%); missing data (49%) and selective reporting (100%). Increasing community demand (32 trials, 10 strategies)The interventions with a statistically significant result were: three trials (n = 64,200) of letter plus leaflet/postcard compared to letter (odds ratio (OR) 1.11, 95% confidence interval (CI) 1.07 to 1.15); two trials (n = 614) of nurses/pharmacists educating plus vaccinating patients (OR 3.29, 95% CI 1.91 to 5.66); single trials of a phone call from a senior (n = 193) (OR 3.33, 95% CI 1.79 to 6.22), a telephone invitation versus clinic drop-in (n = 243) (OR 2.72, 95% CI 1.55 to 4.76), a free groceries lottery (n = 291) (OR 1.04, 95% CI 0.62 to 1.76) and nurses educating and vaccinating patients (n = 485) (OR 152.95, 95% CI 9.39 to 2490.67).We did not pool the following trials due to considerable heterogeneity: postcard/letter/pamphlets (16 trials, n = 592,165); tailored communications (16 trials, n = 388,164); customised letter/phone-call (four trials, n = 82,465) and client-based appraisals (three trials, n = 4016), although several trials showed the interventions were effective. Enhancing vaccination access (10 trials, six strategies)The interventions with a statistically significant result were: two trials (n = 2112) of home visits compared to clinic invitation (OR 1.30, 95% CI 1.05 to 1.61); two trials (n = 2251) of free vaccine (OR 2.36, 95% CI 1.98 to 2.82) and one trial (n = 321) of patient group visits (OR 24.85, 95% CI 1.45 to 425.32). One trial (n = 350) of a home visit plus vaccine encouragement compared to a home visit plus safety advice was non-significant.We did not pool the following trials due to considerable heterogeneity: nurse home visits (two trials, n = 2069) and free vaccine compared to no intervention (two trials, n = 2250). Provider- or system-based interventions (17 trials, 11 strategies)The interventions with a statistically significant result were: two trials (n = 2815) of paying physicians (OR 2.22, 95% CI 1.77 to 2.77); one trial (n = 316) of reminding physicians about all their patients (OR 2.47, 95% CI 1.53 to 3.99); one trial (n = 8376) of posters plus postcards (OR 2.03, 95% CI 1.86 to 2.22); one trial (n = 1360) of chart review/feedback (OR 3.43, 95% CI 2.37 to 4.97) and one trial (n = 27,580) of educational outreach/feedback (OR 0.77, 95% CI 0.72 to 0.81).Trials of posters plus postcards versus posters (n = 5753), academic detailing (n = 1400) and increasing staff vaccination rates (n = 26,432) were non-significant.We did not pool the following trials due to considerable heterogeneity: reminding physicians (four trials, n = 202,264) and practice facilitators (three trials, n = 2183), although several trials showed the interventions were effective. Interventions at the societal level We identified no RCTs of interventions at the societal level.

AUTHORS' CONCLUSIONS

There are interventions that are effective for increasing community demand for vaccination, enhancing access and improving provider/system response. Heterogeneity limited pooling of trials.

Pneumococcal polysaccharide vaccination for adults: new perspectives for Europe

Vaccination is the only public-health measure likely to reduce the burden of pneumococcal diseases. In 2010, a group of European experts reviewed evidence on the burden of pneumococcal disease and the immunogenicity, clinical effectiveness and cost-effectiveness of vaccination with 23-valent pneumococcal polysaccharide vaccine (PPV23). They also considered issues affecting the future use of PPV23 and pneumococcal conjugate vaccines in the elderly and adults at high risk of pneumococcal disease. PPV23 covers 80-90% of the serotypes responsible for invasive pneumococcal disease in Europe. Primary vaccination and revaccination with PPV23 are well tolerated, induce robust, long-lasting immune responses in elderly adults and are cost effective. Ensuring protection against pneumococcal disease requires monitoring of the changing epidemiology of pneumococcal serotypes causing invasive pneumococcal disease and improving vaccine coverage. In the future, it will be critically important for pneumococcal vaccination recommendations for elderly adults to be based on comparative evaluations of PPV23 and newer pneumococcal conjugate vaccines with regard to their long-term immunogenicity, clinical effectiveness and cost-effectiveness.

Immunogenicity and safety of inactivated influenza vaccines in primed populations: a systematic literature review and meta-analysis

Several inactivated influenza vaccine formulations for systemic administration in man are currently available for annual (seasonal) immunization: split virus and subunit (either plain-aqueous, or virosomal, or adjuvanted by MF59). From a literature search covering the period 1978-2009, 33 articles could be identified, which described randomized clinical trials comparing at least two of the four vaccine formulations with respect to serum hemagglutination inhibition (HI) antibody response, local and systemic vaccine reactions and serious adverse events after vaccination, and employing seasonal vaccine components and doses. In total, 9121 vaccinees of all ages, either healthy or with underlying diseases, were involved. Most vaccinees were primed or had been vaccinated in previous years. For immunogenicity, homologous post-vaccination geometric mean HI titers (GMTs) were analyzed by a random effects model for continuous data. Unreported standard deviations (SD) were addressed by imputing assumed SD-values. Age and health state of the vaccinees appeared to have little influence on the outcome. The immunogenicity of split, aqueous and virosomal subunit formulations were similar, with geometric mean ratio values (GMR, quotient of paired GMT-values) varying around one (0.93-1.24). The MF59-adjuvanted subunit vaccine induced, on average, larger antibody titers than the non-adjuvanted vaccine formulations, but the absolute increase was small (GMR-values varying between 1.25 and 1.40). Vaccine reactions were analyzed using a random effects model for binary data. Local and systemic reactogenicity was similar among non-adjuvanted formulations. The adjuvanted subunit formulation was more frequently associated with local reactions than the non-adjuvanted formulations (rate ratio: 2.12, significant). Systemic reactions were similar among all vaccine formulations. The original articles emphasized the mild and transient character of the vaccine reactions and the absence of serious vaccine-related adverse events. This adequate amount of evidence led to the conclusion that all the currently available inactivated influenza vaccine formulations are safe, well tolerated and similarly effective to control seasonal influenza outbreaks across primed populations and age ranges.

Interventions to increase influenza vaccination rates of those 60 years and older in the community

BACKGROUND

Although the evidence to support influenza vaccination is poor, it is promoted by many health authorities. There is uncertainty about the effectiveness of interventions to increase influenza vaccination rates in those 60 years or older.

OBJECTIVES

To assess effects of interventions to increase influenza vaccination rates in those 60 or older.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2010, issue 3), containing the Cochrane Acute Respiratory Infections Group's Specialized Register, MEDLINE (January 1950 to July 2010), PubMed (January 1950 to July 2010), EMBASE (1980 to 2010 Week 28), AgeLine (1978 to July 2010), ERIC (1965 to July 2010) and CINAHL (1982 to July 2010).

SELECTION CRITERIA

Randomized controlled trials (RCTs) to increase influenza vaccination rates in those aged 60 years and older, recording influenza vaccination status either through clinic records, billing data or local/national vaccination registers.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and extracted data.

MAIN RESULTS

Forty-four RCTs were included. All included RCTs studied seniors in the community and in high-income countries. No RCTs of society-level interventions were included. Heterogeneity was marked and meta-analysis was limited. Only five RCTs were graded at low and six at moderate risk of bias. They included three of 13 personalized postcard interventions (all three with the 95% confidence interval (CI) above unity), two of the four home visit interventions (both with 95% CI above unity, but one a small study), three of the four reminder to physicians interventions (none with 95% CI above unity) and three of the four facilitator interventions (one with 95% CI above unity, and one P < 0.01). The other 33 RCTs were at high risk of bias and no recommendations for practice can be drawn.

AUTHORS' CONCLUSIONS

Personalized postcards or phone calls are effective, and home visits, and facilitators, may be effective. Reminders to physicians are not. There is insufficient good evidence for other interventions.

New vaccine approaches for seasonal and pandemic influenza

Inactivated influenza vaccines have been available since the late 1940s for the prevention of influenza disease. Based on the available scientific evidence, many public health authorities, including the World Health Organization, recommend annual use of these vaccines for specific populations, including the elderly. Despite these recommendations, actual vaccination uptake rates are very limited in many countries. Influenza vaccine research is confounded by the variable nature of the influenza viruses and annual influenza epidemics and by non-specific clinical diagnostic criteria. These confounding factors complicate evaluation not only of overall vaccine effectiveness, but also of the relative efficacy and effectiveness of different vaccine formulations. This paper summarizes recent advances in the development of seasonal and (pre-)pandemic vaccines, discusses the methodologic constraints on influenza vaccine research, and proposes measures to reduce the level of potential bias and confounding in influenza vaccine research.

Age-related decline in immunity: implications for vaccine responsiveness

Aging is associated with declines in immune system function, or 'immunosenescence', leading to progressive deterioration in both innate and adaptive immunity. These changes contribute to the decreased response to vaccines seen in many older adults, and morbidity and mortality from infection. Infections (e.g., influenza, pneumonia and septicemia) appear among the top ten most-common causes of death in adults in the USA aged 55 years and older. As immunosenescence has gathered more attention in the scientific and healthcare communities, investigators have demonstrated more links between immunosenescent changes and morbidity and mortality related to infections and declining vaccine responses. This review summarizes the recent literature on age-dependent defects in adaptive and innate immunity, data linking these defects to poor vaccine response and morbidity and mortality, current recommendations for vaccinations and potential strategies to improve vaccine efficacy in older adults.

Influenza and pneumococcal vaccination demand responses to changes in infectious disease mortality

OBJECTIVE

To test the hypothesis that individuals are more likely to receive a vaccination against influenza or pneumonia as the perceived disease threat increases.

DATA SOURCES

This study uses two different national datasets. Individual-level information about the vaccination rates of 38,768 elderly persons are from the Behavioral Risk Factor Surveillance System, 1993-1998. Information on the combined influenza and pneumonia state mortality rates are measured from the Compressed Mortality File.

STUDY DESIGN

Using both cross-sectional and state fixed-effects panel data estimators, we model an individual's probability of having an influenza or pneumococcal vaccination as a function of the lagged state mortality rate. Multiyear lags are specified in order to estimate the duration of the effect of disease mortality on individual vaccination behavior.

PRINCIPAL FINDINGS

Results support our hypothesis that influenza vaccination behavior responds positively to disease mortality, even after a one-year lag. We further find that cross-sectional estimators used in previous work yield downward-biased estimates, although even for our preferred panel data models, the estimated effects are small.

CONCLUSIONS

The findings indicate that behavioral demand responses can help to limit infectious disease epidemics, and suggest further research on how public awareness campaigns can mediate this disease threat responsiveness behavior.

Cost-effectiveness study on influenza prevention in Hong Kong

INTRODUCTION

Recent studies confirm that influenza vaccination confers health benefits and reduces direct and indirect costs associated with the illness. However, these studies did not examine the situation in southern China, a hypothetical influenza epicentre for the emergence of pandemic influenza viruses.

METHODS

Surveillance data were collected in Hong Kong in 1993/94 and used economic model was used to estimate the medical and social costs associated with influenza-like illness (ILI) and to predict the cost-effectiveness of implementing an influenza prevention programme.

FINDINGS

The estimated ILI incidence was 110/1000. It was highest in those between 1 and 25 years of age while the rate of hospitalization was highest in the elderly. Influenza occurred throughout the study period, which was a mild influenza year. The model predicted more than 660000 ILI cases in a non-epidemic year, in which influenza B virus predominated, with an average ILI-associated cost of HK$283/case (US$36) and vaccination-associated costs of HK$74 (US$9.50) per vaccinated individual.

CONCLUSION

The medical, social and monetary costs of ILI in Hong Kong were not observed to be large when compared with those in more developed countries where there is a clearly defined influenza season and recognized disease burden. From the perspective of a susceptible individual, the vaccine was cost-effective but from the perspective of society it was not, even with the most cost-effective strategy of targeting the elderly. However, if the vaccine were effective in controlling newly emerging and highly virulent strains, targeted vaccination programmes might be highly cost-effective.

The cost-effectiveness of a hypothetical respiratory syncytial virus vaccine in the elderly

To determine if specific levels of vaccine cost and effectiveness exist that would support eventual respiratory syncytial virus (RSV) vaccine use in the elderly, a cost-effectiveness study was conducted comparing yearly administration of a hypothetical RSV vaccine among the 65-year-old US cohort to medical management of disease. Using base case assumptions - including a vaccine effectiveness against RSV-related hospitalization and death of 80% and a vaccine cost of US$33 - vaccine would result in 0.7 additional days of healthy life at a cost of US$9.82 per person. The cost per quality-adjusted life-year gained equaled US$5342 and remained reasonable over a wide range of vaccine cost and effectiveness. RSV vaccine would be cost-effective for the elderly population, with cost-effectiveness ratios similar to those for influenza vaccine.

Nursing home-acquired pneumonia

Nursing Home-Acquired Pneumonia is a significant infection that is often seen in the long-term care setting. It is associated with substantial morbidity, healthcare expenditure, and mortality rates as high as 44%. Uniform diagnosis and therapeutic strategies have not been specifically established for pneumonia in the nursing home setting. This paper will update the long-term care provider with the unique features and challenges of pneumonia in this setting and review the approaches to the diagnosis and treatment of this important illness. The discussion will conclude with details regarding overall prevention of nursing home-acquired pneumonia and the critical role played by the nursing home medical director in this process.

Complications of influenza and benefits of vaccination

Uncertainty regarding the benefits of influenza vaccination may contribute to the underutilization of this vaccine. We have conducted serial cohort studies using the administrative data bases of a Twin Cities based managed care organization to assess the impact of disease and benefits of vaccination among the elderly. For the 6 seasons 1990-1991 through 1995-1996, there were more than 20,000 elderly members of the health plan included in each cohort. Data collected included information on baseline demographic and health characteristics, vaccination status and outcomes (hospitalizations and death). Multivariate regression techniques were used to compare the risks of outcomes between vaccinated and unvaccinated persons while controlling for covariates and confounders. Results for data pooled over the 6 seasons demonstrated that influenza vaccination was associated with significant reductions in hospitalizations, outpatient visits, and death among the elderly. Similar findings were observed for low, intermediate, and high risk subgroups. Vaccination was also associated with cost savings. These findings are consistent with results from studies conducted in other countries and over other seasons and strongly support age-based recommendations for annual influenza vaccination for all persons ages 65 and over.

Implications of oral infections on systemic diseases in the institutionalized elderly with a special focus on pneumonia

Systemic infection in the elderly patient living in a chronic care setting presents a significant burden to the health care system. The extent to which oral organisms cause systemic infections through hematogenous dissemination in the institutionalized elderly is still unknown. A more likely and common route of systemic infection by oral microorganisms is through aspiration of oropharyngeal fluids containing oral pathogenic microorganisms, which colonize the lower respiratory tract and cause pneumonia. Respiratory pathogens emerge in the dental plaque of elderly patients with very poor oral hygiene and severe periodontal disease. In the chronic care setting, aspiration of oropharyngeal fluids contaminated with these bacteria occurs in patients with diminished host defenses, resulting in bacterial pneumonia. This is also a problem in intensive care units in the hospital setting. In one study, pre-rinsing with a 0.12% chlorhexidine gluconate mouthwash significantly lowered the mortality rate from postsurgical pneumonia in patients undergoing open heart surgery. Selective digestive decontamination, a technique involving the topical application of antimicrobials to reduce the risk of colonization of the respiratory tract, has been used to reduce the incidence of nosocomial pneumonia in the acute care setting of hospitals. This technique has not been employed in the nursing home setting. Whether improving oral hygiene would also lower the risk in either of these settings has not been studied. A number of obstacles must be overcome in designing studies to investigate the relationship between oral infections and lung infections in the institutionalized elderly. Ethical issues must be addressed, and full collaboration of the medical team is required. Future studies should establish whether reducing the risk for pneumonia in the institutionalized elderly is possible through improved oral health.

Reduction in hospital admissions for pneumonia in non-institutionalised elderly people as a result of influenza vaccination: a case-control study in Spain

OBJECTIVE

To estimate the effectiveness of influenza vaccine in preventing hospital admission for pneumonia in non-institutionalised elderly people.

DESIGN

This was a case-control study.

SETTING

All three public hospitals in the Castellón area of Spain.

PARTICIPANTS

Cases were people aged 65 or more not living in an institution who were admitted to hospital for pneumonia between November 15, 1994 and March 31, 1995. Each case was matched with two sex matched control subjects aged 65 years or older admitted to hospital in the same week for acute abdominal surgical conditions or trauma. The sampling of incident cases was consecutive. Eighty three cases and 166 controls were identified and included in the study.

MEASUREMENTS

Trained interviewers completed a questionnaire for each subject on the vaccination status, smoking habits, previous diseases, health care use, social contacts, family background, the vaccination status of the family carer, home characteristics, and socioeconomic status.

RESULTS

The adjusted odds ratio of the influenza vaccination preventing admission to hospital for pneumonia was 0.21 (95% confidence interval 0.09, 0.55). The variables which best explained the risk of being a case were age, intensity of social contacts, health care use, previous diseases, and the existence of a vaccinated family carer.

CONCLUSIONS

Influenza vaccination reduced significantly hospital admissions for pneumonia in non-institutionalised elderly people.

Genetically engineered live attenuated influenza A virus vaccine candidates

We have generated new influenza A virus live attenuated vaccine candidates by site-directed mutagenesis and reverse genetics. By mutating specific amino acids in the PB2 polymerase subunit, two temperature-sensitive (ts) attenuated viruses were obtained. Both candidates have 38 degrees C shutoff temperatures in MDCK cells, are attenuated in the respiratory tracts of mice and ferrets, and have very low reactogenicity in ferrets. Infection of mice or ferrets with either mutant conferred significant protection from challenge with the homologous wild-type virus. Three tests for genetic stability were used to assess the propensity for reversion to virulence: 14 days of replication in nude mice, growth at 37 degrees C in tissue culture, and serial passage in ferrets. One candidate, which contains mutations intended to reduce the ability of PB2 to bind to cap structures, was stable in all three assays, whereas the second candidate, which contains mutations found only in other ts strains of influenza virus, lost its ts phenotype in the last two assays. This approach has therefore enabled the creation of live attenuated influenza A virus vaccine candidates suitable for human testing.