A case-control study of elderly patients with acute respiratory illness: effect of influenza vaccination on admission to hospital in winter 2003-2004

Every winter, hospitals face a large increase in emergency respiratory admissions in elderly people. A case-control study was undertaken to assess the effect of routine influenza vaccine in preventing such admissions among a cohort of UK elderly presenting with acute respiratory illness during winter 2003-2004. 157 hospitalised cases and 639 controls (matched for age, sex and week of consultation) were interviewed. In a winter typical of levels of circulating influenza in recent years, influenza vaccine did not show a protective effect on emergency respiratory admissions overall (adjusted OR 1.2 (95%CI 0.8, 1.9). Policy makers should not rely solely on influenza vaccine routinely having a large effect on winter pressures, and should focus on additional preventive strategies.     

Influenza vaccination in paediatric nurses: cross-sectional study of coverage, refusal, and factors in acceptance

BACKGROUND: Influenza vaccination among health-care workers is poor, and the effectiveness of hospital vaccination programs remains unclear. Little is known about the effectiveness of intensive evidence-based vaccination programs in nursing staff. We determined whether the recommended vaccination rate could be achieved among paediatric nurses during an intensive promotional program for influenza vaccination. We also sought to identify the reasons for which nurses refuse the influenza vaccine and predictors of future vaccination intent. METHODS: We offered influenza vaccination to nursing staff during an influenza season through a multi-component program that included intensive promotional activities. We analysed vaccination data to determine uptake rates. In a cross-sectional survey, self-administered questionnaires were distributed to all nurses with patient contact during that season. The questionnaire evaluated their vaccine use, site of work, absenteeism and physician visits due to respiratory illness, vaccination intent for the subsequent influenza season, and other items. We surveyed vaccinated nurses regarding their program experiences and the frequency and severity of adverse reactions. Unvaccinated nurses were asked their reasons for refusing vaccination. Multiple logistic-regression analysis was conducted to identify variables that predicted the likelihood of future vaccine acceptance. RESULTS: More than 75% (895/1,182) of applicable nurses were vaccinated in the program. The questionnaire response rate was nearly 48% (585/1,230). Vaccination in the program during the current season (odds ratio [OR] 101.99, 95% confidence interval [CI] 52.54-197.98), program convenience (OR 199.19, 95% CI 98.01-404.11), and a physician visit for respiratory illness (OR 2.44, 95% CI 1.29-4.61) were found to be independent predictors of intent to receive the vaccine the following season. A lack of perceived personal need was the most common reason for vaccine refusal, given in 30% (77/258) of unvaccinated respondents. CONCLUSIONS: Adequate coverage of nurses is achievable during an intensive voluntary immunisation program against influenza, using best-known practices. Perceived lack of personal benefit is a major deterrent, while program convenience and previous vaccination strongly predict future vaccine acceptance. Our findings support interventions that improve the convenience of hospital immunisation programs for influenza, particularly those that are aimed at nurses and that promote vaccine efficacy and benefits.     

Influenza vaccination and risk of hospitalization among adults with laboratory confirmed influenza illness

Background

Influenza vaccine is moderately effective for preventing influenza illness. It is not known if vaccination reduces the risk of subsequent hospital admission among patients with vaccine failure and laboratory confirmed influenza illness.

Methods

Patients in a community cohort presenting with acute respiratory illness were prospectively enrolled and tested for influenza during 8 seasons to estimate seasonal vaccine effectiveness. Hospital admissions within 14 days after illness onset were identified for all participants aged ≥20 years with laboratory confirmed influenza. The association between vaccination and hospital admission was examined in a propensity score adjusted logistic regression model. The model was validated by examining the association between vaccination and hospital admission in participants without influenza.

Results

Influenza was identified in 1393 (28%) of 4996 participants. Sixty-two (6%) of 1020 with influenza A and 17 (5%) of 369 with influenza B were hospitalized. Vaccination was not associated with a reduced risk of hospital admission among all participants with influenza [adjusted odds ratio (aOR) = 1.08; 95% CI: 0.62, 1.88]; or among those with influenza A (aOR = 1.35; 95% CI: 0.71, 2.57) or influenza B (aOR = 0.67; 95% CI: 0.21, 2.15). Influenza vaccination was not associated with hospitalization after non-influenza respiratory illness (aOR = 1.14; 95% CI: 0.84, 1.54).

Conclusions

Influenza vaccination did not reduce the risk of subsequent hospital admission among patients with vaccine failure. These findings do not support the hypothesis that vaccination mitigates influenza illness severity.     

A retrospective survey of the safety of trivalent influenza vaccine among adults working in healthcare settings in south metropolitan Perth, Western Australia, in 2010

In Australia, annual vaccination with trivalent influenza vaccine (TIV) is recommended for healthcare providers. Each year, an influenza vaccination program is run in south metropolitan area hospitals in Perth, Western Australia. In 2010, a survey to examine side effects following vaccination and subsequent significant respiratory illnesses during the influenza season was undertaken. A total of 2245 individuals vaccinated in the area-wide hospital vaccination program responded, representing 50% of consenting recipients. Data linkage was performed to ascertain additional information such as brand details. Side effects within 48 h of receipt of the influenza vaccine were reported by 387 (17.2%). Only 30 respondents (1.3%) had to seek health advice following a side effect temporally related to influenza vaccination and 10 (0.4%) required treatment. Recipients who received Fluvax^® (364, 18.0%; CSL Biotherapies) were more likely to report side effects than those who received another brand (23, 10.2%; OR 1.94, 95% CI 1.24–3.03, P = 0.004). The difference in the side effect profiles was largely confined to systemic effects. Most respondents (1621, 72.2%) did not require time off work for a respiratory illness during the subsequent influenza season. Overall, the influenza vaccine was demonstrated to be safe among this large sample of predominantly healthcare workers. A higher rate of adverse events, albeit primarily mild, was reported among recipients of Fluvax^® in 2010.     

Effectiveness of seasonal trivalent influenza vaccination against hospital-attended acute respiratory infections in pregnant women: A retrospective cohort study

BackgroundPregnant women are at risk of serious influenza infection. Although previous studies indicate maternal influenza vaccination can prevent hospitalisation in young infants, there is limited evidence of the effect in mothers.MethodsA cohort of 34,701 pregnant women delivering between 1 April 2012 and 31 December 2013 was created using birth records. Principal diagnosis codes from hospital emergency department (ED) and inpatient records were used to identify episodes of acute respiratory illness (ARI) during the 2012 and 2013 southern hemisphere influenza seasons. Cox regression models were used to calculate adjusted hazard ratios (aHRs) by maternal vaccination status, controlling for Indigenous status, socioeconomic level, medical conditions, and week of delivery.Results3,007 (8.7%) women received a seasonal influenza vaccine during pregnancy. Vaccinated women were less likely to visit an ED during pregnancy for an ARI (9.7 visits per 10,000 person-days vs. 35.5 visits per 10,000 person-days; aHR: 0.19, 95% CI: 0.05−0.68). Vaccinated women were also less likely to be hospitalised with an ARI compared to unvaccinated women (16.2 hospitalisations per 10,000 person-days vs. 34.0 hospitalisations per 10,000 person-days; aHR: 0.35, 95% CI: 0.13−0.97).ConclusionsInfluenza vaccination during pregnancy was associated with significantly fewer hospital attendances for ARI in pregnant women.     

Moving the needle on nursing staff influenza vaccination in long-term care: Results of an evidence-based intervention

PurposeInfluenza vaccination rates among healthcare providers (HCPs) in long-term care facilities (LTCFs) are commonly below the Healthy People 2020 goal of 90%. This study was conducted to develop and evaluate an intervention program designed to increase influenza uptake among HCPs in LTCFs.MethodsThis study was conducted in four Midwestern LTCFs. Baseline interviews, surveys, and administrative data analysis were performed following the 2013–2014 influenza season. Interventions implemented during the 2014–2015 season were based on the health belief and ecological models and included goal-setting worksheets, policy development, educational programs, kick-off events, incentives, a vaccination tracking roster, and facility-wide communication about vaccine uptake among HCPs. Outcomes were evaluated in 2015.ResultsAt baseline, 50% of 726 nursing staff employed during the 2013–2014 influenza season had documented receipt of influenza vaccine (Site A: 34%; Site B: 5%; Site C: 75%; Site D: 62%), and 31% of 347 survey respondents reported absenteeism due to respiratory illness. At follow-up, 85% of HCPs had documented receipt of influenza vaccine (p < 0.01) and 19% of 323 survey respondents reported absenteeism due to respiratory illness (p < 0.01). Vaccination rates among respondents’ family members increased from 31% at baseline to 44% post-intervention (p < 0.01). Reasons for declining vaccination did not change following exposure to educational programs, but HCPs were more likely to recommend vaccination to others after program implementation.ConclusionsVaccination rates among long-term care HCPs and their family members increased significantly and HCP absenteeism decreased after the implementation of multifaceted interventions based on an ecological model. The findings suggest that major increases in HCP vaccination can be achieved in LTCFs. More research is needed to evaluate the impact of increased HCP vaccination on the health and productivity of LTCF employees, their family members, and residents.     

Intent to obtain pediatric influenza vaccine among mothers in four middle income countries

BackgroundDespite a large burden of influenza in middle income countries, pediatric vaccination coverage remains low. The aims of this study were to (1) describe mothers’ knowledge and attitudes about influenza illnesses and vaccination, and (2) identify characteristics associated with mothers’ intent to vaccinate their child.MethodsFrom 2015 to 2017, infants 0–11 months old in Nicaragua, Philippines, Jordan, and Albania were enrolled from community settings and hospitals. Interviewers administered a questionnaire to their mothers. Mothers of infants aged 6–11 months rated their intention (small-to-moderate vs. large chance) to accept pediatric vaccination if it was offered at no-cost. The importance of knowledge, attitudes, and sociodemographic characteristics in predicting influenza vaccination intention was measured as the mean decrease in Gini index when that factor was excluded from 1000 decision trees in a random forest analysis.ResultsIn total, 1,308 mothers were enrolled from the community setting and 3,286 from the hospital setting. Prevalence of at least some knowledge of influenza illness ranged from 34% in Philippines to 88% in Albania (in the community sample), and between 23% in Philippines to 88% in Jordan (in the hospital sample). In the community sample, most mothers in Albania (69%) and Philippines (58%) would accept the influenza vaccine, and these proportions were higher in the hospital sample for all countries except Albania (48%) (P < 0.0001). Perceived vaccine safety (mean decrease in Gini index = 61) and effectiveness (55), and perceived knowledge of influenza vaccine (45) were the most important predictors of influenza vaccination intention in models that also included country and community versus hospital sample.ConclusionIntent to vaccinate infants aged 6–11 months in four middle income countries was tied primarily to knowledge of the vaccine and perceptions of vaccine safety and effectiveness. These findings were noted among mothers interviewed in the community and mothers of recently hospitalized infants.     

Factors influencing influenza vaccination rates among healthcare workers in Greek hospitals

Influenza vaccination rates are generally low among healthcare workers (HCWs) worldwide. In September 2005, the Hellenic Center for Disease Control and Prevention conducted a nationwide campaign to promote influenza vaccination in hospital HCWs. During the 2005-2006 influenza season, the overall vaccination rate among HCWs was 16.36% (range: 0-85.96%). The self-reported vaccination rate during the previous season was 1.72%, indicating a 9.5-fold increase. Compared with physicians, significantly fewer technical personnel were vaccinated, whereas administrative personnel were more likely to receive the vaccine. Among clinicians, rates for internal medicine departments exceeded those of surgical departments by a factor of 2.71 and laboratory medicine departments by a factor of 2.36. Multivariate analysis showed lower vaccination rates in large hospitals (>200 beds) than in smaller hospitals and lower rates in hospitals with specialist services (intensive care unit, psychiatry or dermatology) than in general hospitals. Factors associated with higher rates included working in northern Greece, in a paediatric or an oncology hospital, or in a prefecture with avian influenza H5N1 activity. In conclusion, in Greece influenza vaccination rates among HCWs remain low, but the implementation of a nationwide campaign had a considerable impact. Efforts should focus on hospital- and HCW-associated factors to increase vaccination uptake.     

Lessons from 40 years' surveillance of influenza in England and Wales

The influenza virus continues to pose a significant threat to public health throughout the world. Current avian influenza outbreaks in humans have heightened the need for improved surveillance and planning. Despite recent advances in the development of vaccines and antiviral drugs, seasonal epidemics of influenza continue to contribute significantly to general practitioner workloads, emergency hospital admissions, and deaths. In this paper we review data produced by the Royal College of General Practitioners Weekly Returns Service, a sentinel general practice surveillance network that has been in operation for over 40 years in England and Wales. We show a gradually decreasing trend in the incidence of respiratory illness associated with influenza virus infection (influenza-like illness; ILI) over the 40 years and speculate that there are limits to how far an existing virus can drift and yet produce substantial new epidemics. The burden of disease caused by influenza presented to general practitioners varies considerably by age in each winter. In the pandemic winter of 1969/70 persons of working age were most severely affected; in the serious influenza epidemic of 1989/90 children were particularly affected; in the millennium winter (in which the NHS was severely stretched) ILI was almost confined to adults, especially the elderly. Serious confounders from infections due to respiratory syncytial virus are discussed, especially in relation to assessing influenza vaccine effectiveness. Increasing pressure on hospitals during epidemic periods are shown and are attributed to changing patterns of health-care delivery.     

Preventing nosocomial influenza by improving the vaccine acceptance rate of clinicians.

OBJECTIVES: To assess the effects of interventions to prevent transmission of influenza and to increase employee compliance with influenza vaccination. DESIGN: The change in the proportion of hospitalized patients with laboratory-confirmed nosocomial influenza was observed over time and assessed using chi-square for trend analysis. The association between nosocomial influenza in patients and healthcare worker (HCW) compliance with vaccine was assessed by logistic regression. SETTING: A 600-bed, tertiary-care academic hospital. METHODS: After an outbreak of influenza A at this hospital in 1988, a mobile cart program was instituted with increased efforts to motivate employees to be vaccinated and furloughed when ill as well as new measures to prevent nosocomial spread. RESULTS: HCW vaccination rates increased from 4% in 1987-1988 to 67% in 1999-2000 (P < .0001). Proportions of nosocomially acquired influenza cases among employees or patients both declined significantly (P < .0001). Logistic regression analysis revealed a significant inverse association between HCW compliance with vaccination and the rate of nosocomial influenza among patients (P < .001). CONCLUSION: A mobile cart vaccination program and an increased emphasis on HCWs to receive the vaccine were associated with a significant increase in vaccine acceptance and a significant decrease in the rate of nosocomial influenza among patients.     

Survey on use of and attitudes toward influenza vaccination among emergency department staff in a New York metropolitan hospital.

OBJECTIVE: Recognizing that the potential transmission of influenza virus would be concentrated at a hospital's primary point of entry, we determined rates of staff compliance with the influenza vaccination recommendations of the Advisory Committee on Immunization Practices (ACIP) in the Emergency Department (ED). We describe the basic knowledge concerning influenza transmission and factors influencing vaccination decisions among ED staff. DESIGN: Cross-sectional study. SETTING AND PARTICIPANTS: A large urban teaching hospital. Participants included ED staff, visiting professionals from other departments, and emergency medical service personnel transferring patients to the hospital. RESULTS: Of 230 surveys that were distributed, 200 were completed. One hundred one respondents (51%) were female. The overall influenza vaccination rate was 50%. Having had influenza previously was the most instrumental factor in whether or not a respondent chose vaccination (P<.001). Use of the Employees Health Services Free Vaccine Program (FVP) was a very important factor influencing whether ED staff sought influenza vaccination (P<.0001). Prior knowledge of the ACIP recommendations proved to be not statistically important (P=.03). A significant factor for respondents declining vaccination was the concern that illness could be caused by the vaccine (P<.0001). Variables such as sex of the respondents (P=.6714) and type of job (P=.3628) were not associated with vaccination. CONCLUSION: Despite ACIP recommendations, 50% of respondents did not receive an influenza vaccination. Misconceptions regarding influenza vaccine efficacy, concerns about adverse effects, and fear of contracting illness were significantly associated with noncompliance with vaccination. Variables that were important contributors to compliance with vaccination were prior influenza illness and services rendered by the FVP.     

Effect of a hospital campaign for influenza vaccination of healthcare workers.

OBJECTIVE: To identify the factors that inhibit or motivate influenza vaccination among healthcare workers (HCWs). METHODS: In March 2000, we prepared 34-item questionnaire for both vaccine recipients and nonrecipients regarding demographic characteristics, factors motivating and inhibiting vaccination, and knowledge and attitudes about influenza vaccination. On the basis of the results of our survey, an aggressive hospital vaccination campaign was undertaken. In April 2004, after the 4-year campaign, the same questionnaire was again administered to HCWs. RESULTS: In both 2000 and 2004, the main motives for undergoing influenza vaccination were "hospital campaign" and "recommendation by colleagues"; the percentage of respondents who were motivated by the hospital campaign had remarkably increased from 27% in 2000 to 52% in 2004 (P<.001), whereas the percentage who were motivated by recommendation by colleagues had not changed significantly (21% vs 14%). Overall, the 4 reasons most frequently cited by HCWs for noncompliance with vaccination were insufficient available time, confidence in their health, doubt about vaccine efficacy, and fear of injection. In 2000, vaccination rates were below 30%, irrespective of occupation. After an aggressive vaccination campaign, the increase in the vaccination rate was highest among the nursing staff, increasing from 21% in 2000 to 92% in 2004, whereas the vaccination rate among the physicians was still below 60%. CONCLUSION: We conclude that a hospital campaign can markedly improve influenza vaccination rates among HCWs. Both a mobile cart system and free vaccine supply contributed to improving the vaccination rates in our study. In addition, a specifically tailored intervention strategy was required.     

Effectiveness of influenza vaccine in reducing hospital admissions during the 1989-90 epidemic.

The effectiveness of influenza vaccine in reducing hospital admissions for pneumonia, influenza, bronchitis, or emphysema was assessed by a case-control study of people aged 16 years and older who were admitted to 10 Leicestershire hospitals between 1 December 1989 and 31 January 1990. Hospital and general practitioners'' records for 156 admissions (the cases) and 289 controls matched for age and sex were reviewed. Information was collected on demography, the usual place of residence (institutional or non-institutional), the existence of chronic illness, and vaccination during the 5 years before admission. The odds ratio for hospital admission among vaccinees was 0.67 (95% CI 0.39-1.12) giving an estimate of vaccine effectiveness in this setting of 33% (95% CI 0-61). However, multivariate logistic regression, adjusting for the effects of institutional care and chronic illness, revealed that influenza vaccination reduced hospital admissions by 63% (95% CI 17-84%). There was a strong trend towards improved vaccine effectiveness when used in institutional settings. Influenza vaccine is effective in reducing hospital admissions for influenza, pneumonia, bronchitis and emphysema, and effectiveness is comparable to that observed for influenza and pneumonia admissions in North America.     

Influenza vaccination in pregnancy: current practices in a suburban community

PURPOSE: The Centers for Disease Control (CDC) identify women in their second and third trimesters as a high-risk population warranting influenza vaccination. This study attempted to characterize understanding of these guidelines and obstacles to their implementation in a suburban community. METHODS: Family physicians and obstetricians with admitting privileges to a community-based hospital were surveyed regarding estimated vaccine availability and administration in their practices and regarding knowledge of indications and contraindications to influenza vaccination in pregnancy. RESULTS: Of the 20 obstetricians and 66 family physicians completing the survey, 68.4% of obstetricians and 90.5% of family physicians carried the vaccine in their offices (P =.027). Both obstetricians and family physicians incorrectly perceived multiple factors as contraindications to influenza vaccination in pregnancy. Obstetricians and family physicians reported similar proportions of their pregnant patients received the vaccine (35 versus 40%). CONCLUSIONS: In this study, more family physicians had the influenza vaccine available than obstetricians, but there was no difference in estimated rates of vaccination during pregnancy or in the understanding of its indications and contraindications. Finally, no physicians in our community reported providing influenza vaccination in pregnancy at recommended frequencies. Further research is needed to clarify methods of improving vaccination rates in both family practice and obstetric settings.     

Influenza vaccine effectiveness among elderly persons living in the community during the 2003--2004 season

To examine the effectiveness of influenza vaccine among community-dwelling elderly (65-79 years old), we conducted a population-based cohort study during the 2003--2004 influenza season. A total of 4787 elderly individuals were interviewed regarding acute febrile illness, hospital visits, hospitalization and death by telephone every month. The vaccination status and physician-diagnosed clinical influenza (hereinafter referred as clinical influenza) were determined based on data obtained from the city office and hospitals, respectively. After adjusting for confounders, the odds ratio (OR) of vaccination for influenza-like illness (ILI) with high-fever, which was defined as an acute febrile illness (> or =38.5 degrees C) during the epidemic period, was 0.38 (95% confidence interval [CI], 0.17-0.85) and the OR for clinical influenza was 0.76 (95%CI, 0.28-2.06). Due to the inadequate sample size, ORs for preventing hospitalization for influenza or pneumonia (OR, 0.37; 95%CI, 0.09-1.47) and death (OR, 3.68; 95%CI, 0.75-18.12) were not conclusive. These results suggested that vaccination was therefore effective for elderly persons living in the community.     

Influenza vaccination in long-term-care facilities: structuring programs for success.

OBJECTIVES: To determine which influenza vaccination program characteristics were associated with high resident vaccination rates in Canadian long-term-care facilities (LTCFs). DESIGN: A cross-sectional survey consisting of a mailed questionnaire conducted in spring 1991. PARTICIPANTS: All 1,520 Canadian LTCFs for the elderly with at least 25 beds. RESULTS: The mean overall influenza vaccination rate in the 1,270 (84%) responding facilities was 79%. In multivariate analysis, the variables significantly associated with increased vaccination rates were: a single nonphysician staff person organizing the program, having more program aspects covered by written policies, the offering of vaccine to all residents, a policy of obtaining consent on admission that was durable for future years rather than repeating consent annually, and automatically administering vaccine to residents whose guardians could not be contacted for consent. Any encouragement to staff to be vaccinated had a significant impact on staff vaccination rates. CONCLUSION: Well-organized influenza vaccination programs increase the influenza vaccination rates of residents in Canadian LTCFs. Facilities need to develop resident vaccination programs further and to focus on vaccinating staff.     

Influenza vaccine acceptance and hesitancy among adults hospitalized with severe acute respiratory illnesses,United States 2019–2020

IntroductionUnderstanding patient factors associated with not being vaccinated is essential for successful implementation of influenza vaccination programs.MethodsWe enrolled adults hospitalized with severe acute respiratory illness at 10 United States (US) hospitals during the 2019–2020 influenza season. We interviewed patients to collect data about influenza vaccination, sociodemographic characteristics, and vaccine perceptions.ResultsAmong 679 participants, 264 (38.9%) reported not receiving influenza vaccination. Among those not vaccinated, 135 (51.1%) reported choosing not to receive a vaccine because of perceived ineffectiveness (36.7%) or risk (14.4%) of influenza vaccination. Sociodemographic factors associated with not being vaccinated included no medical insurance (aOR = 6.42; 95% CI: 2.52–16.38) and being non-White or Hispanic (aOR = 1.54, 95% CI: 1.02–2.32).ConclusionsOptimizing uptake of influenza vaccination in the US may be improved by educational programs regarding vaccine safety and effectiveness and enhancing vaccine access, particularly among non-White and Hispanic Americans and those without medical insurance.     

Influenza vaccination and respiratory virus interference among Department of Defense personnel during the 2017–2018 influenza season

PurposeReceiving influenza vaccination may increase the risk of other respiratory viruses, a phenomenon known as virus interference. Test-negative study designs are often utilized to calculate influenza vaccine effectiveness. The virus interference phenomenon goes against the basic assumption of the test-negative vaccine effectiveness study that vaccination does not change the risk of infection with other respiratory illness, thus potentially biasing vaccine effectiveness results in the positive direction. This study aimed to investigate virus interference by comparing respiratory virus status among Department of Defense personnel based on their influenza vaccination status. Furthermore, individual respiratory viruses and their association with influenza vaccination were examined.ResultsWe compared vaccination status of 2880 people with non-influenza respiratory viruses to 3240 people with pan-negative results. Comparing vaccinated to non-vaccinated patients, the adjusted odds ratio for non-flu viruses was 0.97 (95% confidence interval (CI): 0.86, 1.09; p = 0.60). Additionally, the vaccination status of 3349 cases of influenza were compared to three different control groups: all controls (N = 6120), non-influenza positive controls (N = 2880), and pan-negative controls (N = 3240). The adjusted ORs for the comparisons among the three control groups did not vary much (range: 0.46–0.51).ConclusionsReceipt of influenza vaccination was not associated with virus interference among our population. Examining virus interference by specific respiratory viruses showed mixed results. Vaccine derived virus interference was significantly associated with coronavirus and human metapneumovirus; however, significant protection with vaccination was associated not only with most influenza viruses, but also parainfluenza, RSV, and non-influenza virus coinfections.     

Effectiveness of the MF59-adjuvanted influenza vaccine in preventing emergency admissions for pneumonia in the elderly over 64 years of age

Case–control study designed to determine the effectiveness of an MF59-adjuvanted influenza vaccine in the population aged 65 years and older living in the community. Detailed health histories were obtained on both cases and controls that included a functional measure of co-morbidity (Barthel Index). Subjects were all eligible persons admitted to various hospitals with a diagnosis of pneumonia during the winter months and were matched by sex, hospital and admission week to controls admitted for non-medical reasons. The influenza vaccination programme using the MF59-adjuvanted influenza vaccine significantly reduced the probability of being hospitalised for pneumonia in the elderly over 64 years of age, even in a season with a low influenza activity, during which the predominant circulating strains were types B and A (H1N1).