Influenza vaccination: policy versus evidence.
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ABSTRACT:
SUBMITTER: Jefferson T
PROVIDER: S-EPMC1626345 | biostudies-literature | 2006 Oct
REPOSITORIES: biostudies-literature
Publications
Influenza vaccination: policy versus evidence.
BMJ (Clinical research ed.) 20061001 7574
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Project description:IntroductionThe World Health Organization recommends vaccination of health workers (HWs) against influenza, but low uptake is intransigent.We conducted a Rapid Evidence Appraisal on: the risk of influenza in HWs, transmission risk from HWs to patients, the benefit of HW vaccination, and strategies for improving uptake. We aimed to capture a 'whole-of-system' perspective to consider possible benefits for HWs, employers and patients.MethodsWe executed a comprehensive search of the available literature published from 2006 to 2018 in the English language. We developed search terms for seven separate questions following the PICO framework (population, intervention, comparators, outcomes) and queried nine databases.ResultsOf 3784 publications identified, 52 met inclusion criteria. Seven addressed HW influenza risk, of which four found increased risk; 15 addressed influenza vaccine benefit to HWs or their employers, of which 10 found benefit; 11 addressed influenza transmission from HWs to patients, of which 6 found evidence for transmission; 12 unique studies addressed whether vaccinating HWs produced patient benefit, of which 9 concluded benefits accrued. Regarding the number of HWs needed to vaccinate (NNV) to deliver patient benefit, NNV estimates ranged from 3 to 36,000 but were in significant disagreement. Fourteen studies provided insights on strategies to improve uptake; the strongest evidence was for mandatory vaccination.ConclusionsThe evidence on most questions related to influenza vaccination in HWs is mixed and often of low-quality. Substantial heterogeneity exists in terms of study designs and settings, making comparison between studies difficult. Notwithstanding these limitations, a majority of studies suggests that influenza vaccination benefit HWs and their employers; and HWs are implicated in transmission events. The effects of vaccinating HWs on patient morbidity and mortality may include reductions in all-cause mortality and influenza-like illness (ILI). Taken together, the evidence suggests that HW vaccination is an important policy for HWs themselves, their employers, and their patients.
| S-EPMC6668237 | biostudies-literature
Project description:Theoretical models of infection spread on networks predict that targeting vaccination at individuals with a very large number of contacts (superspreaders) can reduce infection incidence by a significant margin. These models generally assume that superspreaders will always agree to be vaccinated. Hence, they cannot capture unintended consequences such as policy resistance, where the behavioral response induced by a new vaccine policy tends to reduce the expected benefits of the policy. Here, we couple a model of influenza transmission on an empirically-based contact network with a psychologically structured model of influenza vaccinating behavior, where individual vaccinating decisions depend on social learning and past experiences of perceived infections, vaccine complications and vaccine failures. We find that policy resistance almost completely undermines the effectiveness of superspreader strategies: the most commonly explored approaches that target a randomly chosen neighbor of an individual, or that preferentially choose neighbors with many contacts, provide at best a 2% relative improvement over their non-targeted counterpart as compared to 12% when behavioral feedbacks are ignored. Increased vaccine coverage in super spreaders is offset by decreased coverage in non-superspreaders, and superspreaders also have a higher rate of perceived vaccine failures on account of being infected more often. Including incentives for vaccination provides modest improvements in outcomes. We conclude that the design of influenza vaccine strategies involving widespread incentive use and/or targeting of superspreaders should account for policy resistance, and mitigate it whenever possible.
| S-EPMC3591296 | biostudies-literature
Project description:Influenza vaccination is the primary approach to prevent influenza annually. WHO/CDC recommendations prioritize vaccinations mainly on the basis of age and co-morbidities, but have never considered influenza infection history of individuals for vaccination targeting. We evaluated such influenza vaccination policies through small-world contact networks simulations. Further, to verify our findings we analyzed, independently, large-scale empirical data of influenza diagnosis from the two largest Health Maintenance Organizations in Israel, together covering more than 74% of the Israeli population. These longitudinal individual-level data include about nine million cases of influenza diagnosed over a decade. Through contact network epidemiology simulations, we found that individuals previously infected with influenza have a disproportionate probability of being highly connected within networks and transmitting to others. Therefore, we showed that prioritizing those previously infected for vaccination would be more effective than a random vaccination policy in reducing infection. The effectiveness of such a policy is robust over a range of epidemiological assumptions, including cross-reactivity between influenza strains conferring partial protection as high as 55%. Empirically, our analysis of the medical records confirms that in every age group, case definition for influenza, clinical diagnosis, and year tested, patients infected in the year prior had a substantially higher risk of becoming infected in the subsequent year. Accordingly, considering individual infection history in targeting and promoting influenza vaccination is predicted to be a highly effective supplement to the current policy. Our approach can also be generalized for other infectious disease, computer viruses, or ecological networks.
| S-EPMC4031061 | biostudies-literature
Project description:The recent threat of bioterrorism has fueled debate on smallpox vaccination policy for the United States. Certain policy proposals call for voluntary mass vaccination; however, if individuals decide whether to vaccinate according to self-interest, the level of herd immunity achieved may differ from what is best for the population as a whole. We present a synthesis of game theory and epidemic modeling that formalizes this conflict between self-interest and group interest and shows that voluntary vaccination is unlikely to reach the group-optimal level. This shortfall results in a substantial increase in expected mortality after an attack.
| S-EPMC193525 | biostudies-literature
Project description:BackgroundWe assessed the impact of two major modifications of the Dutch National Influenza Prevention Programme--the introduction in 1997 of free-of-charge vaccination to persons aged ≥65 years and to high-risk groups (previously only advised, and not free of charge), and the lowering of the eligible age to 60 years in 2008--on the estimated incidence of influenza infection leading to influenza-like illness (ILI).MethodsAdditive negative-binomial segmented regression models were fitted to ILI data from GP sentinel surveillance in two-eight-season intervals (1993/4 to 2000/1, 2004/5 to 2011/12, comparing pre- and post-policy-change periods within each interval), with laboratory virological reporting of samples positive for influenza or other ILI-causing pathogens as covariates.ResultsFor the 2008 policy change, there was a significant step decrease in influenza contribution considering all ages (=-111 per 100 positives; 95% CI: -162, -65·0), <60 years and 60-64 years age groups (B = -92·1 per 100; 95% CI: -134, -55·5; B = -5·2; 95% CI: -10·3, -1·2, respectively). There was no evidence for a decrease associated with the 1997 policy change targeting the ≥65 years age group.ConclusionsIn the Netherlands, a 56% reduction in influenza contribution was associated with the 2008 policy targeting 60-64 year-olds, but there was no effect of the earlier policy targeting ≥65-year-olds, for whom vaccination coverage was already rising before the policy change.
| S-EPMC4746562 | biostudies-literature
Project description:Whole blood transcriptomics analysis of healthy individuals, immunized with the trivalent 2012-2013 season flu vaccine via transcutaneous, intramuscular or intradermal route. We define an early gene expression profile, detected at day 1 after immunization, that is associated with the development of either humoral or cytotoxic CD8 T cell responses. We used System Biology approach to analyse vaccine efficacy in order to find innate predictive biomarkers of the quality of adaptive responses for potential clinical use in the future. Moreover, from a methodological point of view this study increases knowledges on how vaccine route(s) can affect resulting immune responses and into mechanisms involved in the induction of humoral and cellular immunity to influenza vaccination.
2019-07-01 | E-MTAB-7741 | biostudies-arrayexpress
Project description:BackgroundSystems vaccinology allows cutting-edge analysis of innate biomarkers of vaccine efficacy. We have been exploring novel strategies to shape the adaptive immune response, by targeting innate immune cells through novel immunization routes.MethodsThis randomized phase I/II clinical study (n=60 healthy subjects aged 18-45 years old) used transcriptomic analysis to discover early biomarkers of immune response quality after transcutaneous (t.c.), intradermal (i.d.), and intramuscular (i.m.) administration of a trivalent influenza vaccine (TIV season 2012-2013) (1:1:1 ratio). Safety and immunogenicity (hemagglutinin inhibition (HI), microneutralization (MN) antibodies and CD4, CD8 effector T cells) were measured at baseline Day (D)0 and at D21. Blood transcriptome was analyzed at D0 and D1.ResultsTIV-specific CD8+GranzymeB+(GRZ) T cells appeared in more individuals immunized by the t.c. and i.d. routes, while immunization by the i.d. and i.m. routes prompted high levels of HI antibody titers and MN against A/H1N1 and A/H3N2 influenza viral strains. The early innate gene signature anticipated immunological outcome by discriminating two clusters of individuals with either distinct humoral or CD8 cytotoxic responses. Several pathways explained this dichotomy confirmed by nine genes and serum level of CXCL10 were correlated with either TIV-specific cytotoxic CD8+GRZ+ T-cell or antibody responses. A logistic regression analysis demonstrated that these nine genes and serum levels of CXCL10 (D1/D0) best foreseen TIV-specific CD8+GRZ+ T-cell and antibody responses at D21.ConclusionThis study provides new insight into the impact of immunization routes and innate signature in the quality of adaptive immune responses.
| S-EPMC6486343 | biostudies-literature
Project description:BackgroundSome studies have found a higher frequency of fever with trivalent live attenuated influenza vaccine (LAIV) than with inactivated influenza vaccine (IIV), but quadrivalent LAIV has not been assessed. Understanding fever is important for safety reviews and for parents and providers. In addition, there have been only a limited number of studies in which text messaging was used for vaccine adverse-event (AE) surveillance.MethodsWe conducted a prospective observational study in 3 community clinics in New York City to assess post-influenza vaccination fever in 24- to 59-month-olds during the 2013-2014 season. Enrolled families of children who received quadrivalent LAIV (LAIV4) or IIV (trivalent IIV3 or quadrivalent IIV4) replied to text messages that assessed their temperature on vaccination night and the next 10 nights (days 0 to 10); missing data were collected via telephone and a diary. We compared frequencies of fever (temperature ≥ 100.4°F) according to vaccine group on days 0 to 2 and 3 to 10 by using χ2 and multivariate log-binomial regression adjusted for age, previous influenza vaccination, and vaccine coadministration. We also assessed outcomes using all sources versus only text messages.ResultsMost (84.1% [n = 540]) eligible parents enrolled. Fever frequencies on days 0 to 2 did not differ between LAIV4 and any IIV (3.8% vs 5.7%, respectively; adjusted relative risk [aRR] [95% confidence interval], 0.60 [0.25-1.46]), between LAIV4 and IIV4 (4.2% vs 7.1%, respectively; aRR, 0.58 [0.19-1.72]), or between IIV4 and IIV3 (7.1% vs 6.0%, respectively; aRR, 1.02 [0.30-3.46]). The findings were similar when all data sources versus text-message data alone were used. There were no significant differences on days 3 to 10.ConclusionsPostvaccination fever frequencies were low overall and did not differ according to influenza vaccine type during the 2013-2014 influenza season. The similarity of results when data were limited to text messages lends support to its use for surveillance of vaccine adverse events.
| S-EPMC6675416 | biostudies-literature
Project description:BackgroundMost countries recommend that healthcare workers (HCWs) are vaccinated seasonally against influenza in order to protect themselves and patients. However, in many cases coverage remains low. A range of strategies have been implemented to increase uptake. Qualitative evidence can help in understanding the context of interventions, including why interventions may fail to achieve the desired effect. This study aimed to synthesise evidence on HCWs' perceptions and experiences of vaccination for seasonal influenza.MethodsSystematic review of qualitative evidence. We searched MEDLINE, EMBASE and CINAHL and included English-language studies which reported substantive qualitative data on the vaccination of HCWs for seasonal influenza. Findings were synthesised thematically.ResultsTwenty-five studies were included in the review. HCWs may be motivated to accept vaccination to protect themselves and their patients against infection. However, a range of beliefs may act as barriers to vaccine uptake, including concerns about side-effects, scepticism about vaccine effectiveness, and the belief that influenza is not a serious illness. HCWs value their autonomy and professional responsibility in making decisions about vaccination. The implementation of interventions to promote vaccination uptake may face barriers both from HCWs' personal beliefs and from the relationships between management and employees within the targeted organisations.ConclusionsHCWs' vaccination behaviour needs to be understood in the context of HCWs' relationships with each other, with management and with patients. Interventions to promote vaccination should take into account both the individual beliefs of targeted HCWs and the organisational context within which they are implemented.
| S-EPMC5688738 | biostudies-literature
Project description:ObjectivesDespite continuous efforts to improve influenza vaccination coverage, uptake among high-risk groups remains suboptimal. We aimed to identify policy amenable factors associated with vaccination and to measure their importance in order to assist in the monitoring of vaccination sentiment and the design of communication strategies and interventions to improve vaccination rates.SettingThe USA, the UK and France.ParticipantsA total of 2412 participants were surveyed across the three countries.Outcome measuresSelf-reported influenza vaccination.MethodsBetween March and April 2014, a stratified random sampling strategy was employed with the aim of obtaining nationally representative samples in the USA, the UK and France through online databases and random-digit dialling. Participants were asked about vaccination practices, perceptions and feelings. Multivariable logistic regression was used to identify factors associated with past influenza vaccination.ResultsThe models were able to explain 64%-80% of the variance in vaccination behaviour. Overall, sociopsychological variables, which are inherently amenable to policy, were better at explaining past vaccination behaviour than demographic, socioeconomic and health variables. Explanatory variables included social influence (physician), influenza and vaccine risk perceptions and traumatic childhood experiences.ConclusionsOur results indicate that evidence-based sociopsychological items should be considered for inclusion into national immunisation surveys to gauge the public's views, identify emerging concerns and thus proactively and opportunely address potential barriers and harness vaccination drivers.
| S-EPMC5734251 | biostudies-literature