Cost-effectiveness of vaccination versus treatment of influenza in healthy adolescents and adults

Respiratory Infections

Pneumonia is one of the most common reasons for health care utilization in the United States. It can be caused by many different pathogens, but rarely is it able to be identified in specific cases. This has led most racial disparities research to focus on community acquired pneumonia and microbes of public health concern such as influenza, tuberculosis, and COVID-19. Differences have been shown to exist from prevention with vaccines to management and outcomes. COVID-19 has led to a significant increase in the awareness of this topic.

COVID-19 Anti-Vaccine Sentiments in Malaysia: Narratives of Comments from Facebook Post

The anti-vaccination movement was an ongoing issue in Malaysia, a Muslim-majority country, even before the COVID-19 pandemic. It is unclear whether the introduction of new COVID-19 vaccines would similarly provoke anti-vaccine sentiments. This study analyzed COVID-19 anti-vaccine sentiments in the Malaysian community. Anti-vaccine comments from Facebook page posts were extracted. The qualitative software QSR-NVivo 10 was used to manage, code and analyze the data. The fast-track COVID-19 vaccine evoked the fear of unknown long-term effects, safety, effectiveness and the duration of protection. The halal status of the COVID-19 vaccines is important. Although it is permissible to use vaccines that are not certified halal under the state of darurah (emergency), there was doubt that the current state has reached the stage of darurah that warrants the use of vaccines. COVID-19 vaccine microchip conspiracy theories were raised. COVID-19 is viewed as only severe for vulnerable populations, and hence vaccination is not needed for the healthy. There were opinions that coronavirus treatments would be more beneficial than vaccination. The anti-COVID-19 vaccine sentiments uncovered in this study provide important insights for the formulation of public health messages to instill confidence in new COVID-19 vaccines. Despite the pandemic being nearly over and many people worldwide having received COVID-19 vaccines, the findings provide important insight into potential issues regarding the introduction of new vaccines in the event of future pandemics.

Clinical impact of a community pharmacy-based health and wellness introductory pharmacy practice experience

OBJECTIVE

To assess the clinical impact of an intensive community pharmacy-based Health and Wellness Introductory Pharmacy Practice Experience (IPPE) completed by second-year (P2) student pharmacists.

DESIGN

The Health and Wellness IPPE was a 1-week rotation developed to provide P2 student pharmacists with opportunities to provide clinical services to patients within the community pharmacy setting. Student pharmacists administered immunizations, performed blood pressure screenings and blood glucose measurements, and provided education to patients under the guidance of licensed pharmacist preceptors.

SETTING AND PARTICIPANTS

Second-year student pharmacists completing a required Health and Wellness IPPE rotation in the community pharmacy setting.

OUTCOMES MEASURED

Student pharmacist interventions were assessed to determine the course's clinical impact, and preceptors were surveyed regarding the feasibility of student pharmacists performing clinical services at their training sites.

RESULTS

A total of 147 student pharmacists completed the IPPE at 89 community pharmacy training sites and administered 9392 injections, 90% of which were influenza vaccinations. Student pharmacists performed 3458 patient health assessments, including measuring patients' blood pressure and blood glucose and reviewing patient education materials. Most preceptors indicated that core activities were feasible during the experience.

CONCLUSION

This study found that implementing a concentrated IPPE focused on immunizations and health screenings allowed student pharmacists to enhance their clinical skills and fulfill a large public health need, improving patient outcomes. Future studies should explore utilizing student pharmacists in community pharmacy settings to expand clinical services offered beyond these 2 services, such as diabetes risk tests, influenza point-of-care testing, and smoking cessation counseling.

Varying Vaccination Rates Among Patients Seeking Care for Acute Respiratory Illness: A Systematic Review and Meta-analysis

Background

Complications following influenza infection are a major cause of morbidity and mortality, and the Centers for Disease Control Advisory Committee on Immunization Practices recommends universal annual vaccination. However, vaccination rates have remained significantly lower than the Department of Health and Human Services goal. The aim of this work was to assess the vaccination rate among patients who present to health care providers with influenza-like illness and identify groups with lower vaccination rates.

Methods

We performed a systematic search of the PubMed and EMBASE databases with a time frame of January 1, 2010, to March 1, 2019 and focused on the vaccination rate among patients seeking care for acute respiratory illness in the United States. A random effects meta-analysis was performed to estimate the pooled seasonal influenza vaccination rate, and we used a time trend analysis to identify differences in annual vaccination over time.

Results

The overall pooled influenza vaccination rate was 48.61% (whites: 50.87%; blacks: 36.05%; Hispanics: 41.45%). There was no significant difference among gender groups (men: 46.43%; women: 50.11%). Interestingly, the vaccination rate varied by age group and was significantly higher among adults aged >65 (78.04%) and significantly lower among children 9–17 years old (36.45%). Finally, we found a significant upward time trend in the overall influenza vaccination rate among whites (coef. = .0107; P = .027).

Conclusions

In conclusion, because of the significantly lower influenza vaccination rates in black and Hispanic communities, societal initiatives and community outreach programs should focus on these populations and on children and adolescents aged 9–17 years.

Elite athletes on regular training show more pronounced induction of vaccine-specific T-cells and antibodies after tetravalent influenza vaccination than controls

Compliance of elite athletes with vaccination recommendations is low mainly based on concerns about side-effects and perceived poor vaccine efficacy due to continued physical training. We therefore employed seasonal influenza vaccination to investigate the effect of regular physical training on vaccine-induced cellular and humoral immunity in elite athletes and controls. Lymphocyte subpopulations and vaccine-specific T-cells were quantified and functionally characterized from 45 athletes and 25 controls before, and 1, 2 and 26 weeks after vaccination. Moreover, influenza-specific antibodies and their neutralizing function were quantified. Both groups showed a significant increase in vaccine-reactive CD4 T-cell levels which peaked one week after vaccination (p < 0.0001). The increase was significantly more pronounced in athletes (4.1-fold) compared to controls (2.3-fold; p = 0.0007). The cytokine profile changed from multifunctional T-cells co-producing IFNγ, IL-2 and TNFα to cells with restricted cytokine expression. This change in functionality was associated with a significant increase in CTLA-4 expression (p < 0.0001), which again was more pronounced in athletes. Likewise, the increase in neutralizing antibodies was stronger in athletes (p = 0.004 for H1N1; p = 0.032 for H3N2). In conclusion, both groups mounted a strong vaccine-specific cellular and humoral immunity after standard vaccination. The more pronounced increase in specific T-cells and neutralizing antibodies indicates that high frequency and intensity of training enhance vaccine-responses in elite athletes.

Cost-effectiveness of increased influenza vaccination uptake against readmissions of major adverse cardiac events in the US

Background

Although influenza vaccination has been shown to reduce the incidence of major adverse cardiac events (MACE) among those with existing cardiovascular disease (CVD), in the 2015–16 season, coverage for persons with heart disease was only 48% in the US.

Methods

We built a Monte Carlo (probabilistic) spreadsheet-based decision tree in 2018 to estimate the cost-effectiveness of increased influenza vaccination to prevent MACE readmissions. We based our model on current US influenza vaccination coverage of the estimated 493,750 US acute coronary syndrome (ACS) patients from the healthcare payer perspective. We excluded outpatient costs and time lost from work and included only hospitalization and vaccination costs. We also estimated the incremental cost/MACE case averted and incremental cost/QALY gained (ICER) if 75% hospitalized ACS patients were vaccinated by discharge and estimated the impact of increasing vaccination coverage incrementally by 5% up to 95% in a sensitivity analysis, among hospitalized adults aged ≥ 65 years and 18–64 years, and varying vaccine effectiveness from 30–40%.

Result

At 75% vaccination coverage by discharge, vaccination was cost-saving from the healthcare payer perspective in adults ≥ 65 years and the ICER was $12,680/QALY (95% CI: 6,273–20,264) in adults 18–64 years and $2,400 (95% CI: -1,992–7,398) in all adults 18 + years. These resulted in ~ 500 (95% CI: 439–625) additional averted MACEs/year for all adult patients aged ≥18 years and added ~700 (95% CI: 578–825) QALYs. In the sensitivity analysis, vaccination becomes cost-saving in adults 18+years after about 80% vaccination rate. To achieve 75% vaccination rate in all adults aged ≥ 18 years will require an additional cost of $3 million. The effectiveness of the vaccine, cost of vaccination, and vaccination coverage rate had the most impact on the results.

Conclusion

Increasing vaccination rate among hospitalized ACS patients has a favorable cost-effectiveness profile and becomes cost-saving when at least 80% are vaccinated.

Cost-effectiveness of a domestic violence and abuse training and support programme in primary care in the real world: updated modelling based on an MRC phase IV observational pragmatic implementation study

OBJECTIVES

To evaluate the cost-effectiveness of the implementation of the Identification and Referral to Improve Safety (IRIS) programme using up-to-date real-world information on costs and effectiveness from routine clinical practice. A Markov model was constructed to estimate mean costs and quality-adjusted life-years (QALYs) of IRIS versus usual care per woman registered at a general practice from a societal and health service perspective with a 10-year time horizon.

DESIGN AND SETTING

Cost-utility analysis in UK general practices, including data from six sites which have been running IRIS for at least 2 years across England.

PARTICIPANTS

Based on the Markov model, which uses health states to represent possible outcomes of the intervention, we stipulated a hypothetical cohort of 10 000 women aged 16 years or older.

INTERVENTIONS

The IRIS trial was a randomised controlled trial that tested the effectiveness of a primary care training and support intervention to improve the response to women experiencing domestic violence and abuse, and found it to be cost-effective. As a result, the IRIS programme has been implemented across the UK, generating data on costs and effectiveness outside a trial context.

RESULTS

The IRIS programme saved £14 per woman aged 16 years or older registered in general practice (95% uncertainty interval -£151 to £37) and produced QALY gains of 0.001 per woman (95% uncertainty interval -0.005 to 0.006). The incremental net monetary benefit was positive both from a societal and National Health Service perspective (£42 and £22, respectively) and the IRIS programme was cost-effective in 61% of simulations using real-life data when the cost-effectiveness threshold was £20 000 per QALY gained as advised by National Institute for Health and Care Excellence.

CONCLUSION

The IRIS programme is likely to be cost-effective and cost-saving from a societal perspective in the UK and cost-effective from a health service perspective, although there is considerable uncertainty surrounding these results, reflected in the large uncertainty intervals.

Vaccines for preventing influenza in healthy adults

BACKGROUND

The consequences of influenza in adults are mainly time off work. Vaccination of pregnant women is recommended internationally. This is an update of a review published in 2014. 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 due to their lack of influence on the review conclusions.

OBJECTIVES

To assess the effects (efficacy, effectiveness, and harm) of vaccines against influenza in healthy adults, including pregnant women.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 12), MEDLINE (January 1966 to 31 December 2016), Embase (1990 to 31 December 2016), the WHO International Clinical Trials Registry Platform (ICTRP; 1 July 2017), and ClinicalTrials.gov (1 July 2017), as well as checking the bibliographies of retrieved articles.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing influenza vaccines with placebo or no intervention in naturally occurring influenza in healthy individuals aged 16 to 65 years. Previous versions of this review included observational comparative studies assessing serious and rare harms cohort and case-control studies. Due to the uncertain quality of observational (i.e. non-randomised) studies and their lack of influence on the review conclusions, we decided to update only randomised evidence. The searches for observational comparative studies are no longer updated.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. We rated certainty of evidence for key outcomes (influenza, influenza-like illness (ILI), hospitalisation, and adverse effects) using GRADE.

MAIN RESULTS

We included 52 clinical trials of over 80,000 people assessing the safety and effectiveness of influenza vaccines. We have presented findings from 25 studies comparing inactivated parenteral influenza vaccine against placebo or do-nothing control groups as the most relevant to decision-making. The studies were conducted over single influenza seasons in North America, South America, and Europe between 1969 and 2009. We did not consider studies at high risk of bias to influence the results of our outcomes except for hospitalisation.Inactivated influenza vaccines probably reduce influenza in healthy adults from 2.3% without vaccination to 0.9% (risk ratio (RR) 0.41, 95% confidence interval (CI) 0.36 to 0.47; 71,221 participants; moderate-certainty evidence), and they probably reduce ILI from 21.5% to 18.1% (RR 0.84, 95% CI 0.75 to 0.95; 25,795 participants; moderate-certainty evidence; 71 healthy adults need to be vaccinated to prevent one of them experiencing influenza, and 29 healthy adults need to be vaccinated to prevent one of them experiencing an ILI). The difference between the two number needed to vaccinate (NNV) values depends on the different incidence of ILI and confirmed influenza among the study populations. Vaccination may lead to a small reduction in the risk of hospitalisation in healthy adults, from 14.7% to 14.1%, but the CI is wide and does not rule out a large benefit (RR 0.96, 95% CI 0.85 to 1.08; 11,924 participants; low-certainty evidence). Vaccines may lead to little or no small reduction in days off work (-0.04 days, 95% CI -0.14 days to 0.06; low-certainty evidence). Inactivated vaccines cause an increase in fever from 1.5% to 2.3%.We identified one RCT and one controlled clinical trial assessing the effects of vaccination in pregnant women. The efficacy of inactivated vaccine containing pH1N1 against influenza was 50% (95% CI 14% to 71%) in mothers (NNV 55), and 49% (95% CI 12% to 70%) in infants up to 24 weeks (NNV 56). No data were available on efficacy against seasonal influenza during pregnancy. Evidence from observational studies showed effectiveness of influenza vaccines against ILI in pregnant women to be 24% (95% CI 11% to 36%, NNV 94), and against influenza in newborns from vaccinated women to be 41% (95% CI 6% to 63%, NNV 27).Live aerosol vaccines have an overall effectiveness corresponding to an NNV of 46. The performance of one- or two-dose whole-virion 1968 to 1969 pandemic vaccines was higher (NNV 16) against ILI and (NNV 35) against influenza. There was limited impact on hospitalisations in the 1968 to 1969 pandemic (NNV 94). The administration of both seasonal and 2009 pandemic vaccines during pregnancy had no significant effect on abortion or neonatal death, but this was based on observational data sets.

AUTHORS' CONCLUSIONS

Healthy adults who receive inactivated parenteral influenza vaccine rather than no vaccine probably experience less influenza, from just over 2% to just under 1% (moderate-certainty evidence). They also probably experience less ILI following vaccination, but the degree of benefit when expressed in absolute terms varied across different settings. Variation in protection against ILI may be due in part to inconsistent symptom classification. Certainty of evidence for the small reductions in hospitalisations and time off work is low. Protection against influenza and ILI in mothers and newborns was smaller than the effects seen in other populations considered in this review.Vaccines increase the risk of a number of adverse events, including a small increase in fever, but rates of nausea and vomiting are uncertain. The protective effect of vaccination in pregnant women and newborns is also very modest. We did not find any evidence of an association between influenza vaccination and serious adverse events in the comparative studies considered in this review. Fifteen included RCTs were industry funded (29%).

Ultra scale-down approaches to study the centrifugal harvest for viral vaccine production

Large scale continuous cell-line cultures promise greater reproducibility and efficacy for the production of influenza vaccines, and adenovirus for gene therapy. This paper seeks to use an existing validated ultra scale-down tool, which is designed to mimic the commercial scale process environment using only milliliters of material, to provide some initial insight into the performance of the harvest step for these processes. The performance of industrial scale centrifugation and subsequent downstream process units is significantly affected by shear. The properties of these cells, in particular their shear sensitivity, may be changed considerably by production of a viral product, but literature on this is limited to date. In addition, the scale-down tool used here has not previously been applied to the clarification of virus production processes. The results indicate that virus infected cells do not actually show any increase in sensitivity to shear, and may indeed become less shear sensitive, in a similar manner to that previously observed in old or dead cell cultures. Clarification may be most significantly dependent on the virus release mechanism, with the budding influenza virus producing a much greater decrease in clarification than the lytic, non-enveloped adenovirus. A good match was also demonstrated to the industrial scale performance in terms of clarification, protein release, and impurity profile.

A Y161F Hemagglutinin Substitution Increases Thermostability and Improves Yields of 2009 H1N1 Influenza A Virus in Cells

Vaccination is the primary strategy for influenza prevention and control. However, egg-based vaccines, the predominant production platform, have several disadvantages, including the emergence of viral antigenic variants that can be induced during egg passage. These limitations have prompted the development of cell-based vaccines, which themselves are not without issue. Most importantly, vaccine seed viruses often do not grow efficiently in mammalian cell lines. Here we aimed to identify novel high-yield signatures for influenza viruses in continuous Madin-Darby canine kidney (MDCK) and Vero cells. Using influenza A(H1N1)pdm09 virus as the testing platform and an integrating error-prone PCR-based mutagenesis strategy, we identified a Y161F mutation in hemagglutinin (HA) that not only enhanced the infectivity of the resultant virus by more than 300-fold but also increased its thermostability without changing its original antigenic properties. The vaccine produced from the Y161F mutant fully protected mice against lethal challenge with wild-type A(H1N1)pdm09. Compared with A(H1N1)pdm09, the Y161F mutant had significantly higher avidity for avian-like and human-like receptor analogs. Of note, the introduction of the Y161F mutation into HA of seasonal H3N2 influenza A virus (IAV) and canine H3N8 IAV also increased yields and thermostability in MDCK cells and chicken embryotic eggs. Thus, residue F161 plays an important role in determining viral growth and thermostability, which could be harnessed to optimize IAV vaccine seed viruses.IMPORTANCE Although a promising complement to current egg-based influenza vaccines, cell-based vaccines have one large challenge: high-yield vaccine seeds for production. In this study, we identified a molecular signature, Y161F, in hemagglutinin (HA) that resulted in increased virus growth in Madin-Darby canine kidney and Vero cells, two cell lines commonly used for influenza vaccine manufacturing. This Y161F mutation not only increased HA thermostability but also enhanced its binding affinity for α2,6- and α2,3-linked Neu5Ac. These results suggest that a vaccine strain bearing the Y161F mutation in HA could potentially increase vaccine yields in mammalian cell culture systems.

A growing world of small things: a brief review on the nanostructured vaccines

Vaccines are the most cost-effective intervention in the management of infectious disease. Much of what we perceive as quality of life is related to a good health status and disease absence, for which vaccines are substantially responsible. Nonetheless, there are many infectious diseases for which no vaccine solution is available. That could be due to limitations of the classic approaches to vaccine development, including inactivated, subunit and attenuated vaccines. Nanostructured immunogens belong to a class of nonclassic vaccines in which nanostructures are loaded with antigen-related molecules. Here, we briefly review important features of the nanostructured vaccines – mainly those based in carbon nanotubes and gold nanorods – and discuss their use to prevent infectious diseases, especially those caused by viruses.

The Clinical Impact and Cost Effectiveness of Quadrivalent Versus Trivalent Influenza Vaccination in Finland

BACKGROUND

Trivalent influenza vaccines encompass one influenza B lineage; however, predictions have been unreliable on which of two antigenically distinct circulating lineages will dominate. Quadrivalent seasonal influenza vaccines contain strains from both lineages. This analysis assesses the cost effectiveness of switching from trivalent inactivated influenza vaccination (TIV) in Finland to quadrivalent vaccination, using inactivated (QIV) or live-attenuated (Q-LAIV) vaccines.

METHODS

A transmission model simulated the dynamics of influenza infection while accounting for indirect (herd) protection. Prior distributions for key transmission parameters were repeatedly sampled and simulations that fitted the available information on influenza in Finland were recorded. The resulting posterior parameter distributions were used in a probabilistic sensitivity analysis in which economic parameters were sampled, simultaneously encompassing uncertainty in the transmission and economic parameters. The cost effectiveness of a range of trivalent and quadrivalent vaccine policies over a 20-year time horizon was assessed from both a societal and payer perspective in 2014 Euros.

RESULTS

The simulated temporal incidence pattern of symptomatic infections corresponded well with case surveillance data. A switch from the current TIV to Q-LAIV in children (2 to <18 years) and to QIV in other ages was estimated to annually avert approximately 76,100 symptomatic infections (95 % range 36,700-146,700), 11,500 primary care consultations (6100-20,000), 540 hospitalisations (240-1180), and 72 deaths (32-160), and was cost-saving relative to TIV (€374 million averted [€161-€752], in 2014 Euros, discounted at 3 %). This scenario had the highest probability of being the most cost-effective scenario considered.

CONCLUSIONS

This analysis demonstrates that quadrivalent vaccination is expected to be highly cost effective, reducing the burden of influenza-related disease.

Economic evaluation of pediatric influenza immunization program compared with other pediatric immunization programs: A systematic review

This study compared the economic value of pediatric immunisation programmes for influenza to those for rotavirus (RV), meningococcal disease (MD), pneumococcal disease (PD), human papillomavirus (HPV), hepatitis B (Hep B), and varicella reported in recent (2000 onwards) cost-effectiveness (CE) studies identified in a systematic review of PubMed, health technology, and vaccination databases. The systematic review yielded 51 economic evaluation studies of pediatric immunisation - 10 (20%) for influenza and 41 (80%) for the other selected diseases. The quality of the eligible articles was assessed using Drummond's checklist. Although inherent challenges and limitations exist when comparing economic evaluations of immunisation programmes, an overall comparison of the included studies demonstrated cost-effectiveness/cost saving for influenza from a European-Union-Five (EU5) and United States (US) perspective; point estimates for cost/quality-adjusted life-years (QALY) from dominance (cost-saving with more effect) to ≤45,444 were reported. The economic value of influenza programmes was comparable to the other vaccines of interest, with cost/QALY in general considerably lower than RV, Hep B, MD and PD. Independent of the perspective and type of analysis, the economic impact of a pediatric influenza immunisation program was influenced by vaccine efficacy, immunisation coverage, costs, and most significantly by herd immunity. This review suggests that pediatric influenza immunisation may offer a cost effective strategy when compared with HPV and varicella and possibly more value compared with other childhood vaccines (RV, Hep B, MD and PD).

Connecting within and between-hosts dynamics in the influenza infection-staged epidemiological models with behavior change

Influenza viruses are a major public health problem worldwide. Although influenza has been extensively researched, there are still many aspects that are not fully understood such as the effects of within and between-hosts dynamics and their impact on behavior change. Here, we develop mathematical models with multiple infection stages and estimate parameters based on within-host data to investigate the impact of behavior change on influenza dynamics. We divide the infected population into three and four groups based on the age of the infection, which corresponds to viral load shedding. We consider within-host data on viral shedding to estimate the length and force of infection of the different infectivity stages. Our results show that behavior changes, due to exogenous events (e.g., media coverage) and disease symptoms, are effective in delaying and lowering an epidemic peak. We show that the dynamics of viral shedding and symptoms, during the infection, are key features when considering epidemic prevention strategies. This study improves our understanding of the spread of influenza virus infection in the population and provides information about the impact of emergent behavior and its connection to the within and between-hosts dynamics.

Vaccines for preventing influenza in healthy adults

BACKGROUND

Different types of influenza vaccines are currently produced worldwide. Vaccination of pregnant women is recommended internationally, while healthy adults are targeted in North America.

OBJECTIVES

To identify, retrieve and assess all studies evaluating the effects (efficacy, effectiveness and harm) of vaccines against influenza in healthy adults, including pregnant women.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 2), MEDLINE (January 1966 to May 2013) and EMBASE (1990 to May 2013).

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing influenza vaccines with placebo or no intervention in naturally occurring influenza in healthy individuals aged 16 to 65 years. We also included comparative studies assessing serious and rare harms.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data.

MAIN RESULTS

We included 90 reports containing 116 data sets; among these 69 were clinical trials of over 70,000 people, 27 were comparative cohort studies (about eight million people) and 20 were case-control studies (nearly 25,000 people). We retrieved 23 reports of the effectiveness and safety of vaccine administration in pregnant women (about 1.6 million mother-child couples).The overall effectiveness of parenteral inactivated vaccine against influenza-like illness (ILI) is limited, corresponding to a number needed to vaccinate (NNV) of 40 (95% confidence interval (CI) 26 to 128). The overall efficacy of inactivated vaccines in preventing confirmed influenza has a NNV of 71 (95% CI 64 to 80). The difference between these two values depends on the different incidence of ILI and confirmed influenza among the study populations: 15.6% of unvaccinated participants versus 9.9% of vaccinated participants developed ILI symptoms, whilst only 2.4% and 1.1%, respectively, developed laboratory-confirmed influenza.No RCTs assessing vaccination in pregnant women were found. The only evidence available comes from observational studies with modest methodological quality. On this basis, vaccination shows very limited effects: NNV 92 (95% CI 63 to 201) against ILI in pregnant women and NNV 27 (95% CI 18 to 185) against laboratory-confirmed influenza in newborns from vaccinated women.Live aerosol vaccines have an overall effectiveness corresponding to a NNV 46 (95% CI 29 to 115).The performance of one-dose or two-dose whole virion pandemic vaccines was higher, showing a NNV of 16 (95% CI 14 to 20) against ILI and a NNV of 35 (95% CI 33 to 47) against influenza, while a limited impact on hospitalisation was found (NNV 94, 95% CI 70 to 1022).Vaccination had a modest effect on time off work and had no effect on hospital admissions or complication rates. Inactivated vaccines caused local harms. No evidence of association with serious adverse events was found, but the harms evidence base was limited.The overall risk of bias in the included trials is unclear because it was not possible to assess the real impact of bias.

AUTHORS' CONCLUSIONS

Influenza vaccines have a very modest effect in reducing influenza symptoms and working days lost in the general population, including pregnant women. No evidence of association between influenza vaccination and serious adverse events was found in the comparative studies considered in the review. This review includes 90 studies, 24 of which (26.7%) were funded totally or partially by industry. Out of the 48 RCTs, 17 were industry-funded (35.4%).

Impact of influenza on health-related quality of life among confirmed (H1N1)2009 patients

BACKGROUND

We aimed to assess the changes in health-related quality of life (HRQL) in patients with confirmed diagnosis of influenza (H1N1)2009, and to estimate the individual and societal loss of quality-adjusted life years (QALYs) caused by the pandemic.

METHODS AND RESULTS

Longitudinal study of patients recruited at major hospitals and primary care centers in Spain. Patients reported their HRQL (EQ-5D) during their influenza episode and seven days prior to it. A subsample was monitored to evaluate HRQL after recovery. HRQL loss was estimated as the difference between EQ-5D prior to the influenza episode and during it. Individual QALY loss (disutility multiplied by the duration of the influenza episode in days) for confirmed cases was calculated and used to estimate the societal loss in Spain (with the official estimations). A total of 432 inpatients and 563 outpatients were included, of whom 145 and 184, respectively, were followed up. Baseline mean HRQL loss was 0.58 (95% CI, 0.53-0.63) for inpatients and 0.43 (95% CI, 0.40-0.46) for outpatients. The majority of the 145 inpatients and 184 outpatients who were followed up regained initial HRQL levels, presenting a mean difference of 0.01 between the EQ-5D score prior to and after the influenza episode. Individual QALY losses for inpatients (0.031, 95% CI, 0.025-0.037) were higher than for outpatients (0.009, 95% CI, 0.007-0.011), while societal QALY losses were reversed: 94 years for inpatients and 6,778 years for outpatients. For fatal cases (an official number of 318), we estimated a QALY loss of 11,981.

CONCLUSIONS

The influenza (H1N1)2009 pandemic had a significant but temporary impact on the HRQL of the majority of confirmed in- and outpatients. The societal impact of the influenza pandemic in Spain was estimated to be higher than other acute conditions. These results provide useful data for future cost-utility analyses.

Recommendations for the prevention and treatment of influenza using antiviral drugs based on cost-effectiveness

Influenza is an acute respiratory disease that causes epidemics and pandemics in the human population of temperate regions. Influenza epidemics occur every year during the winter months, affecting approximately 10% of the population. The primary strategy for reducing the effect of influenza in the community is to vaccinate persons who are at risk or caring for high-risk individuals each year before seasonal increases in influenza virus circulation occur. Antiviral drugs can be used for the treatment of influenza and the prevention of seasonal and post-exposure influenza. Four antiviral drugs are available for the prevention and treatment of influenza infections: oseltamivir, zanamivir, rimantadine and amantadine. Antiviral drugs can be used for the treatment of influenza and for post-exposure and seasonal influenza prevention. The cost-effectiveness of antiviral therapies ranged from cost savings to more than US$130,000 per quality-adjusted life-year (QALY) for influenza treatment, from GB pound9000 to more than pound1 million per QALY for seasonal prevention and from cost savings to pound100,000 per QALY for post-exposure prevention. Based on the cost-effectiveness threshold of pound30,000 or $40,000 per QALY, antiviral therapies can be recommended for influenza treatment and post-exposure prevention in healthy and high-risk individuals and for seasonal prevention in high-risk individuals. Zanamivir, oseltamivir and amantadine have favorable cost-effectiveness ratios for these interventions, but amantadine should only be used in countries with a low prevalence of resistant virus. The stockpile of antiviral drugs should be maintained in developed countries because they are cost effective for the prevention and treatment of a possible influenza pandemic.

Issues in the economic evaluation of influenza vaccination by injection of healthy working adults in the US: a review and decision analysis of ten published studies

The objective was to review recent economic evaluations of influenza vaccination by injection in the US, assess their evidence, and conclude on their collective findings. The literature was searched for economic evaluations of influenza vaccination injection in healthy working adults in the US published since 1995. Ten evaluations described in nine papers were identified. These were synopsized and their results evaluated, the basic structure of all evaluations was ascertained, and sensitivity of outcomes to changes in parameter values were explored using a decision model. Areas to improve economic evaluations were noted. Eight of nine evaluations with credible economic outcomes were favourable to vaccination, representing a statistically significant result compared with a proportion of 50% that would be expected if vaccination and no vaccination were economically equivalent. Evaluations shared a basic structure, but differed considerably with respect to cost components, assumptions, methods, and parameter estimates. Sensitivity analysis indicated that changes in parameter values within the feasible range, individually or simultaneously, could reverse economic outcomes. Given stated misgivings, the methods of estimating influenza reduction ascribed to vaccination must be researched to confirm that they produce accurate and reliable estimates. Research is also needed to improve estimates of the costs per case of influenza illness and the costs of vaccination. Based on their assumptions, the reviewed papers collectively appear to support the economic benefits of influenza vaccination of healthy adults. Yet the underlying assumptions, methods and parameter estimates themselves warrant further research to confirm they are accurate, reliable and appropriate to economic evaluation purposes.

Effect of influenza treatment with oseltamivir on health outcome and costs in otherwise healthy children

OBJECTIVE

To evaluate the effect of treating children with influenza with oseltamivir on health outcomes and costs to healthcare payers.

PATIENTS AND DESIGN

Health outcome data from the oseltamivir paediatric clinical development programme plus data from the literature were used in an economic model developed to predict morbidity and mortality due to influenza and its specified complications. Published data on the cost of care in the UK were used to compare oseltamivir with usual care in children aged 1-12 and 1-5 years by estimating cost-effectiveness and cost-utility ratios.

RESULTS

Oseltamivir reduced median time to return to normal health and activity by almost 2 days (40% reduction, 67.1 vs 111.7 hours; p < 0.0001) versus placebo. In children aged 1-5 years, a 48% reduction (63.5 vs 121.3 hours; p = 0.0003) was observed. Oseltamivir-treated children who developed otitis media returned to normal health and activity 30% faster (99.6 vs 141.5 hours; p = 0.0517) than the placebo group. In the economic model, oseltamivir in the base-case analysis (assuming 60% diagnostic accuracy, full compliance, and 100% receive and start treatment within 48 hours, standard discounting according to the UK National Institute of Clinical Excellence guidelines) resulted in favourable cost-utility ratios in children aged both 1-12 and 1-5 years, with incremental cost-utility rates of £11 173/quality-adjusted life year (QALY) and oseltamivir being dominant compared with usual care, respectively (year of costing, 2002). Even in conservative scenarios, most cost-utility ratios remained <£30 000/QALY.

CONCLUSIONS

Oseltamivir is an effective treatment for children with influenza, allowing faster return to normal health and activity compared with usual care. From the healthcare payer perspective, oseltamivir is a potentially cost-effective strategy for otherwise healthy children.

Immunizing Against Prejudice

Contemporary interpersonal biases are partially derived from psychological mechanisms that evolved to protect people against the threat of contagious disease. This behavioral immune system effectively promotes disease avoidance but also results in an overgeneralized prejudice toward people who are not legitimate carriers of disease. In three studies, we tested whether experiences with two modern forms of disease protection (vaccination and hand washing) attenuate the relationship between concerns about disease and prejudice against out-groups. Study 1 demonstrated that when threatened with disease, vaccinated participants exhibited less prejudice toward immigrants than unvaccinated participants did. In Study 2, we found that framing vaccination messages in terms of immunity eliminated the relationship between chronic germ aversion and prejudice. In Study 3, we directly manipulated participants’ protection from disease by having some participants wash their hands and found that this intervention significantly influenced participants’ perceptions of out-group members. Our research suggests that public-health interventions can benefit society in areas beyond immediate health-related domains by informing novel, modern remedies for prejudice.

Vaccines for preventing influenza in healthy adults

BACKGROUND

Different types of influenza vaccines are currently produced worldwide. Healthy adults are presently targeted mainly in North America.

OBJECTIVES

Identify, retrieve and assess all studies evaluating the effects of vaccines against influenza in healthy adults.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2010, issue 2), MEDLINE (January 1966 to June 2010) and EMBASE (1990 to June 2010).

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing influenza vaccines with placebo or no intervention in naturally-occurring influenza in healthy individuals aged 16 to 65 years. We also included comparative studies assessing serious and rare harms.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data.

MAIN RESULTS

We included 50 reports. Forty (59 sub-studies) were clinical trials of over 70,000 people. Eight were comparative non-RCTs and assessed serious harms. Two were reports of harms which could not be introduced in the data analysis. In the relatively uncommon circumstance of vaccine matching the viral circulating strain and high circulation, 4% of unvaccinated people versus 1% of vaccinated people developed influenza symptoms (risk difference (RD) 3%, 95% confidence interval (CI) 2% to 5%). The corresponding figures for poor vaccine matching were 2% and 1% (RD 1, 95% CI 0% to 3%). These differences were not likely to be due to chance. Vaccination had a modest effect on time off work and had no effect on hospital admissions or complication rates. Inactivated vaccines caused local harms and an estimated 1.6 additional cases of Guillain-Barré Syndrome per million vaccinations. The harms evidence base is limited.

AUTHORS' CONCLUSIONS

Influenza vaccines have a modest effect in reducing influenza symptoms and working days lost. There is no evidence that they affect complications, such as pneumonia, or transmission.WARNING: This review includes 15 out of 36 trials funded by industry (four had no funding declaration). An earlier systematic review of 274 influenza vaccine studies published up to 2007 found industry funded studies were published in more prestigious journals and cited more than other studies independently from methodological quality and size. Studies funded from public sources were significantly less likely to report conclusions favorable to the vaccines. The review showed that reliable evidence on influenza vaccines is thin but there is evidence of widespread manipulation of conclusions and spurious notoriety of the studies. The content and conclusions of this review should be interpreted in light of this finding.

Cost-effective approaches to influenza prevention and treatment

Influenza, the seventh leading cause of death in the USA, accounts for 35,000 deaths and over 200,000 hospitalizations annually in that country alone. Recent advances in influenza vaccines, diagnosis and treatment have created numerous options for practicing clinicians, as well as economic opportunities for the makers of vaccines, rapid diagnostic tests and antiviral drugs. Since influenza-like illness affects up to half of the population each year, selective use of expensive tests and treatments is essential to the practice of cost-effective medicine. Over the past 5 years, dozens of economic evaluations of influenza vaccination, rapid testing and antiviral therapy have been published, many of which are free of commercial bias. The existing literature, drawing practical lessons for clinical practice is reviewed, and new developments on the horizon are explored including vaccines, surveillance methods, antiviral agents and pandemic preparedness.

Economic evaluations of neuraminidase inhibitors to control influenza

Up to 10% of individuals present influenza-like illness each year. Neuraminidase inhibitors significantly reduce the median duration of influenza symptoms by 1.38 days and median time to return to normal activities by 0.9 days in adults. This review presents the economic evaluations of neuraminidase inhibitors in adults. The choice of key parameter estimates in cost-effectiveness and cost-benefit analysis is sensitive to the perspective of analysis: healthcare payer or societal, including productivity gains. This review discusses, among other key parameters, the proportion of influenza-like illness due to the influenza virus (targeted by neuraminidase inhibitors and influenza vaccine), and the measure of health benefits by either quality-adjusted life years gained or willingness-to-pay for a day of symptoms averted. Overall, neuraminidase inhibitors are worth their costs and do not challenge annual influenza vaccination but should be seen as a complementary option to reduce the burden of influenza.

Antiviral medications for pregnant women for pandemic and seasonal influenza: an economic computer model

OBJECTIVE

To estimate the economic value of administering antiviral medications to pregnant women who have come in contact with an infectious individual with influenza.

METHODS

A computer-simulation model was developed to predict the potential economic effect of antiviral use for postexposure prophylaxis among pregnant women in both seasonal influenza and pandemic influenza scenarios. The model allowed us to examine the effects of varying influenza exposure risk, antiviral efficacy, antiviral cost, and the probability of different influenza outcomes such as hospitalization, preterm delivery, and mortality.

RESULTS

For a variety of pandemic influenza scenarios (attack rate 20% or more, probability of preterm birth for women with influenza 12% or more, mortality for a preterm neonate 2% or more, and probability of influenza-attributable hospitalization 4.8% or more), the postexposure prophylactic use of antiviral medications was strongly cost-effective, with incremental cost-effectiveness ratio values below $50,000 per quality-adjusted life-year. Antiviral prophylaxis became an economically dominant strategy (that is, less costly and more effective) when the influenza attack rate is 20% or more and preterm birth rate is 36% or more, and when attack rate is 30% or more and preterm birth rate is 24% or more. Antiviral prophylaxis was not cost-effective under seasonal influenza conditions.

CONCLUSION

These findings support the use of antiviral medications for postexposure prophylaxis among pregnant women in a pandemic influenza scenario but not in a seasonal influenza setting.

Targeted vs. systematic early antiviral treatment against A(H1N1)v influenza with neuraminidase inhibitors in patients with influenza-like symptoms: clinical and economic impact

Capitalizing on available data, we used a decision model to estimate the clinical and economic outcomes associated with early initiation of treatment with neuraminidase inhibitors in all patients with influenza-like illnesses ( ILI ) (systematic strategy) vs. only those at high risk of complications (targeted strategy). Systematic treatment of ILI during an A(H1N1)v influenza epidemic wave is both effective and cost-effective. Patients who present to care with ILI during an A(H1N1)v influenza epidemic wave should initiate treatment with neuraminidase inhibitors, regardless of risk status. Administering neuraminidase inhibitors between epidemic waves, when the probability of influenza is low, is less effective and cost-effective.

Racial and ethnic disparities in pneumonia treatment and mortality

BACKGROUND

The extent to which racial/ethnic disparities in pneumonia care occur within or between hospitals is unclear.

OBJECTIVE

Examine within and between-hospital racial/ethnic disparities in quality indicators and mortality for patients hospitalized for pneumonia.

RESEARCH DESIGN

Retrospective cohort study.

SUBJECTS

A total of 1,183,753 non-Hispanic white, African American, and Hispanic adults hospitalized for pneumonia between January 2005 and June 2006.

MEASURES

Eight pneumonia care quality indicators and in-hospital mortality.

RESULTS

Performance rates for the 8 quality indicators ranged from 99.4% (oxygenation assessment within 24 hours) to 60.2% (influenza vaccination). Overall hospital mortality was 4.1%. African American and Hispanic patients were less likely to receive pneumococcal and influenza vaccinations, smoking cessation counseling, and first dose of antibiotic within 4 hours than white patients at the same hospital (ORs = 0.65-0.95). Patients at hospitals with the racial composition of those attended by average African Americans and Hispanics were less likely to receive all indicators except blood culture within 24 hours than patients at hospitals with the racial composition of those attended by average whites. Hospital mortality was higher for African Americans (OR = 1.05; 95% CI = 1.02, 1.09) and lower for Hispanics (OR = 0.85; 95% CI = 0.81, 0.89) than for whites within the same hospital. Mortality for patients at hospitals with the racial composition of those attended by average African Americans (OR = 1.21; 95% CI = 1.18, 1.25) or Hispanics (OR = 1.18; 95% CI = 1.14, 1.23) was higher than for patients at hospitals with the racial composition of those attended by average whites.

CONCLUSIONS

Racial/ethnic disparities in pneumonia treatment and mortality are larger and more consistent between hospitals than within hospitals.

Respiratory syncytial virus: an important cause of acute respiratory illness among young adults undergoing military training

Background  Military recruits receiving training are vulnerable to acute respiratory disease and a significant proportion of illness is caused by unidentified pathogens. While some countries use surveillance programmes to monitor such illness, few data exist for recruits of the British Armed Forces.

Objectives  Through active surveillance of approximately 1000 Royal Navy trainees during 2001, we sought to describe and determine the aetiology of acute respiratory illness.

Methods  Standard viral culture was used together with serology and a novel highly sensitive real‐time PCR and molecular beacon probe assay for respiratory syncytial virus (RSV) detection.

Results  Among 54 Royal Navy recruits with respiratory symptoms adenovirus was identified in 35%, influenza viruses in 19% and RSV in 14%. All recruits were absent from training for almost a week, most of whom were confined to the sickbay.

Conclusions  This study is the first to document adenovirus and RSV as important causes of acute respiratory illness among Royal Navy trainees. The study findings demonstrate the clinical significance and challenges of diagnosing RSV infection in young adults.

[Use of European Quality of Life-5 Dimensions (EQ-5D) questionnary to value the health related quality of life variation because of influenza]

OBJECTIVE

To describe self-perceived health status and health-related quality of life (HRQoL) in healthy individuals of working age, to measure changes due to influenza infection, and to evaluate the effect of influenza infection on HRQoL in monetary terms.

METHOD

We performed a descriptive observational study through questionnaires administered to 50 patients of working age infected with the influenza virus during the epidemiologic year 2004-2005 and living in private homes of the city of Logroño (Spain). The patients completed the questionnaires twice: with and without influenza. The dimensions and HRQoL indicators of the European Quality of Life-5 Dimensions (EQ-5D) questionnaire were evaluated. HRQoL utility indices were used to calculate lost quality-adjusted life years (QALYs).

RESULTS

On average, the reduction in the HRQoL utility index caused by influenza infection was between 0.37 and 0.65, on a scale from 0 (death) to 1 (perfect health). An influenza epidemic in 100,000 individuals could imply a loss of 137 QALYs, which in monetary terms could represent 2,722,609euro.

CONCLUSIONS

The EQ-5D dimension most negatively affected by influenza was <<daily activities>> while the least affected dimension was <<anxiety/depression>>. Influenza causes substantial losses in HRQoL among the population of working age. The results of the sensitivity analysis of the monetary effects of influenza infection yielded intervals showing a range of more than 5 times the mean value.

Cost effectiveness of oseltamivir treatment of influenza: a critique of published methods and outcomes

OBJECTIVE

The objective of this review was to determine, from a systematic assessment of published data, the cost effectiveness of the neuraminidase inhibitor antiviral medication oseltamivir in comparison with usual care (i.e. over-the-counter medication such as analgesics and antipyretics for symptomatic relief) for the treatment of influenza. How the findings of each of the studies considered related to the methods used for each analysis and the assumptions made were specifically reviewed.

RESULTS

The online search found 80 individual articles, 66 of which did not meet the pre-defined screening criteria. The 14 studies remaining reported cost, cost-effectiveness and cost-utility analyses for oseltamivir treatment in various groups: healthy adults and adolescents, children, elderly, and individuals at increased risk.

CONCLUSION

Despite the range of values assumed for key probabilities such as the diagnostic certainty of influenza among people presenting with influenza-like illness, and how much work time is lost due to illness in healthy adults, base-case analyses consistently showed oseltamivir treatment to be cost effective or even cost saving for the four population groups studied, a conclusion that is in-line with previous reviews on this topic. However, clarity was frequently lacking in the published data in terms of various model assumptions and results, particularly with regards to the exact distributions of the constituting elements of savings and of quality-adjusted life years gained.

Dynamic modelling of infectious diseases: an application to the economic evaluation of influenza vaccination

OBJECTIVE

To evaluate the economic efficiency of influenza vaccination using both dynamic and static modelling approaches.

SETTING

The Spanish National Health System.

DESIGN AND METHODS

We modelled the progress of an influenza epidemic in Spain according to the epidemiological pattern of susceptible-->infective-->resistant, employing a non-linear system of ordinary differential equations that enables the measurement of epidemiological effects of an anti-influenza vaccination. We used a decision tree to represent the repercussion on healthcare resources use and on financial resources. The same analyses were conducted using a static approach, and the results were compared. Healthcare costs were valued in euro, year 2005 values.

RESULTS

For the base case, the impact of the healthcare intervention (vaccination) was not efficient from the perspective of the healthcare payer when using a static approach (return rate 0.28 per euro invested in vaccination). Nevertheless, it was efficient when employing a dynamic approach (return rate 1.22 per euro). Furthermore, a considerable freeing of healthcare resources would have been produced over the entire influenza season.

CONCLUSIONS

The indirect effect of vaccination on the non-vaccinated individuals (the 'herd immunity effect') can be greater than the direct effect on individuals vaccinated. This implies that the herd immunity effect needs to be taken into consideration in the economic evaluations of prophylactic measures employed against infectious diseases.

Vaccines for preventing influenza in healthy adults

BACKGROUND

Different types of influenza vaccines are currently produced world-wide. Healthy adults are at present targeted only in North America. Despite the publication of a large number of clinical trials, there is still substantial uncertainty about the clinical effectiveness of influenza vaccines and this has a negative impact on their acceptance and uptake.

OBJECTIVES

To identify, retrieve and assess all studies evaluating the effects (efficacy, effectiveness and harms) of vaccines against influenza in healthy adults.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 4, 2005) which contains the Cochrane Acute Respiratory Infections Group trials register; MEDLINE (January 1966 to January 2006); and EMBASE (1990 to January 2006). We wrote to vaccine manufacturers and first or corresponding authors of studies in the review.

SELECTION CRITERIA

Any randomised or quasi-randomised studies comparing influenza vaccines in humans with placebo, no intervention. Live, attenuated, or killed vaccines or fractions of them administered by any route, irrespective of antigenic configuration were assessed. Only studies assessing protection from exposure to naturally occurring influenza in healthy individuals aged 16 to 65 years were considered. Comparative non-randomised studies were included if they assessed evidence of the possible association between influenza vaccines and serious harms.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data.

MAIN RESULTS

Forty-eight reports were included: 38 (57 sub-studies) were clinical trials providing data about effectiveness, efficacy and harms of influenza vaccines and involved 66,248 people; 8 were comparative non-randomised studies and tested the association of the vaccines with serious harms; 2 were reports of harms which could not be introduced in the data analysis. Inactivated parenteral vaccines were 30% effective (95% CI 17% to 41%) against influenza-like illness, and 80% (95% CI 56% to 91%) efficacious against influenza when the vaccine matched the circulating strain and circulation was high, but decreased to 50% (95% CI 27% to 65%) when it did not. Excluding the studies of the 1968 to 1969 pandemic, effectiveness was 15% (95% CI 9% to 22%) and efficacy was 73% (95% CI 53% to 84%). Vaccination had a modest effect on time off work, but there was insufficient evidence to draw conclusions on hospital admissions or complication rates. Inactivated vaccines caused local tenderness and soreness and erythema. Spray vaccines had more modest performance. Monovalent whole-virion vaccines matching circulating viruses had high efficacy (VE 93%, 95% CI 69% to 98%) and effectiveness (VE 66%, 95% CI 51% to 77%) against the 1968 to 1969 pandemic.

AUTHORS' CONCLUSIONS

Influenza vaccines are effective in reducing cases of influenza, especially when the content predicts accurately circulating types and circulation is high. However, they are less effective in reducing cases of influenza-like illness and have a modest impact on working days lost. There is insufficient evidence to assess their impact on complications. Whole-virion monovalent vaccines may perform best in a pandemic.

Cost-effectiveness of universal influenza vaccination in a pregnant population

OBJECTIVE

The purpose of this study was to estimate whether universal influenza vaccination of pregnant women was cost-effective in the management of influenza-like illness during influenza season.

METHODS

A decision analysis model was developed to investigate the cost-effectiveness of providing inactivated trivalent influenza vaccine to all pregnant women. This scenario was compared with providing supportive care only on a case-by-case basis to the unvaccinated pregnant population.

RESULTS

Vaccination of 100% of pregnant women would save approximately 50 dollars per woman, resulting in a net gain of approximately 45 quality-adjusted hours relative to providing supportive care only.

CONCLUSION

Universal vaccination with inactivated trivalent influenza vaccine is cost-saving relative to providing supportive care alone in the pregnant population.

LEVEL OF EVIDENCE

III.

Economics of neuraminidase inhibitor stock piling for pandemic influenza, Singapore

We compared strategies for stock piling neuraminidase inhibitors to treat and prevent influenza in Singapore. Cost-benefit and cost-effectiveness analyses, with Monte Carlo simulations, were used to determine economic outcomes. A pandemic in a population of 4.2 million would result in an estimated 525-1,775 deaths, 10,700-38,600 hospitalization days, and economic costs of 0.7 dollars to 2.2 billion Singapore dollars. The treatment-only strategy had optimal economic benefits: stock piles of antiviral agents for 40% of the population would save an estimated 418 lives and 414 million dollars, at a cost of 52.6 million dollars per shelf-life cycle of the stock pile. Prophylaxis was economically beneficial in high-risk subpopulations, which account for 78% of deaths, and in pandemics in which the death rate was >0.6%. Prophylaxis for pandemics with a 5% case-fatality rate would save 50,000 lives and 81 billion dollars. These models can help policymakers weigh the options for pandemic planning.

Incidence of influenza in Ontario following the Universal Influenza Immunization Campaign

The purpose of this study was to determine whether the incidence of influenza in Ontario, Canada has decreased following the introduction of the Universal Influenza Immunization Campaign (UIIC) in 2000. All laboratory-confirmed influenza cases in Ontario, from January 1990 to August 2005 were analyzed using multitaper time series analysis. We found that there has not been a decrease in the mean monthly influenza rate following the introduction of the UIIC (109.5 (S.D. 20) versus 160 (S.D. 50.3) p>0.1). Despite increased vaccine distribution and financial resources towards promotion, the incidence of influenza in Ontario has not decreased following the introduction of the UIIC.

The cost-effectiveness of influenza vaccination of healthy adults 50–64 years of age

Influenza can cause significant morbidity and mortality. Influenza vaccination is an effective and safe strategy in the prevention of influenza. Currently the National Health Service (NHS) vaccinates 'at-risk' individuals only. This definition includes everyone over 65 years of age but excludes individuals 50-64 years of age unless they have an additional risk factor, such as underlying heart disease or lung disease. In order to examine the cost-effectiveness of an extension of the vaccination policy to include this age group we constructed an economic model to estimate the costs and benefits of vaccination from both a health service and a societal perspective. Data to populate the model was obtained from the literature and the outcome measure used was the quality adjusted life year (QALY). Influenza vaccination prevented an estimated 4508 cases (95% CI: 2431-7606) per 100,000 vaccinees per influenza season for a net cost to the NHS of pound653,221 (95% CI: 354,575-1,072,257). The net cost increased to pound1,139,069 (95% CI 27,052-2,030,473) when non-NHS costs were included and the estimated cost-per-QALY were pound6174 and pound10,766 for NHS and all costs respectively. Extension of the current immunisation policy has the potential to generate a significant health benefit at a comparatively low cost.

Effects of local variation, specialty, and beliefs on antiviral prescribing for influenza

In 2004, we conducted a survey of physician knowledge, attitudes, and practices regarding influenza diagnosis and treatment at Baystate Medical Center in Massachusetts and Scott & White Hospital and Clinic in Texas. Of the 579 physicians we contacted, 336 completed the survey. Sixty-one percent of the respondents prescribed antivirals, and 62% used rapid testing. Prescribing practices were associated with location, practice size, use of rapid testing, and belief in the efficacy of antivirals.

Colds and Influenza-Like Illnesses in University Students: Impact on Health, Academic and Work Performance, and Health Care Use

BACKGROUND

Upper respiratory tract illnesses (URIs) are a major cause of morbidity among adults, with substantial direct and indirect costs to society, but their impact among university students has not been well described. We sought to assess the impact of URIs (colds and influenza-like illnesses [ILIs]) on the health, academic and work performance, and health care use of university students.

METHODS

This was a cohort study of college students at the University of Minnesota, Twin Cities campus (Minneapolis-St. Paul), who were recruited during October 2002 and followed up from November 2002 through April 2003. All 42,000 registered students were invited via e-mail to participate. Baseline information was obtained in October 2002. Monthly follow-up information about colds or ILIs was obtained for the period of November 2002 through April 2003. Data were collected by use of Internet-based questionnaires.

RESULTS

Of 4919 volunteers, 3249 completed all follow-up surveys. The mean age was 22.7 years; 68% of the volunteers were female. Ninety-one percent had > or = 1 URI (83% had > or = 1 cold, and 36.7% had > or = 1 ILI). These URIs caused 6023 bed-days, 4263 missed school days, 3175 missed work days, and 45,219 days of illness. Of the cohort, 22.2% had > or = 1 health care visit, and 15.8% used antibiotics to treat a URI; 27.8% did poorly on a test and 46.3% did poorly on a class assignment. ILIs versus colds had a much greater impact on all parameters (e.g., general health level was 55%-60% lower with ILI vs. no URI and 33%-39% lower for colds vs. no URI; P < .001 for each).

CONCLUSION

Colds and ILIs were common and associated with substantial morbidity in university students. Enhanced efforts to prevent and control URIs, especially influenza vaccination, could improve the health and well-being of the 17 million college and university students in this country.

Managing febrile respiratory illnesses during a hypothetical SARS outbreak

Since the World Health Organization declared the global outbreak of severe acute respiratory syndrome (SARS) contained in July 2003, new cases have periodically reemerged in Asia. This situation has placed hospitals and health officials worldwide on heightened alert. In a future outbreak, rapidly and accurately distinguishing SARS from other common febrile respiratory illnesses (FRIs) could be difficult. We constructed a decision-analysis model to identify the most efficient strategies for managing undifferentiated FRIs within a hypothetical SARS outbreak in New York City during the season of respiratory infections. If establishing reliable epidemiologic links were not possible, societal costs would exceed 2.0 billion US dollars per month. SARS testing with existing polymerase chain reaction assays would have harmful public health and economic consequences if SARS made up <0.1% of circulating FRIs. Increasing influenza vaccination rates among the general population before the onset of respiratory season would save both money and lives.

Vaccination versus treatment of influenza in working adults: a cost-effectiveness analysis

PURPOSE

To determine the cost-effectiveness of influenza vaccination, antiviral therapy, or no intervention for healthy working adults, accounting for annual variation in vaccine efficacy.

METHODS

We conducted a cost-effectiveness analysis based on published clinical trials of influenza vaccine and antiviral drugs, incorporating 10 years of surveillance data from the World Health Organization. We modeled influenza vaccination, treatment of influenza-like illness with antiviral drugs, or both, as compared with no intervention, targeting healthy working adults under age 50 years in the general community or workplace. Outcomes included costs, illness days, and quality-adjusted days gained.

RESULTS

In the base case analysis, the majority of costs incurred for all strategies were related to lost productivity from influenza illness. The least expensive strategy varied from year to year. For the 10-year period, antiviral therapy without vaccination was associated with the lowest overall costs (234 US dollars per person per year). Annual vaccination cost was 239 US dollars per person, and was associated with 0.0409 quality-adjusted days saved, for a marginal cost-effectiveness ratio of 113 US dollars per quality-adjusted day gained or 41,000 US dollars per quality-adjusted life-year saved compared with antiviral therapy. No intervention was the most expensive and least effective option. In sensitivity analyses, lower vaccination costs, higher annual probabilities of influenza, and higher numbers of workdays lost to influenza made vaccination more cost-effective than treatment. If vaccination cost was less than 16 US dollars or time lost from work exceeded 2.4 days per episode of influenza, then vaccination was cost saving compared with all other strategies.

CONCLUSION

Influenza vaccination for healthy working adults is reasonable economically, and under certain circumstances is cost saving. Antiviral therapy is consistently cost saving.

Antiviral agents for influenza: a comparison of cost-effectiveness data

The economic burden of influenza-related illness has been estimated to be 71.3-166 billion US dollars in the US, the majority of which is attributable to indirect costs as a result of lost productivity. There are currently four antiviral drugs available for the treatment of influenza: two ion channel blockers, amantadine and rimantadine; and two neuraminidase inhibitors, zanamivir and oseltamivir. The objective of this paper was to review the studies evaluating the cost effectiveness of currently available antiviral treatment and prophylaxis management strategies for influenza. Published studies that reported both costs and effectiveness of influenza management were extracted using MEDLINE, pre-MEDLINE and EMBASE. To facilitate a broad comparison, all costs were inflated to 2003 US dollars. Fifteen studies met the inclusion criteria of the review, with 14 analyses based on decision-analytic modelling and one economic analysis performed alongside a clinical trial. Management strategies included antiviral influenza prophylaxis or vaccination, empiric treatment of suspected disease, or antiviral treatment following rapid influenza testing. Study populations included healthy adults, adults at risk of influenza-related adverse outcomes, institutionalised and non-institutionalised elderly, and children. The comparator in all studies was standard care (i.e. over-the-counter medications only), and analyses were carried out from both the societal and payer perspectives. The only dominant strategy relative to standard care was vaccination of the institutionalised elderly. All other strategies in all populations were both more costly and more effective than standard care. Depending on the population and the perspective, the incremental cost-effectiveness ratios (ICERs) for antiviral treatment strategies ranged from 5000 US dollars/QALY for amantadine in test-and-treat studies to >400,000 US dollars/QALY for zanamivir or oseltamivir treatment in children. Sensitivity analysis in all studies consistently reported a strong influence of the population prevalence or diagnostic accuracy of influenza on the cost effectiveness of all strategies. Baseline influenza prevalence varied widely between studies, ranging from 15% to 68%. There was also a wide variation in the assumption about the disutility of influenza (ranging from -0.137 to -0.983 for the elderly requiring hospitalisation), which also impacted the cost effectiveness. Given the variation in the ICERs of antiviral treatment and prophylaxis, the uncertainty around many model parameters, and the dynamic nature of influenza from year to year, one can only conclude that antiviral treatment or prophylaxis for influenza is likely to be more cost effective in specific populations at specific times during the influenza season, and during influenza seasons when the population prevalence reaches epidemic levels or there is mismatch between the vaccine and the circulating virus.

Vaccination practices in U.S. emergency departments, 1992–2000

To determine how frequently emergency department (ED) patients are vaccinated against influenza and pneumococcus, we analyzed all adult ED vaccinations in the combined databases of the annual National Hospital Ambulatory Medical Care Surveys, 1992-2000. During this period, EDs gave 27,738,000 vaccinations (95%CI: 25,878,000-29,598,000). Of these, 93% (87-100%) were against tetanus. The count of pneumococcal or influenza vaccinations was too small to permit estimation of a national total. Large-scale vaccination of ED patients appears feasible, given the tetanus experience, but ED patients are rarely vaccinated against influenza or pneumococcus. Reasons for this disconnect between burden of disease and preventive practices are discussed.

Antiviral therapy for influenza : a clinical and economic comparative review

Each year influenza epidemics cause a considerable burden of disease. Vaccination against influenza A and B viruses has been and remains the cornerstone of influenza prevention, but antiviral therapy can serve as an important adjunct to vaccination in controlling the impact of the disease. Two classes of drugs are currently licensed in a large number of countries for the treatment of influenza. The M2 ion channel blockers or amantadanes (amantadine and rimantadine) are specific inhibitors of influenza A virus replication, whereas the neuraminidase inhibitors (zanamivir and oseltamivir) are active against influenza A and B viruses. Readily transmissible drug-resistant viruses develop frequently during amantadane treatment but not during neuraminidase inhibitor treatment. In this review, efficacy and safety data from randomised controlled trials are evaluated to gain an understanding of what we can and cannot expect from antiviral treatment. All four drugs shorten the course of influenza disease by approximately 1 day and relieve symptoms to some extent, but there is still uncertainty as to whether antiviral therapy leads to a reduction of serious complications and hospitalisation. The results of cost-effectiveness analyses are very diverse, in part because of differences in methodology but also because there is no consensus on what probabilities to assign to the key risks and benefits that form the basis of these studies. Consensus statements by advisory bodies in England and Germany recommend neuraminidase inhibitors for the therapy of influenza in high-risk individuals such as people over 65 years or under 2 years, and individuals with chronic cardiovascular, pulmonary or renal disease, diabetes mellitus or immunosuppression. However, there is no agreement as to whether antiviral therapy can be generally recommended for otherwise healthy children and adults. The availability of safe and effective antiviral therapy options should be kept in mind by the practising clinician, while more specific recommendations and policy formulation will depend on additional efficacy data that include frequency of complications and hospitalisation as outcome measures.

Inactivated Influenza Virus Vaccines in Children

Healthy children aged < or =2 years have hospitalization rates during influenza periods 12 times those of older children and comparable to rates in the elderly population. In 2003, killed influenza vaccines were "recommended" for children with high-risk conditions and were "encouraged" for children aged 6-23 months. Studies involving several thousand children show that split-virus vaccines are safe and immunogenic in healthy children aged > or =6 months and in high-risk children. In children aged < or =9 years, 2 doses of vaccine are required initially to achieve maximum protection. Studies of children aged 6 months to 15 years show vaccine efficacies of 31%-91% against influenza A and 45% against influenza B. Among children attending day care, a reduction in the rate of acute otitis media of 32%-36% was demonstrated. Studies suggest that use of killed vaccines among children is cost-saving. In conclusion, the data show that killed influenza vaccines in children are safe, immunogenic, effective, and potentially cost-saving.

Vaccines for preventing influenza in healthy adults

BACKGROUND

Three different types of influenza vaccines are currently produced worldwide. None is traditionally targeted to healthy adults. Despite the publication of a large number of clinical trials, there is still substantial uncertainty about the clinical effectiveness of influenza vaccines and this has negative impact on the vaccines acceptance and uptake.

OBJECTIVES

To assess the effects of vaccines on influenza in healthy adults. To assess the effectiveness of vaccines in preventing cases of influenza in healthy adults. To estimate the frequency of adverse effects associated with influenza vaccination in healthy adults.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 1, 2004) which contains the Cochrane Acute Respiratory Infections Group trials register; MEDLINE (January 1966 to December 2003); and EMBASE (1990 to December 2003). We wrote to vaccine manufacturers and first or corresponding authors of studies in the review.

SELECTION CRITERIA

Any randomised or quasi-randomised studies comparing influenza vaccines in humans with placebo, control vaccines or no intervention, or comparing types, doses or schedules of influenza vaccine. Live, attenuated or killed vaccines or fractions thereof administered by any route, irrespective of antigenic configuration were considered. Only studies assessing protection from exposure to naturally occurring influenza in healthy individuals aged 14 to 60 (irrespective of influenza immune status) were considered.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data.

MAIN RESULTS

Twenty five reports of studies involving 59,566 people were included. The recommended live aerosol vaccines reduced the number of cases of serologically confirmed influenza by 48% (95% confidence interval (CI) 24% to 64%), whilst recommended inactivated parenteral vaccines had a vaccine efficacy of 70% (95% CI 56% to 80%). The yearly recommended vaccines had low effectiveness against clinical influenza cases: 15%(95% CI 8% to 21%) and 25% (95% CI 13% to 35%) respectively. Overall the percentage of participants experiencing clinical influenza decreased by 6%. Use of the vaccine significantly reduced time off work but only by 0.16 days for each influenza episode (95% CI 0.04 to 0.29 days); Analysis of vaccines matching the circulating strain gave higher estimates of efficacy, whilst inclusion of all other vaccines reduced the efficacy.

REVIEWERS' CONCLUSIONS

Influenza vaccines are effective in reducing serologically confirmed cases of influenza. However, they are not as effective in reducing cases of clinical influenza and number of working days lost. Universal immunisation of healthy adults is not supported by the results of this review.

Management of influenza symptoms in healthy adults

OBJECTIVE

To determine the cost-effectiveness of rapid diagnostic testing and empiric antiviral therapy for healthy adults with symptoms of influenza.

DESIGN

Cost-effectiveness analysis using a decision model based on previously published data. Outcome measures included costs and quality-adjusted life expectancy.

SETTING

Physician's office.

PATIENTS/PARTICIPANTS

Hypothetically healthy, working adults < 65 years of age presenting with cough and fever during the influenza season.

INTERVENTIONS

Rapid testing or clinical diagnosis followed by treatment with amantadine, rimantadine, oseltamivir, or zanamivir compared with no antiviral therapy.

RESULTS

Base-case analysis: not giving antiviral therapy is the most expensive and least effective strategy, costing 471 dollars per patient, mostly owing to time lost from work. Amantadine treatment increases life expectancy by 0.0014 quality-adjusted life years (QALYs) while saving 108 dollars per patient relative to no antiviral therapy. Zanamivir is slightly more effective than amantadine, adding 0.0002 QALYs at an incremental cost of 31 dollars, or 133,000 dollars per QALY saved. All other strategies, including testing strategies, are both less effective and more expensive. SENSITIVITY ANALYSIS: The model is sensitive to the probability of influenza infection, proportion of influenza caused by type B, the relative efficacy of the various drugs, and the value of a workday. At a clinical probability of influenza infection > 20%, antiviral therapy is favored. As the proportion of influenza B increases, zanamivir is favored over amantadine. Testing is rarely indicated. Ignoring the costs of lost workdays, amantadine treatment costs 1,200 dollars/QALY saved.

CONCLUSIONS

Antiviral therapy with either amantadine or zanamivir is cost-effective for healthy, young patients with influenza-like illness during the influenza season, depending on the prevalence of influenza B.

Nosocomial influenza in children

Influenza is the most important cause of acute respiratory illness leading to hospitalization among children during community epidemics. This illness can cause extensive nosocomial outbreaks with serious morbidity and mortality among specific groups of children. Paediatric patients with community-acquired influenza and healthcare workers are the main reservoir for the nosocomial spread of the virus. During epidemics in the community, testing for influenza should be requested in all children with compatible symptoms admitted in the hospital, and measures should be introduced for the prevention or early control of an outbreak. Recent advances in the management of influenza include rapid diagnoses based on antigen detection and the identification of the new neuraminidase inhibitors zanamivir and oseltamivir. Annual vaccination against influenza of children with high-risk conditions, their family members and healthcare workers is the principle measure for the prevention of nosocomial outbreaks. Although vaccination against influenza appears to be cost-effective at all ages in terms of prevention of illness, related hospitalizations, deaths, reduction of healthcare costs and productivity loss, vaccination coverage among target groups is limited.

Pandemic influenza and the global vaccine supply

Use of influenza vaccine is increasing, especially in developing countries. Yet most of the world's influenza vaccine is produced by companies located in 9 developed countries. When the threat of an influenza pandemic appears, the traditional approach to providing interpandemic vaccines will not be able to meet the global demand for pandemic vaccine. Several steps must be taken to address this problem, including the use of reverse genetics to prepare seed strains for vaccine production, the undertaking of clinical studies to define the characteristics of candidate "pandemic-like" vaccines and vaccination schedules, the development of procedures for global vaccine registration, the expansion of recommendations and reimbursement for interpandemic vaccination, the country-specific reporting of vaccine use and forecasts of future vaccine needs, and the negotiation of political agreements that will ensure the adequate production and equitable distribution of pandemic vaccine throughout the world.