RSV vaccine in development: assessing the potential cost-effectiveness in the Dutch elderly population

OBJECTIVES

Respiratory syncytial virus (RSV) is increasingly recognized as an important cause of morbidity, mortality and health-care utilization in the elderly population. A theoretical model was built to assess the levels of vaccine effectiveness and vaccine costs for which a hypothetical RSV-vaccine for Dutch elderly could be cost-effective.

METHODS

Different vaccination strategies were evaluated by changing the levels of vaccine effectiveness and the willingness to pay per quality-adjusted life year gained (QALY). Outcome measures included direct medical costs, QALYs, life years gained, incremental cost-effectiveness ratios (ICERs) and the maximum total vaccination costs per individual (i.e. (vaccine price+administration costs)×nr of doses) while remaining cost-effective.

RESULTS

Using base-case assumptions, it was estimated that vaccination of all persons 60 years and older would prevent 3402GP visits, 2989 antibiotic prescriptions, 535 hospitalizations and 249 deaths and would cost €73,261 per QALY, for a vaccine effectiveness of 70%. Vaccinating only the high risk population of 60 years and older would reduce the estimates to 2042GP visits, 2009 antibiotic prescriptions, 179 hospitalizations and 209 deaths and this reduced the cost per QALY to €34,796 per QALY. Using the same assumptions, the maximum total vaccination costs per individual ranged from €26 when vaccinating all persons 60 and older to €68 when vaccinating only persons aged 85 and above, using a willingness to pay threshold of €50,000 per QALY. For the high risk population aged 60 years and older the estimated maximum total vaccination costs ranged from €52 to €99.

CONCLUSION

Vaccination of Dutch elderly against RSV was found cost-effective for several scenarios. As expected, vaccination is more likely to be cost-effective when only including persons who are at increased risk for contracting RSV or the potential complications of RSV. This theoretical study shows that based on the disease burden in the Dutch population aged 60yrs and older there is potential to develop a vaccine that might be considered cost-effective in the Netherlands.

Hospital-based cluster randomised controlled trial to assess effects of a multi-faceted programme on influenza vaccine coverage among hospital healthcare workers and nosocomial influenza in the Netherlands, 2009 to 2011

Nosocomial influenza is a large burden in hospitals. Despite recommendations from the World Health Organization to vaccinate healthcare workers against influenza, vaccine uptake remains low in most European countries. We performed a pragmatic cluster randomised controlled trial in order to assess the effects of implementing a multi-faceted influenza immunisation programme on vaccine coverage in hospital healthcare workers (HCWs) and on in-patient morbidity. We included hospital HCWs of three intervention and three control University Medical Centers (UMCs), and 3,367 patients. An implementation programme was offered to the intervention UMCs to assess the effects on both vaccine uptake among hospital staff and patient morbidity. In 2009/10, the coverage of seasonal, the first and second dose of pandemic influenza vaccine as well as seasonal vaccine in 2010/11 was higher in intervention UMCs than control UMCs (all p<0.05). At the internal medicine departments of the intervention group with higher vaccine coverage compared to the control group, nosocomial influenza and/or pneumonia was recorded in 3.9% and 9.7% of patients of intervention and control UMCs, respectively (p=0.015). Though potential bias could not be completely ruled out, an increase in vaccine coverage was associated with decreased patient in-hospital morbidity from influenza and/or pneumonia.

Routine screening for Coxiella burnetii infection during pregnancy: a clustered randomised controlled trial during an outbreak, the Netherlands, 2010

Between 2007 and 2010, the Netherlands experienced one of the largest outbreaks of Q fever. Since asymptomatic Coxiella burnetii infection has been associated with maternal and obstetric complications, evidence about the effectiveness of routine screening during pregnancy in outbreak areas is needed. We performed a clustered randomised controlled trial during the Dutch outbreak, in which 55 midwife centres were randomised to recruit pregnant women for an intervention or control strategy. In both groups a serum sample was taken between 20 and 32 weeks of gestation. In the intervention group (n=536), the samples were analysed immediately by indirect immunofluorescence assay for the presence of IgM and IgG (phase I/II) and treatment was given during pregnancy in case of an acute or chronic infection. In the control group (n=693), sera were frozen for analysis after delivery. In both groups 15% were seropositive. In the intervention group 2.2% of the women were seropositive and had an obstetric complication, compared with 1.4% in the control group (Odds ratio: 1.54 (95% confidence interval 0.60-3.96)). During a large Q fever outbreak, routine C. burnetii screening starting at 20 weeks of gestation was not associated with a relevant reduction in obstetric complications and should therefore not be recommended.

The significance of rhinovirus detection in hospitalized children: clinical, epidemiological and virological features

Recent developments in molecular diagnostic tools have led to the easy and rapid detection of a large number of rhinovirus (HRV) strains. However, the lack of clinical and epidemiological data hampers the interpretation of these diagnostic findings. From October 2009 to January 2011, we conducted a prospective study in hospitalized children from whom samples were taken for the detection of respiratory viruses. Clinical, epidemiological and microbiological data from 644 patients with 904 disease episodes were collected. When HRV tested positive, strains were further characterized by sequencing the VP4/VP2 region of the HRV genome. HRV was the single respiratory virus detected in 254 disease episodes (28%). Overall, 99 different serotypes were detected (47% HRV‐A, 12% HRV‐B, 39% HRV‐C). Patients with HRV had more underlying pulmonary illness compared with patients with no virus (p 0.01), or patients with another respiratory virus besides HRV (p 0.007). Furthermore, cough, shortness of breath and a need for oxygen were significantly more present in patients with HRV infection. Particularly, patients with HRV‐B required extra oxygen. No respiratory symptom, except for oxygen need, was predictive of the presence of HRV. In 22% of HRV‐positive disease episodes, HRV infection was hospital acquired. Phylogenetic analysis revealed several clusters of HRV; in more than 25% of these clusters epidemiological information was suggestive of transmission within specific wards. In conclusion, the detection of HRV may help in explaining respiratory illness, particular in patients with pulmonary co‐morbidities. Identifying HRV provides opportunities for timely implementation of infection control measures to prevent intra‐hospital transmission.

Cost-effectiveness of potential infant vaccination against respiratory syncytial virus infection in The Netherlands

INTRODUCTION

Respiratory syncytial virus (RSV) infection is one of the major causes of respiratory illness in infants, infecting virtually every child before the age of 2 years. Currently, several Phase 1 trials with RSV vaccines in infants are ongoing or have been completed. As yet, no efficacy estimates are available for these vaccine candidates. Nevertheless, cost-effectiveness estimates might be informative to enable preliminary positioning of an RSV vaccine.

METHODS

A decision analysis model was developed in which a Dutch birth cohort was followed for 12 months. A number of potential vaccination strategies were reviewed such as vaccination at specific ages, a two- or three-dosing scheme and seasonal vaccination versus year-round vaccination. The impact of the assumptions made was explored in various sensitivity analyses, including probabilistic analysis. Outcome measures included the number of GP visits, hospitalizations and deaths, costs, quality-adjusted life years and incremental cost-effectiveness ratios (ICERs).

RESULTS

Currently, without vaccination, an annual number of 28,738 of RSV-related GP visits, 1623 hospitalizations, and 4.5 deaths are estimated in children in the age of 0-1 year. The total annual cost to society of RSV in the non-vaccination scenario is €7.7 million (95%CI: 1.7-16.7) and the annual disease burden is estimated at 597 QALYs (95%CI: 133-1319). In case all infants would be offered a potentially safe and effective 3-dose RSV vaccination scheme at the age of 0, 1 and 3 months, the total annual net costs were estimated to increase to €21.2 million, but 544 hospitalizations and 1.5 deaths would be averted. The ICER was estimated at €34,142 (95%CI: € 21,652-€ 87,766) per QALY gained. A reduced dose schedule, seasonal vaccination, and consideration of out-of-pocket expenses all resulted in more favorable ICER values, whereas a reduced vaccine efficacy or a delay in the timing of vaccination resulted in less favorable ICERs.

DISCUSSION

Our model used recently updated estimates on the burden of RSV disease in children and it included plausible utilities. However, due to the absence of clinical trial data, a number of crucial assumptions had to be made related to the characteristics of potential RSV vaccine. The outcomes of our modeling exercise show that vaccination of infants against RSV might be cost-effective. However, clinical trial data are warranted.

Screening for Coxiella burnetii infection during pregnancy: pros and cons according to the Wilson and Jungner criteria

In Europe the incidence of human Q fever has dramatically increased over the previous years. Untreated infections with Coxiella burnetii, the causal agent of Q fever, have been associated with both obstetric and maternal complications. The majority of pregnant women with a C. burnetii infection remain asymptomatic, hence screening could be of value to prevent unwanted outcomes in this high-risk group. We applied the updated Wilson and Jungner criteria to review the evidence for routine screening for C. burnetii infection during pregnancy. Since much uncertainty remains about the incidence, clinical consequences, diagnostics and treatment of C. burnetii infection during pregnancy, routine screening for C. burnetii infection during pregnancy should not be recommended. Rigorous studies to assess the effectiveness of C. burnetii screening are warranted.

Screening for Coxiella burnetii infection during pregnancy: pros and cons according to the Wilson and Jungner criteria

In Europe the incidence of human Q fever has dramatically increased over the previous years. Untreated infections with Coxiella burnetii, the causal agent of Q fever, have been associated with both obstetric and maternal complications. The majority of pregnant women with a C. burnetii infection remain asymptomatic, hence screening could be of value to prevent unwanted outcomes in this high-risk group. We applied the updated Wilson and Jungner criteria to review the evidence for routine screening for C. burnetii infection during pregnancy. Since much uncertainty remains about the incidence, clinical consequences, diagnostics and treatment of C. burnetii infection during pregnancy, routine screening for C. burnetii infection during pregnancy should not be recommended. Rigorous studies to assess the effectiveness of C. burnetii screening are warranted.

Placental histopathology after Coxiella burnetii infection during pregnancy

Symptomatic and asymptomatic Coxiella burnetii infection during pregnancy have been associated with obstetric complications. We described placental histopathology and clinical outcome of five cases with asymptomatic C. burnetii infection during pregnancy and compared these cases with four symptomatic cases from the literature. In contrast with the symptomatic cases, we did not observe necrosis or active inflammation in the placentas of the asymptomatic women. Obstetrical outcome was more favourable in the asymptomatic cases than in the symptomatic cases. Asymptomatic and symptomatic C. burnetii infection during pregnancy are different entities with respect to placental histopathology and the risk of obstetric complications.

Determination of factors required to increase uptake of influenza vaccination among hospital-based healthcare workers

A questionnaire study was performed in all eight University Medical Centers in The Netherlands to determine the predictors of influenza vaccination compliance in hospital-based healthcare workers (HCWs). Demographical, behavioural and organisational determinants were assessed based on behavioural and implementation models. Multivariable regression analysis was applied to assess the independent predictors for influenza vaccine uptake. Age >40 years, the presence of a chronic illness, awareness of personal risk and awareness of risk of infecting patients, trust in the effectiveness of the vaccine to reduce the risk of infecting patients, the HCWs' duty to do no harm and their duty to ensure continuity of care, finding vaccination useful despite the constant flow of visitors and having knowledge of the Health Council's advice, social influence and convenient time for vaccination were all independently associated with vaccine uptake. The accuracy of the prediction model was very high (area under the receiver operating curve: 0.95). Intervention programmes to increase influenza vaccine uptake among HCWs should target the relevant determinants identified in this study.

Effects of a multi-faceted program to increase influenza vaccine uptake among health care workers in nursing homes: A cluster randomised controlled trial

Despite the recommendation of the Dutch association of nursing home physicians (NVVA) to be immunized against influenza, vaccine uptake among HCWs in nursing homes remains unacceptably low. Therefore we conducted a cluster randomised controlled trial among 33 Dutch nursing homes to assess the effects of a systematically developed multi-faceted intervention program on influenza vaccine uptake among HCWs. The intervention program resulted in a significantly higher, though moderate, influenza vaccine uptake among HCWs in nursing homes. To take full advantage of this measure, either the program should be adjusted and implemented over a longer time period or mandatory influenza vaccination should be considered.

Which factors are important in adults' uptake of a (pre)pandemic influenza vaccine?

Since 2008, (pre)pandemic vaccines against H5N1 influenza have been available and pandemic vaccines against new influenza H1N1 are currently produced. In The Netherlands, the vaccination call for seasonal influenza among the recommended groups approximates 70%. These statistics raise the question if adults in Western societies are willing to get a (pre)pandemic influenza vaccination, for example, against avian H5N1 or swine-like H1N1 virus. A questionnaire was performed to determine the predictors of a negative intention to be immunized against pandemic influenza among adults. Demographical, behavioural and organisational determinants were studied. Thirty-four and five percent of the respondents were negatively intended to get a pandemic influenza vaccination in a pre-pandemic or pandemic phase, respectively. On the basis of six behavioural determinants negative intention to get a pandemic influenza vaccination can be predicted correctly in almost 80% of the target group. These determinants should be targeted in pandemic preparedness plans.

Modeling the effects of influenza vaccination of health care workers in hospital departments

Nowadays health care worker (HCW) vaccination is widely recommended. Although the benefits of this strategy have been demonstrated in long-term care settings, no studies have been performed in regular hospital departments. We adapt a previously developed model of influenza transmission in a long-term care nursing home department to study the effects of HCW vaccination in hospital wards. We study both the effectiveness and efficiency in reducing the hazard rates of influenza virus infection for patients. Most scenarios under study show a similar or higher impact of hospital HCW vaccination than has been predicted for the long-term care nursing home department. Therefore, it seems justified to extend the recommendations for HCW vaccination, based on results in the long-term care setting, to short-term care settings as well.

Time for first antibiotic dose is not predictive for the early clinical failure of moderate-severe community-acquired pneumonia

The time to first antibiotic dose (TFAD) has been mentioned as an important performance indicator in community-acquired pneumonia (CAP). However, the advice to minimise TFAD to 4 hours (4 h) is only based on database studies. We prospectively studied the effect of minimising the TFAD on the early clinical outcome of moderate–severe CAP. On admission, patients’ medical data and TFAD were recorded. Early clinical failure was expressed as the proportion of patients with clinical instability, admission to the intensive care unit (ICU) or mortality on day three. Of 166 patients included in the study, 27 patients (29.7%) with TFAD <4 h had early clinical failure compared to 23 patients (37.7%) with TFAD >4 h (odds ratio [OR] 0.69; 95% confidence interval [CI] 0.35–1.35). In multivariate analysis, the pneumonia severity index (OR 1.03; 95%CI 1.01–1.04), confusion (OR 2.63; 95%CI 1.14–6.06), Staphylococcus aureus infection (OR 7.26; 95%CI 1.33–39.69) and multilobar pneumonia (OR 2.40; 95%CI 1.11–5.22) but not TFAD were independently associated with early clinical failure. Clinical parameters on admission other than the TFAD predict early clinical outcome in moderate–severe CAP. In contrast to severe CAP necessitating treatment in the ICU directly, in the case of suspected moderate–severe CAP, there is time to establish a reliable diagnosis of CAP before antibiotics are administered. Therefore, the implementation of the TFAD as a performance indicator is not desirable.

Incidence and antibiotic prescription rates for common infections in patients with diabetes in primary care over the years 1995 to 2003

OBJECTIVE

To assess changes in incidence and in antibiotic prescription rates for infections of the lower respiratory tract (LRTI) and urinary tract (UTI) in patients with diabetes (DM) over the years 1995 to 2003.

METHODS

This was a retrospective cohort study as part of the University Medical Center Utrecht General Practitioners Research Network. We included patients with DM aged > or = 45 years. We assessed incidence and antibiotic prescription rates for LRTI and UTI. Incidence rates were calculated as episodes per 1000 person-years. Antibiotic prescription rates were calculated per 100 episodes of LRTI and UTI.

RESULTS

The study population increased over the years 1995 to 2003. The male-to-female ratio and mean age of the study population remained constant over these years. The incidence rate for LRTI remained stable (13%; p=0.442), and for UTI the incidence rate increased by 40% (p=0.037). Antibiotic prescription rates increased in LRTI by 60% (p<0.001) and in cystitis by 15% (p=0.029).

CONCLUSIONS

Incidence rates for UTI and antibiotic prescription rates for LRTI in diabetes have increased over the years 1995 to 2003. In particular, attention should be paid to the increasing use of antibiotics in DM patients with LRTI.

Excess drug prescriptions during influenza and RSV seasons in the Netherlands: potential implications for extended influenza vaccination

Influenza and respiratory syncytial virus (RSV) infections are responsible for considerable morbidity, mortality and health-care resource use. For the Netherlands, we estimated age and risk-group specific numbers of antibiotics, otologicals and cardiovascular prescriptions per 10,000 person-years during periods with elevated activity of influenza or RSV, and compared these with peri-season rates. Data were taken from the University of Groningen in-house prescription database (www.iadb.nl) and virological surveillance for the period 1998-2006. During influenza and RSV periods excess antibiotic prescriptions were estimated for all age groups. In the age groups 0-1 and 2-4 years, excess antibiotic prescriptions during periods with elevated RSV activity (65% and 59% of peri-seasonal rates) exceeded the surpluses estimated during the influenza-activity periods (24% and 34% of peri-seasonal rates) while for otologicals excess prescriptions were higher for influenza (22% and 27%) than for RSV (14% and 17%). Among persons of 50 years and older, notably those without medical high-risk conditions, excess prescriptions for cardiovascular medications were estimated during the influenza periods at approximately 10% (this was also already seen in persons aged 45-49). Our results may have implications for influenza vaccination policies. In particular, extension of influenza vaccination to groups of non-elderly adults and young children may lower excess prescriptions during these influenza periods for all three types of drug prescriptions investigated.

Symptoms of influenza virus infection in hospitalized patients

BACKGROUND

During influenza outbreaks, fever and cough are the most accurate symptoms in predicting influenza virus infection in the community.

OBJECTIVE

To determine the usefulness of fever, cough, and other symptoms for diagnosing influenza virus infection in hospitalized patients.

DESIGN

Prospective cohort study.

SETTING

Three wards (pulmonology, internal medicine and infectious diseases, and geriatrics) of a tertiary care hospital in the Netherlands.

PATIENTS

All patients staying in the wards during peak national influenza activity in the 2005-2006 and 2006-2007 influenza seasons.

METHODS

During peak influenza activity, the presence of fever, cough, and/or other symptoms possibly associated with influenza was monitored for all patients, and nose and throat swab samples were taken twice weekly for virologic analysis.

RESULTS

Of 264 patients, 23 (9%) tested positive for influenza virus. The positive predictive value of fever and cough for the diagnosis of influenza virus infection was 23% (95% confidence interval, 0%-62%), and the sensitivity was 35% (95% confidence interval, 11%-58%). The combination of symptoms with the highest positive predictive value (40%) was that of cough, chills, and obstructed nose or coryza. The combination of cough and chills or fever had the highest sensitivity (60%). None of the combinations of symptoms had both a positive predictive value and a sensitivity higher than 40%.

CONCLUSIONS

Both the sensitivity and the positive predictive value of fever, cough, and/or other symptoms for the diagnosis of influenza virus infection in hospitalized patients are low. The use of these common symptoms for treatment decisions and infection control management will probably be insufficient to contain a nosocomial outbreak, because many influenza cases will remain unidentified.

Collaborative efforts are needed to improve use of influenza immunisation in Europe

Influenza is among the infectious diseases with the highest incidence and associated serious morbidity and mortality that can be prevented by vaccination.

Rationale and design of CAPITA: a RCT of 13-valent conjugated pneumococcal vaccine efficacy among older adults

The burden of community-acquired pneumonia (CAP) among the elderly is high and has increased over the last decades. Streptococcus pneumoniae is the most common cause of CAP and in 10% the infection may be fatal. Although the 23-valent polysaccharide pneumococcal vaccine (23vPS) is considered effective in the prevention of invasive pneumococcal disease in the elderly population, the evidence is mainly from nonrandomised observational studies and effects on the occurrence of pneumonia have not been demonstrated. Conjugated pneumococcal vaccines which also stimulate T-cell dependent immune responses induced antibody responses in elderly persons which are similar to those induced by a primary series of 7-valent conjugated pneumococcal vaccine (7vPnC) in infants, and the response appeared similar or superior for all vaccine serotypes to that induced by 23vPS. The primary objective of the planned trial entitled CAPITA (Community Acquired Pneumonia Immunization Trial in Adults) is to establish the efficacy of a 13-valent PnC vaccine in the prevention of a first episode of vaccine-serotype specific pneumococcal CAP in 85,000 community-dwelling adult persons aged 65 years and older. This is a parallel group, randomised, placebo-controlled trial, with a 1:1 random allocation to vaccine or placebo vaccine. The occurrence of the primary outcome of vaccine-serotype specific (VT)-CAP will be established in hospitals on the basis of three sets of criteria: (1) a clinical definition of CAP; (2) independent interpretation of chest radiograph consistent with pneumonia: and (3) determination of S. pneumonia serotype. the trial will be critical to determine the position of conjugate pneumococcal vaccines in the prevention of pneumococcal disease.

Quantifying the potential role of unmeasured confounders: the example of influenza vaccination

BACKGROUND

The validity of non-randomized studies using healthcare databases is often challenged because they lack information on potentially important confounders, such as functional health status and socioeconomic status. In a study quantifying the effects of influenza vaccination among community-dwelling elderly we assessed whether additional information on not routinely available covariates was indeed associated with exposure to influenza vaccination and could, therefore, have led to residual confounding in healthcare databases.

METHODS

We randomly selected 500 persons aged 65 years and older from the computerized Utrecht General Practitioner database. Information on exposure status and on demographics, co-morbidity status, prior healthcare use and medication use was extracted from the database. A questionnaire was used to obtain additional information on not routinely available risk factors [e.g. functional health status (SF-20), smoking status and alcohol consumption]. Missing data from the questionnaire was imputed and multivariable logistic regression analysis was applied to quantify the influence of covariates on the prediction of exposure to influenza vaccination. Within an existing dataset the potential impact of functional health status on the relation between influenza vaccination and mortality was simulated.

RESULTS

We obtained questionnaire data from 365 of 500 (73%) subjects. The model including routinely available data from the database appeared accurate in predicting exposure to influenza vaccination (c-statistic 0.86, 95% CI: 0.82-0.89). Functional health status was the only additional characteristic measured with the questionnaire that was not similar in vaccinated and unvaccinated subjects. However, extending the multivariable regression model with functional health status did not significantly improve the prediction of exposure to influenza vaccination, nor did it affect the relation between influenza vaccination and mortality.

CONCLUSION

The potential for unmeasured confounding on the association between influenza vaccination and health outcomes as quantified in healthcare databases seems small for non-randomized intervention studies within extensive and reliable databases.