Is vaccination against measles, mumps, and rubella associated with reduced rates of antibiotic treatments among children below the age of 2 years? Nationwide register-based study from Denmark, Finland, Norway, and Sweden

OBJECTIVES

Previous studies have shown that vaccination against measles, mumps, and rubella (MMR) may have beneficial non-specific effects, reducing the risk of infections not targeted by the vaccine. We investigated if MMR vaccine given after the third dose of diphtheria-tetanus-acellular pertussis vaccine (DTaP3), was associated with reduced rates of antibiotic treatments.

METHODS

Register-based cohort study following children from the age of recommended MMR vaccination until age 2 years. We included 831,287 children born in Denmark, Finland, Norway, and Sweden who had received DTaP3 but not yet MMR vaccine. Cox proportional hazards regression with age as the underlying timescale and vaccination status as a time-varying exposure was used to estimate covariate-adjusted Hazard Ratios (aHRs) and inverse probability of treatment weighted (IPTW) HRs of antibiotic treatments. Summary estimates were calculated using random-effects meta-analysis.

RESULTS

Compared with only having received DTaP3, receipt of MMR vaccine after DTaP3 was associated with reduced rates of antibiotic treatments in all countries: the aHR was 0.92 (0.91-0.93) in Denmark, 0.92 (0.90-0.94) in Finland, 0.84 (0.82-0.85) in Norway, and 0.87 (0.85-0.90) in Sweden, yielding a summary estimate of 0.89 (0.85-0.93). A stronger beneficial association was seen in a negative control exposure analysis comparing children vaccinated with DTaP3 vs two doses of DTaP.

CONCLUSIONS

Across the Nordic countries, receipt of MMR vaccine after DTaP3 was associated with an 11% lower rate of antibiotic treatments. The negative control analysis suggests that the findings are affected by residual confounding. Findings suggest that potential non-specific effects of MMR vaccine are of limited clinical and public health importance for the milder infections treated out-of-hospital in the Nordic setting.

High-Dose Quadrivalent Influenza Vaccine for Prevention of Cardiovascular and Respiratory Hospitalizations in Older Adults

BACKGROUND

We assessed the relative vaccine effectiveness (rVE) of high-dose quadrivalent influenza vaccine (QIV-HD) versus standard-dose quadrivalent influenza vaccine (QIV-SD) in preventing respiratory or cardiovascular hospitalizations in older adults.

METHODS

FinFluHD was a phase 3b/4 modified double-blind, randomized pragmatic trial. Enrolment of 121,000 adults ≥65 years was planned over three influenza seasons (October to December 2019-2021). Participants received a single injection of QIV-HD or QIV-SD. The primary endpoint was first occurrence of an unscheduled acute respiratory or cardiovascular hospitalization (ICD-10 primary discharge J/I codes), from ≥14 days post-vaccination until May 31. The study was terminated after one season due to COVID-19; follow-up data for 2019-2020 are presented.

RESULTS

33,093 participants were vaccinated (QIV-HD, n = 16,549; QIV-SD, n = 16,544); 529 respiratory or cardiovascular hospitalizations (QIV-HD, n = 257; QIV-SD, n = 272) were recorded. The rVE of QIV-HD versus QIV-SD to prevent respiratory/cardiovascular hospitalizations was 5.5% (95% CI, -12.4 to 20.7). When prevention of respiratory and cardiovascular hospitalizations were considered separately, rVE estimates of QIV-HD versus QIV-SD were 5.4% (95% CI, -28.0 to 30.1) and 7.1% (95% CI, -15.0 to 25.0), respectively. Serious adverse reactions were <0.01% in both groups.

CONCLUSIONS

Despite insufficient statistical power due to the impact of COVID-19, rVE point estimates demonstrated a trend toward a benefit of QIV-HD over QIV-SD. QIV-HD was associated with lower respiratory or cardiovascular hospitalization rates than QIV-SD, with a comparable safety profile. Adequately powered studies conducted over multiple influenza seasons are needed to determine statistical significance of QIV-HD compared with QIV-SD against preventing respiratory and cardiovascular hospitalizations.

TRIAL REGISTRATION

ClinicalTrials.gov number: NCT04137887.

Cohort Profile: Childhood morbidity and potential non-specific effects of the childhood vaccination programmes in the Nordic countries (NONSEnse): register-based cohort of children born 1990-2017/2018

PURPOSE

The aim of the NONSEnse project is to investigate the non-specific effects of vaccines and immunisation programmes on the overall health of children by using information from the extensive nationwide registers on health and sociodemographic factors in Denmark, Finland, Norway and Sweden.

PARTICIPANTS

The cohort covers 9 072 420 children aged 0-17 years, born 1990-2017/2018 and living in Denmark, Finland, Norway or Sweden. All countries use a unique identification number for its permanent residents, which makes it possible to link individual-level information from different registers.

FINDINGS TO DATE

Data collection and harmonisation according to a common data model was completed in March 2022. As a prerequisite for comparing the effects of childhood vaccinations on the overall health of children across the Nordic countries, we have identified indicators measuring similar levels of infectious disease morbidity across these settings. So far, studies pertaining to non-specific effects of vaccines are limited to investigations that could be undertaken using aggregated data sets that were available before the NONSEnse cohort with individual-level information was completely set up.

FUTURE PLANS

We are currently performing several studies of the effects on non-targeted infectious disease morbidity across the countries following vaccination against measles, mumps, rubella, diphtheria, tetanus, pertussis, human papillomavirus, rotavirus and influenza. Multiple studies are planned within the next years using different study designs to facilitate triangulation of results and enhance causal inference.

REGISTRATION

No clinical trials will be conducted within the NONSEnse project.

A retrospective nationwide register-based study to evaluate the non-specific effects of first MMR vaccination among children in Finland

BACKGROUND

According to earlier studies, live vaccines like measles-mumps-rubella (MMR) vaccine could reduce also other infections than only the infections they are targeted against. This non-specific effect has been seen especially in studies in low-income countries and results from high-income countries have not been unambiguous. In 2011 Finland changed the recommended schedule for the first MMR vaccination from 18 months to 12 months of age. This change created a natural experiment for evaluating the potential non-specific effects.

METHODS

This is a retrospective nationwide register-based cohort study of Finnish children born between 2008 and 2012. Children were divided into two cohorts by age at MMR vaccination: children administered early MMR vaccination (11 through 12 months of age) and late MMR vaccination (18 through 19 months of age). Morbidity was evaluated during the main follow-up period (from 13 to 17 months of age) and before any MMR vaccination (3 to 10 months) and after all were vaccinated with MMR (20 to 35 months) as control follow-up periods. We analyzed all infections and did additional analyzes for urinary tract infections (UTI) and bronchitis. Injuries were analyzed as a control outcome.

RESULTS

Early MMR vaccinated children (N = 79949) had fewer infections compared to late MMR vaccinated (N = 60965) during the main follow-up period. The incidence rate ratio (IRR) was 0.84 (95 % confidence interval (95 % CI) 0.81-0.87). However, similar differences were also observed during the control follow-up periods. MMR vaccinated children had less UTI in the main follow-up period (IRR 0.73, 0.60-0.89) but not in the control follow-up periods. When stratified by sex, the difference was observed among girls but not in boys.

CONCLUSION

No clear evidence was found for non-specific effects in infectious diseases morbidity. However, there could be a nonspecific effect on UTI. Confirmation is needed from other studies, especially from high-income countries.

Time and labour costs of preventive health care, including vaccinations, in Finnish child health clinics

In Finland all children are entitled to regular health check-up visits at child health clinics (CHC). During the visits public health nurses and physicians follow-up the growth and development of the child, evaluate the welfare of the family, give health counselling and vaccinate the children. The aim of this study was to measure the time used by the nurses and physicians for different tasks during the visits and evaluate the costs of preventive health care procedures. Special emphasis was on time and costs used for administering vaccinations. The study was conducted in four CHCs. Trained observers measured the time used for predefined tasks with a stopwatch application operating on a tablet computer. Labour costs of visits and vaccinations were evaluated by using the gross average salary costs of health care personnel. Time used for vaccine logistics and other administrative tasks was obtained by interviewing the nurses in charge of the vaccine logistics at each CHC. Altogether 325 CHC visits of children <13 months were followed. Public health nurse used for a visit in average 49 (range 12-101) minutes, and the corresponding labour costs were 17 (4-35) Euros. Vaccines were administered at 183 visits. Children got on average 2.4 (1-4) vaccine doses per visit. The observed time used for vaccinations was 10.2 (1.6-25) minutes and the costs 3.58 (0.57-8.62) Euros per visit. The observed time included guidance, preparation, administration, and documentation of vaccinations. Adding one dose into a visit increased the time spent on vaccination on average 2.8 minutes (0.99 Euros). The mean non-observed time used for vaccine logistics outside the visits was 3.4 minutes and cost 1.19 Euros per dose. Administering of the vaccines of the Finnish vaccination programme is relatively simple and inexpensive because Finnish children have regular scheduled visits to CHCs.

Trends in Antibiotic Use in Danish, Finnish, Norwegian and Swedish Children

Objective

To compare the use of antibiotics in children in four Northern European countries.

Methods

We conducted a register-based study based on individual-level prescription data from national prescription registers. We identified all redeemed outpatient prescriptions for systemic antibiotics in children aged 0–14 years from July 2006 to June 2017 in Denmark, Finland, Norway, and Sweden. We computed incidence rates and incidence rate ratios of treatment episodes with any antibiotic and different antibiotic classes.

Results

In 2016/2017, the rates of antibiotic treatment episodes per 1000 person-years in children aged 0–14 years were 429, 284, 219, and 184 in Finland, Denmark, Sweden, and Norway, respectively, and the rate ratios (95% confidence intervals) compared with Norway were 2.33 (2.33–2.34), 1.54 (1.54–1.55), and 1.19 (1.19–1.20) in Finland, Denmark, and Sweden, respectively. The rate of antibiotic treatment episodes declined over time in all countries. The relative reductions in 2016/2017 compared with 2006/2007 were 36% in Finland, 40% in Denmark, 49% in Sweden, and 29% in Norway. Treatment episodes peaked between age 12 and 18 months. The most used antibiotic class was beta-lactamase sensitive penicillins among all children in Norway and Sweden and among children above two years in Denmark, while penicillins with extended spectrum were most used in Finland and among the youngest children in Denmark.

Conclusion

In all countries, the use of antibiotics in children declined between 2006 and 2017. However, there were still considerable differences in antibiotic use between otherwise quite similar Nordic countries, with a more than 2-fold difference between the countries with the lowest and highest rates. Interventions to reduce the number of antibiotic treatment episodes in the countries with higher rates could reduce the total antibiotic use.

Development process of artificial intelligence based chatbot to support and promote mental wellbeing in sparsely populated areas of five European countries

Introduction

In many countries, people face problems regarding access to care, 24/7 support and evidence-based support. Digital interventions and services, such as chatbots, can be one option to tackle these challenges. There is a lack knowledge regarding how mental health chatbots are developed and how to ensure that there is collaboration between mental health and digital technology experts and users.

Objectives

This presentation describes the phases of the development for the ChatPal mental health and wellbeing chatbot.

Methods

Development process was conducted in five and with four different languages. First, using an electronic survey for mental health professionals (n =190) we screened how familiar they are with chatbots and how they evaluated their potential. Second, university students and staff, mental health professionals and service users (n=78) participated in workshops to design the chatbot content. Finally, the content and scripts of chatbot were written in multi-professional and multi-national collaboration.

Results

ChatPal is based on the PERMAH model of positive psychology and on the idea that we all have mental health which needs boosting and support from time to time. ChatPal includes relevant mental health information, exercises, mood diaries and simple monitoring and self-care tools. Based on preliminary evaluations, the ChatPal chatbot offers an option to offer support in areas where other mental health services are lacking or are insufficient.

Conclusions

ChatPal is already freely available in application stores and first scientific trials are have started. Preliminary results of 4-week and subsequent 12-week in-the-wild trials will be in place at the time of EPA 2022 conference.

Disclosure

No significant relationships.

Coproducing multilingual conversational scripts for a mental wellbeing chatbot - where healthcare domain experts become chatbot designers

Introduction

Digital mental health interventions, such as chatbots that promote mental health and wellbeing are a promising way to deliver low-threshold support 24/7 for those in need. According to current knowledge about the topic, health care professionals should participate in the design and development processes for digital interventions.

Objectives

The aim of this presentation is to describe the interdisciplinary content development process of the ChatPal chatbot.

Methods

The content development process started in co-operation with mental health professionals and potential users to identify requirements. Content was created, evaluated and tested in international, multi-disciplinary group workshops, and online tools were used to allow the collaboration. Initial conversational scripts were drafted in English, and translated into Finnish, Swedish and Scottish Gaelic.

Results

A multilingual chatbot was developed and the conversation scripts were structured and stored using a spreadsheet. The conversation scripts will be made freely available online in due course using this structured approach to formatting chatbot dialogue content. It will allow repurposing the content as well as facilitating studies that wish to assess the design of conversation scripts for mental health chatbots. Conversation design process also highlighted some challenges in turning empathetic and supportive conversations to short utterances suitable for a chatbot.

Conclusions

The ChatPal chatbot is now available in four languages. As literature about the topic is still scarce, it is important to describe and document the content development processes of mental health chatbots. Future work will develop a conversational UX toolkit that would allow health professionals to design chatbot scripts using design guidelines.

Disclosure

No significant relationships.

Hospital Contacts for Infectious Diseases Among Children in Denmark, Finland, Norway, and Sweden, 2008-2017

Purpose

Comparing rates of childhood infectious disease hospitalisations across countries may uncover areas for improvement in the prevention of severe childhood infections. We compared rates of childhood infectious disease hospital contacts across Denmark, Finland, Norway, and Sweden with the overall objective to elucidate potential differences in burden of disease and in organisational and registration practices.

Methods

Using national registries, we estimated incidence rates for infectious disease hospital contacts between 2008 and 2017 among children aged 0–14 years. We investigated the rates for different types of contacts (inpatient or outpatient including emergency room), duration of admission, and by sex.

Results

During the study period, the rate of all hospital contacts per 1000 person-years was highest in Sweden (125.2) followed by Finland (87.1), Denmark (79.0), and Norway (62.1). The rates aligned for inpatient contacts with overnight stays; 19.3 (Denmark), 16.6 (Finland), 16.3 (Norway), and 13.0 (Sweden); these were highest in early infancy in all countries. A peak around 1 year of age was seen in all countries except in Sweden. The rates were higher among boys compared with girls in early childhood, after 13 years of age the rates among girls surpassed the boys.

Conclusion

Large cross-country differences were observed for outpatient and short-term hospital contacts for infectious diseases, affected by differences in organisational structures and coding practices across and within countries over time. Inpatient contacts requiring overnight stays reflected more comparable levels of severe infections across countries. Childhood infectious disease morbidity was greatest among boys and before 2 years of age.

Chatbots to Support Mental Wellbeing of People Living in Rural Areas: Can User Groups Contribute to Co-design?

Digital technologies such as chatbots can be used in the field of mental health. In particular, chatbots can be used to support citizens living in sparsely populated areas who face problems such as poor access to mental health services, lack of 24/7 support, barriers to engagement, lack of age appropriate support and reductions in health budgets. The aim of this study was to establish if user groups can design content for a chatbot to support the mental wellbeing of individuals in rural areas. University students and staff, mental health professionals and mental health service users (N = 78 total) were recruited to workshops across Northern Ireland, Ireland, Scotland, Finland and Sweden. The findings revealed that participants wanted a positive chatbot that was able to listen, support, inform and build a rapport with users. Gamification could be used within the chatbot to increase user engagement and retention. Content within the chatbot could include validated mental health scales and appropriate response triggers, such as signposting to external resources should the user disclose potentially harmful information or suicidal intent. Overall, the workshop participants identified user needs which can be transformed into chatbot requirements. Responsible design of mental healthcare chatbots should consider what users want or need, but also what chatbot features artificial intelligence can competently facilitate and which features mental health professionals would endorse.

Revaccination with measles-mumps-rubella vaccine and hospitalization for infection in Denmark and Sweden - An interrupted time-series analysis

BACKGROUND

In a previous cohort study of 4-year-old Danish children, revaccination with the live measles-mumps-rubella vaccine (MMR) was associated with a 16% reduction in the rate of hospitalization lasting two days or longer for non-measles-mumps-rubella infections.

AIM

To examine if the introduction of revaccination with MMR at 4 years of age in Denmark (spring 2008) and at 7-9 years of age in Sweden (autumn 2009), at a time when there was virtually no measles, mumps or rubella cases, was associated with a reduction in the rate of hospitalization-for-infection lasting two days or longer at the population level.

METHODS

We included 4-year-olds in Denmark and 7-9-year-olds in Sweden. We obtained the number of hospitalization-for-infection lasting two days or longer from nationwide hospital registers. Person-years at risk were approximated from population statistics for each season and year. We performed an interrupted time series analysis using Poisson regression to estimate the change in hospitalization incidence rates following the introduction of MMR revaccination, adjusting for seasonality. We also performed analyses with control series (3-year-olds in Denmark and 4-year-olds in Sweden).

RESULTS

Comparing the incidence of hospitalization-for-infection lasting two days or longer after the introduction of MMR revaccination with the expected level without an introduction of MMR revaccination resulted in an incidence rate ratio of 1.07 (95% confidence interval [CI] = 0.89-1.28) for 4-year-olds in Denmark and 0.89 (95% CI = 0.77-1.02) for 7-9-year-olds in Sweden in analyses without controls. Analyses with controls gave similar results.

CONCLUSION

This population-level study of the introduction of MMR revaccination in Denmark and Sweden had inadequate power to confirm or refute the findings from an individual-level Danish study of an association between MMR revaccination and a lower incidence rate of hospitalization-for-infection lasting two days or longer.

Long-term Social Outcomes After Congenital Heart Surgery

BACKGROUND

Patients are surviving decades after congenital heart surgery (CHS), raising the importance of postoperative quality of life as an outcome measure. We determined the long-term social outcomes after CHS performed during childhood.

METHODS

Between 1953 and 2009, 10 635 patients underwent surgery for congenital heart defects at <15 years of age in Finland. We obtained 4 control subjects per patient, matched by age, sex, birth time, and hospital district, from Statistics Finland, which also provided data on the highest education level, employment status, marital status, and progeny for both patients and control subjects. We included patients who were alive and ≥18 years of age at the end of the follow-up on December 31, 2017.

RESULTS

A total of 7308 patients met inclusion criteria. Patients had on average similar high school or vocational education rates as the general population but lower undergraduate or higher education rates (female patients: risk ratio [RR] 0.8 [95% confidence interval (CI) 0.8-0.9]; male patients: RR 0.8 [95% CI 0.7-0.9]). Patients were less likely to be married or have progeny compared with the general population. The rate of employment was significantly lower (female patients: RR 0.8 [95% CI 0.8-0.9]; male patients: RR 0.8 [95% CI 0.8-0.9]) and the rate of retirement (female patients: RR 2.1 [95% CI 2.0-2.3]; male patients RR 3.1 [95% CI 2.9-3.5]) significantly higher among patients.

CONCLUSIONS

Patients who undergo CHS at childhood age are, on average, more disadvantaged from both an educational and professional standpoint compared with the general population, regardless of the severity of the defect.

THU0059 INCREASING SURFACE LUBRICATION WITH POLY(2-METHYL-2-OXAZOLINE) HALTS DEGENERATIVE CHANGES IN THE CARTILAGE IN A COLLAGENASE INDUCED OSTEOARTHRITIS (CIOA) RAT MODEL

Background:

Degenerative lesions of articular cartilage (AC) surface are related to disruption of the well-organized collagen network and allow proteoglycans to escape from the tissue. Ultimately, this leads to the development of osteoarthritis (OA). Targeted therapy for early AC lesions could provide an effective way to halt the OA development process.

Objectives:

This study aims to evaluate the effectiveness of an engineered surface lubricant; poly(2-methyl-2-oxazoline) (PMOXA)1to prevent the destruction of the AC surface. Our recently developed contrast-enhanced µCT (CEµCT) method was used to quantify AC surface erosion2.

Methods:

OA was induced in 12-18 week-old male Wistar rats (N=17) with an injection of 250 U Collagenase within 25 µL solution into the left hind limb. Both hind legs were treated with a second injection three days after the collagenase injection (CI). Three groups were formed by using either PMOXA (N=5), hyaluronic acid (HA; N=6), or saline (N=6) during the second injection. The animals were sacrificed after 45 days, and harvested knees were fixed in phosphate-buffered formalin for a week. Knees were stored in 70% ethanol, and tibia and femur were carefully dissected free of other tissue, stained with 1% phosphotungstic acid3, and scanned with a desktop µCT with 2.8µm pixel size. The medial and lateral AC surfaces were manually segmented from 3D projections using an in-house developed program (Matlab sofware). These surfaces were analyzed by iteratively fitting a reference surface (RS) to a median-filtered smoothed surface representing a perfectly smooth surface, capturing the realistic shape AC. An offset of 5 pixels (14 µm) was added between the RS and the original surface (OS). Two quantitative parameters were calculated from the data: Average of Maximum Void Depth (MVD) (depth of lesion) and Degeneration-% (area exceeding 20 µm MVD / whole area) *100). Estimates of mean differences from all groups against the CI+Saline -group were determined using a linear mixed model.

Results:

Boxplots from tested groups are shown in Fig. 1A and MVD results are visualized in Fig. 1B. Collagenase caused structural defects only on the medial and lateral tibial AC surfaces, which was seen as increased MVD and Degeneration-%. CI changes were not seen in PMOXA or HA treated groups. Furthermore, MVD and Degeneration% were lower in CI knees that were treated with PMOXA.

Figure 1.

A) Boxplots of Maximum Void Depth (MVD) and Degeneration-%. Lateral and medial side are analyzed separately for both tibias and femurs. Stars indicate if a group was statistically different from control group (CI+Saline).CI= red, no CI= blue. B) Representative visualizations for maximum void depth overlayed on top of the 3D AC surface.

Conclusion:

Our CEµCT analysis method was able to detect subtle changes of the AC surface in the medial and lateral tibial cartilage, caused by the CI. In contrast, the CI did not cause detectable changes in the AC of the femur, which indicates that in the CIOA model, the tibia is more susceptible to structural degradation. Our results show that early intervention with HA or PMOXA can halt the degenerative AC changes caused by CI. However, HA did not suppress the effects of CI in the medial tibia, which indicates that PMOXA could be more effective to prevent the development of OA.

References:

[1]Morgese G, et al. Hairy and slippery polyoxazoline-based copolymers on model and cartilage surfaces. Biomacromolecules 2018 19 (2), 680-690

[2]Ylitalo T, et al. Quantifying Complex Micro-Topography of Degenerated Articular Cartilage Surface by Contrast-Enhanced Micro-Computed Tomography and Parametric Analyses. J Orthop Res. 2019 Apr;37(4):855-866.

[3]Nieminen HJ, et al. Determining collagen distribution in articular cartilage using contrast-enhanced micro-computed tomography. Osteoarthritis Cartilage. 2015;23(9):1613–1621

Disclosure of Interests:

None declared

Chronic Disease Burden After Congenital Heart Surgery: A 47-Year Population-Based Study With 99% Follow-Up

Background Postoperative morbidity is an increasingly important outcome measure of patients who have undergone congenital heart surgery (CHS). We examined late postoperative morbidity after CHS on the basis of patients' government-issued medical special reimbursement rights. Methods and Results Between 1953 and 2009, 10 635 patients underwent CHS at <15 years of age in Finland. We excluded early deaths and mental disabilities. Noncyanotic and cyanotic defects were divided into simple and severe groups, respectively. We obtained 4 age-, sex-, birth time-, and hospital district-matched control subjects per patient. The Social Insurance Institution of Finland provided data on all medical special reimbursement rights granted between 1966 and 2012. Follow-up started at the first operation and ended at death, date of emigration, or December 31, 2012. A total of 8623 patients met inclusion criteria. Follow-up was 99.9%. A total of 3750 patients (43%) required special reimbursements rights for a chronic disease. Cardiovascular disease was the most common late morbidity among patients (28%), followed by obstructive pulmonary disease (9%), neurologic disease (3%), and psychiatric disease (2%). Heart failure (simple hazard ratio [HR], 56.3 [95% CI, 35.4-89.7]; severe HR, 918.0 [95% CI, 228.9-3681.7]) and arrhythmia (simple HR, 11.0 [95% CI, 7.1-17.0]; severe HR, 248.0 [95% CI, 61.3-1002.7]) were the most common cardiovascular morbidities. Hypertension was common among patients with coarctation of the aorta (13%; incidence risk ratio [RR], 8.9; 95% CI, 7.5-10.7). Psychiatric disease was more common among simple defects, particularly ventricular septal defects. Conclusions Chronic cardiac and noncardiac sequelae are common after CHS regardless of the severity of the defect, underscoring the importance of long-term follow-up of all patients after CHS.

Effectiveness of the 10-valent pneumococcal conjugate vaccine among girls, boys, preterm and low-birth-weight infants - Results from a randomized, double-blind vaccine trial

BACKGROUND

Several studies have shown differences in susceptibility to infections and immune response to vaccines by sex. Prematurely born infants are at higher risk for pneumococcal diseases, with lower effectiveness for some vaccines compared to term infants. We have reported the effectiveness of the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV10) on several endpoints in the Finnish Invasive Pneumococcal disease (FinIP) vaccine trial. Now, we present the results of a post-hoc analysis evaluating PHiD-CV10 effectiveness in subgroups by sex, gestational age, and birth weight.

METHODS

The FinIP trial was a phase III/IV cluster-randomized, double-blind trial. Infants enrolled < 7 months of age received PHiD-CV10 in two thirds of clusters (3 + 1 or 2 + 1 schedule) and hepatitis B vaccine as control in remaining third. Outcome data included invasive pneumococcal disease, pneumonia, tympanostomy tube placements, and antimicrobial purchases collected through national, routinely used health registers. Negative binomial model was used in the incidence and vaccine effectiveness estimation, and differences in incidences between subgroups were tested among control children.

RESULTS

Of the 30,527 infants enrolled 51% were boys. The incidences of hospital-diagnosed pneumonia and otitis-related outcomes were higher among boys in control groups. There were no significant sex differences in the vaccine effectiveness estimates. Altogether, 1519 (5%) infants were born before 37th gestational week. The incidences of pneumonia outcomes were higher among premature infants when compared to term infants. The vaccine effectiveness estimates among preterm infants were not statistically significant except for antimicrobial purchases, but all point estimates were at the same level among preterm infants as among term infants. There was no significant difference between 2 + 1 and 3 + 1 schedules in any of the subgroups analysed.

CONCLUSION

PHiD-CV10 had a similar effectiveness in both sexes, and seemed to be protective in preterm infants.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00861380 and NCT00839254.

Vaccine-preventable disease incidence of pneumococcal conjugate vaccine in the Finnish invasive pneumococcal disease vaccine trial

Estimation of the full disease burden caused by Streptococcus pneumoniae is challenging due to the difficulties in assigning the aetiology especially in lower and upper respiratory infections. We estimated the pneumococcal disease burden by using the vaccine-preventable disease incidence (VPDI) of PHiD-CV10 vaccine (GSK) in our clinical trial setting. Finnish Invasive Pneumococcal disease (FinIP) trial was a cluster-randomized, double-blind trial in children <19 months who received PHiD-CV10 in 52 clusters or hepatitis B/A vaccine as control in 26 clusters according to 3+1 or 2+1 schedules (infants < 7 months) or catch-up schedules (children 7-18 months). Outcome data were collected using Finnish routine health-care registers, consisting of THL National Infectious Diseases Register, THL Care register, and Benefits Register of Social Insurance Institution of Finland. Blinded follow-up lasted from the date of first vaccination (trial enrolment Feb-2009 through Aug-2010) to January 31, 2012 for Invasive Pneumococcal Disease (IPD) and to end of December 2011 for four other outcomes: non-laboratory-confirmed IPD, hospital-diagnosed pneumonia, tympanostomy tube placements, and antimicrobial purchases. VPDI was estimated as difference in disease incidences between PHiD-CV10 clusters and control clusters. Altogether >47,000 children were enrolled. In 30,527 vaccinated infants <7 months at first dose, the VPDIs per 100,000 person-years were 75 for laboratory-confirmed IPD, 210 for non-laboratory-confirmed IPD, 271 for hospital-diagnosed pneumonia, 1143 for any tympanostomy tube placements and 11,381 for antimicrobial outpatient prescription, mainly due to otitis media. In a European developed-country setting, over 95% of the disease episode reductions in vaccinated children were seen in mild upper respiratory infections. The VPDIs of severe diseases are underestimated, because the majority of invasive disease goes undetected with routine blood-culture-based definitions. Evaluation of the absolute reduction achievable with vaccinations using sensitive case detection is essential for understanding the full disease burden, for valid cost-effectiveness analyses and for appropriate vaccination policy decisions. Registration: ClinicalTrials.gov, NCT00861380 and NCT00839254.

Vaccine effectiveness of the pneumococcal Haemophilus influenzae protein D conjugate vaccine (PHiD-CV10) against clinically suspected invasive pneumococcal disease: a cluster-randomised trial

BACKGROUND

Vaccine effectiveness of pneumococcal conjugate vaccines against culture-confirmed invasive pneumococcal disease has been well documented. In the Finnish Invasive Pneumococcal disease (FinIP) trial, we reported vaccine effectiveness and absolute rate reduction against laboratory-confirmed invasive pneumococcal disease (confirmation by culture or antigen or DNA detection irrespective of serotype). Here, we assessed vaccine effectiveness of PHiD-CV10 against clinically suspected invasive pneumococcal disease in children by use of diagnoses coded in hospital discharge registers.

METHODS

For this phase 3/4 cluster-randomised, double-blind trial, undertaken between Feb 18, 2009, and Dec 31, 2011, in municipal health-care centres and the Tampere University Vaccine Research Centre (Finland), we randomly assigned (2:2:1:1) 78 clusters into PHiD-CV10 three plus one, PHiD-CV10 two plus one, control three plus one, control two plus one groups (26:26:13:13 clusters) to give PHiD-CV10 in either three plus one or two plus one schedule (if enrolled before 7 months of age; infant schedules), two plus one (if enrolled between 7 and 11 months; catch-up schedules), and two doses at least 6 months apart (if enrolled between 12 and 18 months; catch-up schedules). Children were eligible if they had not received and were not anticipated to receive any of the study vaccines and had no general contraindications to vaccinations. We collected all inpatient and outpatient discharge notifications from the national hospital discharge register with International Classification of Diseases (ICD) 10 diagnoses compatible with invasive pneumococcal disease or unspecified sepsis, and verified data with patient files. We excluded invasive pneumococcal disease cases confirmed by positive culture or DNA/RNA detection from normally sterile body fluid. The primary objective was to estimate vaccine effectiveness against all register-based non-laboratory-confirmed invasive pneumococcal disease or unspecified sepsis and patient-file verified non-laboratory-confirmed invasive pneumococcal disease in infants younger than 7 months at enrolment. Masked follow-up lasted from the date of the first vaccination to Dec 31, 2011. Vaccine effectiveness was calculated against all episodes. This trial is registered with ClinicalTrials.gov, numbers NCT00861380 and NCT00839254.

FINDINGS

We enrolled 47,366 children. On the basis of ICD-10 diagnoses, we recorded 264 episodes of register-based non-laboratory-confirmed invasive pneumococcal disease or unspecified sepsis, of which 102 were patient-file verified non-laboratory-confirmed invasive pneumococcal disease. The vaccine effectiveness was 50% (95% CI 32-63) in the 30,527 infants with three plus one and two plus one schedules combined and the absolute incidence rate reduction was 207 episodes per 100,000 person-years (95% CI 127-286). The vaccine effectiveness against the patient-file verified non-laboratory-confirmed invasive pneumococcal disease was 71% (95% CI 52-83) in infant three plus one and two plus one schedules combined. The absolute rate reduction was 142 episodes per 100,000 person-years (95% CI 91-191) in infant cohorts.

INTERPRETATION

This vaccine-probe analysis is the first report showing the effect of pneumococcal conjugate vaccines on clinically suspected invasive pneumococcal disease. The absolute rate reduction was markedly higher compared with laboratory-confirmed invasive pneumococcal disease, which implies low sensitivity of the laboratory-based case definitions and subsequently higher public health effect of pneumococcal conjugate vaccines against invasive pneumococcal disease than previously estimated.

FUNDING

GlaxoSmithKline Biologicals SA and National Institute for Health and Welfare (THL), Finland.

Effectiveness of the ten-valent pneumococcal Haemophilus influenzae protein D conjugate vaccine (PHiD-CV10) against invasive pneumococcal disease: a cluster randomised trial

BACKGROUND

The Finnish Invasive Pneumococcal disease (FinIP) vaccine trial was designed to assess the effectiveness of a pneumococcal vaccine containing ten serotype-specific polysaccharides conjugated to Haemophilus influenzae protein D, tetanus toxoid, and diphtheria toxoid as the carrier proteins (PHiD-CV10) against invasive pneumococcal disease.

METHODS

In this cluster-randomised, double-blind trial, children aged younger than 19 months received PHiD-CV10 in 52 clusters or hepatitis vaccines as control in 26 clusters. Infants aged younger than 7 months at the first vaccination received either a 3+1 or a 2+1 vaccination schedule, children aged 7-11 months received a 2+1 schedule, and those 12-18 months of age received a two-dose schedule. The primary and secondary objectives were to assess vaccine effectiveness against culture-confirmed invasive pneumococcal disease due to any of the ten vaccine serotypes for the 3+1 and 2+1 schedules, respectively, in children who received at least one PHiD-CV10 dose before 7 months of age. Masked follow-up of pneumococcal disease lasted from the first vaccination (from February, 2009, to October, 2010) to January 31, 2012. Invasive disease data were retrieved from data accumulated in the national infectious diseases register. This trial and the nested acute otitis media trial are registered with ClinicalTrials.gov, numbers NCT00861380 and NCT00839254, respectively.

FINDINGS

47,369 children were enrolled from February, 2009, to October, 2010. 30,528 participants were assessed for the primary objective. 13 culture-confirmed vaccine-type cases of invasive pneumococcal disease were detected: none in the PHiD-CV10 3+1 group, one in the PHiD-CV10 2+1 group, and 12 in the control groups. The estimates for vaccine effectiveness were 100% (95% CI 83-100) for PHiD-CV10 3+1 and 92% (58-100) for PHiD-CV10 2+1 groups. Two cases of any culture-confirmed invasive disease irrespective of serotype were detected in combined PHiD-CV10 infant cohorts compared with 14 in the corresponding control cohorts (vaccine effectiveness 93%, 75-99). In catch-up cohorts, seven cases of invasive disease were reported, all in the control group: two cases in the children enrolled at 7-11 months of age; and five cases in children enrolled at 12-18 months of age (vaccine effectiveness 100%, 79-100). Non-fatal serious adverse events suspected to be vaccine-related were reported via routine post-immunisation safety surveillance in 18 children.

INTERPRETATION

This nationwide trial showed high PHiD-CV10 effectiveness against invasive pneumococcal disease when given in different schedules. For the first time, effectiveness of a 2+1 schedule in infants was confirmed in a clinical trial.

FUNDING

GlaxoSmithKline Biologicals SA and National Institute for Health and Welfare, Finland.

Demonstration of glaucomatous optic disc changes by electronic subtraction

We describe a new method, the electronic subtraction, for objective two-dimensional detection, demonstration and recording of glaucomatous optic disc changes. Siemens subtraction unit M 707 A, based on a double videochain and originally developed for the study of roentgenograms, was used. The results show that this technique is useful in demonstrating the progressive damage of neural tissue of the disc and associated alterations in the course of the vessels. Further development of the electronic subtraction method for glaucomatous optic disc evaluation is discussed.

Electronic subtraction method for ophthalmic photography

A commercial electronic subtraction unit originally intended for the study of roentgenograms was used to produce subtraction pictures of fundus fluorescein angiographies. No modifications were needed to make good quality subtraction pictures. The method is fast and inexpensive in contrast to previously described photographic methods. Certain limitations of the present equipment are discussed as well as some possibilities for further development of the apparatus. The method is especially suitable for studies on dynamic processes in the eye and it should prove valuable in the long-term follow-up of chronic diseases such as glaucoma and diabetic retinopathy.

[Single-ventricle heart defects--long-term prognosis, late complications and quality of life]

Treatment of a single-ventricle heart defect involves redirecting of systemic venous blood returning to the heart to gradually flow directly into the pulmonary artery without the functional right side of the heart being involved. In developed countries, three out of four persons with this ailment will nowadays reach adulthood. Among these, at least one out of four presents significant associated problems and late complications. The most significant problems include heart failure, arrhythmias, cyanosis and thromboembolic complications that increase over time. In addition to these, neurological complications have an influence on the quality of life in some patients.

Nosocomial infections after pediatric cardiac surgery

BACKGROUND

This study examined the rate of nosocomial infection (NI) in children who underwent cardiac surgery, and also investigated the impact of postdischarge infection surveillance. Risk factors for surgical site infections (SSIs) also were evaluated.

METHODS

All patients who underwent open-heart cardiac surgery in the Hospital for Children and Adolescents, Helsinki University Central Hospital, Finland, between January 2000 and December 2002 were included. Data were collected retrospectively from hospital registries. A prospective postdischarge survey was conducted to detect SSIs arising within 30 days after surgery, as well as respiratory and gastrointestinal infections with onset within 3 days after discharge.

RESULTS

The study included 614 procedures performed in 511 patients. A total of 80 NIs were found (overall NI rate, 6.3 per 1000 patient days), including 21 superficial and 6 deep SSIs. Multivariable analysis identified preoperative hospitalization > 48 hours and high American Society of Anesthesiologists (ASA) score as risk factors for SSI. The postdischarge study revealed 7 additional superficial SSIs, 29 respiratory infections, and 29 gastrointestinal infections; 12 patients required rehospitalization.

CONCLUSIONS

Almost 25% of the patients had at least 1 NI. All severe NIs were detected during the postoperative hospital stay. Respiratory and gastrointestinal infections were common and often led to rehospitalization, thus increasing costs.

Estimating intensity of physical activity: a comparison of wearable accelerometer and gyro sensors and 3 sensor locations

Automatic estimation of physical activity using wearable sensors can be used for promotion of a healthier lifestyle. In this study, accelerometers and gyroscopes attached to ankle, wrist and hip were used to estimate intensity of physical activity. The estimates are compared to metabolic equivalent (MET) obtained from a portable cardiopulmonary exercise testing system. Data from common everyday tasks and exercise were collected with 11 subjects. The tasks include, e.g., ironing, vacuuming, walking, running and cycling on exercise bicycle (ergometer). The strongest linear correlation with metabolic equivalent was obtained with the tri-axial accelerometer attached to the ankle (r=0.86).

Long-term results of pediatric cardiac surgery in Finland: education, employment, marital status, and parenthood

OBJECTIVE

This population-based study was designed to examine the psychosocial outcome of Finnish patients who had been operated on for congenital heart disease during childhood.

METHODS

A questionnaire was mailed to 3789 adult patients who had been operated on for congenital heart defects in Finland. Of these, 2896 (76%) answered the questionnaire. The mean age of patients was 33 years (range: 18-59 years), and they had had their first operation 9 to 46 years earlier.

RESULTS

The patients had coped well with their defects when compared with the general Finnish population. The educational level of patients was comparable to and employment level was higher than expected (70% vs 66%, respectively). They were living in a steady relationship as often as the general population, but the number of parents among the patients was lower than that expected (47% vs 49%, respectively). The incidence of congenital heart disease among the 2697 children of the patients was 2.4%.

CONCLUSION

Our results confirm that in addition to high survival rate, the long-term psychosocial outcome of patients with surgically treated congenital heart defects is good if they do not have any additional syndromes that cause mental retardation.

Airway pressure release ventilation and prone positioning in severe acute respiratory distress syndrome

BACKGROUND

Implementation of lung protective strategy in the treatment of severe Acute Respiratory Distress Syndrome (ARDS) has been reported to be associated with improved outcome. To fulfil this approach, sedation, neuromuscular blocking agents and full mechanical ventilatory support are often used in critical failure of gas exchange.

CASE REPORT

We present a patient who developed multiple organ failure, including severe ARDS, after severe skin injuries and septic shock. Ventilatory strategy consisted of lung protective approach, permissive hypercapnia and prone positioning. Airway pressure release ventilation (APRV) with the patient's superimposed spontaneous breathing was implemented and maintained, also during prone episodes. Improvement of gas exhange occurred after application of combined use of APRV and prone positioning.

CONCLUSION

APRV and maintenance of patients' spontaneous ventilation is feasible during prone positioning, and this approach may have beneficial synergistic effects on gas exhange in patients with severe acute lung injury.

Asymmetry of gait after free flap reconstruction of severe tibial fractures with extensive soft-tissue damage

Gait patterns of the preferred speed were investigated on 17 patients recovering (9 months-14 years) after reconstruction of severe tibial fractures. A novel data-acquisition system was used to record the plantar pressures as well as electromyographic (EMG) activities during walking. The results indicated incomplete recovery of symmetrical gait patterns. In particular, the duration of the stance phase was shorter on the operated side (mean (SD) 701 (90) ms compared with 765 (128) ms, p < 0.001). The peak pressure points under the foot were different on bilateral comparison, the operated side being regularly higher under the lateral forefoot area. This may imply attempts to reduce the loading of the ankle joint during stance. The pressure distribution models reflected these asymmetrical patterns more specifically than the EMG activities of the lower leg muscles examined.

Lens autofluorescence and light scatter in relation to the lens opacities classification system, LOCS III

PURPOSE

To compare values of the human lens autofluorescence and back light scatter measurements with the improved Lens Opacities Classification System, LOCS III.

METHODS

We measured autofluorescence and back light scatter of the lens from 122 smoking males aged 57 to 76 years who participated in a cancer prevention study. The retroillumination and slit-lamp photographs of the lenses were graded according to LOCS III by the Center for Ophthalmic Research in Boston. Lens fluorometry was carried out with a previously described technique using blue-green (495 nm/520 nm) autofluorescence range. Interzeag Lens Opacity Meter 701 was used for light scatter measurements.

RESULTS

LOCS III nuclear opalescence and color grades were statistically significantly correlated with lens autofluorescence as well as with light scatter values. The lens transmission index of autofluorescence measurements showed the highest correlation with the nuclear color (r = -0.71; p < 0.0001) and the light scatter value with nuclear opalescence (r = 0.64; p < 0.0001). There was no correlation between autofluorescence measurements and LOCS III grades of cortical or posterior subcapsular cataract. A weak relation could be found between the grades of cortical cataract and light scatter values.

CONCLUSIONS

The lens fluorometry provides a practical clinical technique to evaluate the yellow coloration and opalescence of the human lens nucleus. It may be a useful additional tool together with a subjective grading system in the follow-up of optical changes occurring in the nuclear region of the lens.

[Grief among the psychiatric outcare-patients]

The aim of the study is to describe the features of bereavement and the life situation among the bereaved psychiatric outcare-patients. The impact of social support on stress and adaption has been indicated in previous studies. Social support of the patients belongs to the nursing care. The possibilities of the family-centered nursing to support the relatives in bereavement will also be discussed. The sample consisted of new patients' in psychiatric outcare (N = 32). The ground of the need to the care was the dead of their relative. The information has been gathered of the care records and it has been analysed by the content analysis. Following contents have been described: The features of the bereavement and the relations to the relatives. The features of the bereavement consisted of following categories depressive behavior, anxiety, hate and fear, self-destructive behavior and feelings of guilt. Relations to the other relatives consisted of following categories: Rejected by the relatives and disappointed in the relationship. The results indicated, that the patients did not receive social support in their daily life. The family-centered nursing will allow the social support also to the relatives after the dead of the patient.

Free flap reconstructions of 100 tibial fractures

OBJECTIVE

Reconstructive microsurgery has been part of the treatment for severe tibial fractures for over 20 years.

METHODS

In this study, we have analyzed 100 patients with 104 microvascular reconstructions to the lower leg in a 15-year period (1980-1994). Sixty-three of the reconstructions were made during the past 5 years (1990-1994), which means that microvascular reconstruction is increasing as a treatment of severe tibial fractures.

RESULTS

Free flap transfer is a safe procedure: the failure rate among the patients studied was 2%, and the amputation rate was 5%.

CONCLUSION

In the past 5 years, the flap survival rate and the microvascular free flap operation methods were the same as they were in the 1980s, but the methods for enhancing the fracture union or reconstructing the bone defect has changed.

[Quantitative and qualitative nursing research]

The aim of this article is to open a discussion on Nursing research methods. Authors give some thoughts on qualitative nursing research and underlining the difference between positivistic and teleological vision. Relationship between inductive and deductive thinking is discussed.

Influence of lens autofluorescence on retinal nerve fiber layer evaluation

BACKGROUND

Yellow-brown coloration of the human lens increases with age and is associated with increasing lens autofluorescence. This may interfere with retinal image through scatter and absorption.

PATIENTS AND METHODS

We measured the lens autofluorescence (AF) of 30 eyes of 30 healthy subjects and evaluated their retinal nerve fiber layer (RNFL) visibility from fundus photographs. These otherwise healthy eyes showed a varying degree of yellow-brown coloration of the lens. Lens fluorometry was carried out with a previously described technique using blue-green AF range (495 nm/520 nm). RNFL photographs were taken with a Canon CF-60 ZA wide angle camera with blue (495 nm) interference filter and low-sensitivity, high resolution black-and-white film.

RESULTS AND CONCLUSION

Lens yellowing expressed here by means of lens autofluorescence measurements, was statistically significantly (r = -0.53, p = 0.0008) correlated with the RNFL visibility score. In stepwise regression analysis adding age to the model including only the maximum AF did not reduce the residual standard deviation statistically significantly (p = 0.1). This suggests that lens yellowing has an effect on RNFL visibility and may be an important confounding factor in clinical RNFL evaluation.

Fluorometry of the crystalline lens for correcting blue-on-yellow perimetry results

PURPOSE

Optical and neural sources of short wavelength sensitivity should be separated in the assessment of the results of blue-on-yellow (B/Y) perimetry. It has been shown previously that lens autofluorescence is related directly to lens yellowing and age. The aim of this study was to find out if B/Y perimetry results can be better corrected by using lens fluorometry than by age.

METHODS

The authors evaluated one randomly chosen eye of 40 normal subjects and 39 age-matched patients with ocular hypertension and different stages of glaucoma. The authors obtained the mean sensitivity (MS) of the 24-2 B/Y visual fields with a Humphrey perimeter and determined the lens transmission index (LTI) from the ratio between posterior and anterior autofluorescence peaks measured with their fluorometer. A multiple regression analysis was used to evaluate the variability of the B/Y MS by age and LTI in normal subjects.

RESULTS

The authors found a statistically highly significant linear correlation of B/Y MS to LTI in healthy subjects (R = 0.83; P < 0.0001). The 95% prediction interval of the normal subjects was determined. The majority of the MS values of the ocular hypertensives were inside the prediction limits, whereas approximately half of the patients (4 of 9) with early glaucoma and the majority of patients (14 of 15) with moderate and advanced glaucoma were below the prediction interval. The residual standard deviation of the B/Y MS with age alone was larger than that with LTI alone in the model (3.66 dB and 3.22 dB, respectively).

CONCLUSIONS

The interindividual variation of the lens transmission properties increases with age. The reference level for correcting B/Y perimetry results can be determined more precisely using fluorometry of the lens than with age alone.

A static shoulder model based on a time-dependent criterion for load sharing between synergistic muscles

A static shoulder model including a novel muscular synergy principle for computing load sharing between the shoulder muscles is presented. This principle is feasible especially when analysing endurance-type activities. According to the principle, time elapsed from the start of the activity decreases the allowable muscle stress levels on the basis of the stress-endurance time curves of individual muscles. At low load levels the sum of the squared forces is minimized. At higher load levels the increase in the stress levels of individual muscles is counteracted in order to prevent fatigue. In the model the direction of the contact force in the glenohumeral joint is constrained. The stiffness of the shoulder can also be constrained to produce more muscular co-contraction in tasks with high precision demands.

Evidence of deterministic chaos in the myoelectric signal

Our aim was to study whether the myoelectric signals can be better modelled as outputs of a nonlinear dynamic system rather than as random stochastic signals. Both the nonlinear predictability and the dimensionality of the signals were studied using methods of nonlinear dynamics. The signals were measured from the biceps brachii muscle during both fatiguing and non-fatiguing isometric contractions at low load levels. The myoelectric signals were found to be nonlinear and to have a structure statistically distinguishable from random noise. The correlation dimension describing the dimensionality of the myoelectric signal decreased during local muscular fatigue. The results support the use of the theory of nonlinear dynamics for the modelling of the myoelectric signals.

Muscular synergy in the shoulder during a fatiguing static contraction

The synergic operation of shoulder muscles during a fatiguing submaximal arm flexion task was studied using both a biomechanical 3-dimensional shoulder model and electromyographic recordings. A new optimization scheme aiming to maximize the task endurance time by constantly regulating the force output of each muscle is utilized in the model. The method can be used to simulate the muscle rotation phenomenon, which has been proposed to occur during an endurance type contraction. The model predictions on the fatigue order of the shoulder muscles were compared to results derived using the median frequencies of the electromyographic signals from nine muscles or muscle parts. In the test performed 10 men held until exhaustion a weight (4 kg) suspended on the wrist with the arm in horizontal flexion. The deltoid, infraspinatus, and supraspinatus muscles were the first to show electromyographic signs of fatigue. The times for detecting electromyographic changes in the trapezius muscle were longer than those in the muscles first showing electromyographic signs of fatigue. The biomechanical model used predicted the upper and lower infraspinatus and the anterior part of the deltoid to be the first to show signs of fatigue during the flexion task. The predictions of the biomechanical model on the order of fatigue of the nine shoulder muscles monitored also using electromyographic recordings corresponded to the electromyographic results. However, the accuracy of this comparison is limited by the fact that the electromyographic recordings did not cover all the muscles used in the model. No clear order was found for the development of electromyographic signs of muscle fatigue. RELEVANCE--:The biomechanical model and the developed optimization methods provide new tools for studying the synergic operation of shoulder muscles during fatiguing contractions. Our results will help in analysing and optimizing shoulder load in problematic functions both of work and leisure activities.

Quantification of the static load component in muscle work using nonlinear filtering of surface EMG

Prolonged static strain on the muscles of the neck-shoulder region is believed to be linked to the development of musculoskeletal problems. To quantify the static strain on the basis of EMG, the level as well as the duration of the muscle load should be analysed on temporal basis. In this paper, some methods for the temporal analysis of EMG recordings are proposed with an aim of quantifying the long-term static strain on the muscle. The use of nonlinear median prefilters for decomposing the EMG activity according both to amplitude level and duration of the activity at different levels is proposed. The prefiltering methods were also evaluated using laboratory studies. The main aim of the studies was to compare the estimation errors between EMG and force for different types of prefilters especially when the static load component was analysed. The average estimation error for sequences having a duration longer than 1 s was found to be 8% of MVC in the case of trapezius muscle and 14% of MVC in the case of biceps brachii muscle. Linear relation was found on the basis of linear least squares curve fitting to give the largest correlation coefficients between EMG and force, when the static load component was analysed.

Load-sharing patterns in the shoulder during isometric flexion tasks

Patterns of load-sharing between the shoulder muscles during isometric flexion tasks were studied by using both a biomechanical shoulder model and electromyographic (EMG) recordings of ten subjects. The effect of changes in several model parameters and shoulder stiffness constraints on the predicted load-sharing patterns were studied, while the arm position, hand load and precision requirements of the tasks were varied. The results calculated using the model were, when compared to the EMG recordings, plausible predicting a high level of synergistic contraction of muscles of the shoulder muscles during flexion tasks. The trends of the model-predicted muscle forces corresponded well to the EMG recordings. At low hand load levels the increasing of the shoulder stiffness strongly increased the muscle force levels, thus increasing also the level of synergistic contraction of muscles. At higher load levels the increase in the muscle forces was not so high, because the model predicted a high level of simultaneous contraction of muscles already at a low level of shoulder stiffness. Cluster analysis of the EMG recordings revealed large inter-individual differences in the load distribution patterns during flexion tasks. The constraint angle of the glenohumeral joint contact force direction was found to be an important model parameter affecting both the predicted forces and the maximum force production ability of the shoulder.

Free flap reconstructions of tibial fractures complicated after internal fixation

The cases of 15 patients are presented where microvascular soft-tissue reconstructions became necessary after internal fixation of tibial fractures. Primarily, seven of the fractures were closed. Eleven fractures had originally been treated by open reduction and internal fixation using plates and screws, and four by intramedullary nailing. All of the patients suffered from postoperative complications leading to exposure of the bone or fixation material. The internal fixation material was removed and radical revision of dead and infected tissue was carried out in all cases. Soft tissue reconstruction was performed using a free microvascular muscle flap (11 latissimus dorsi, three rectus abdominis, and one gracilis). In eight cases the nonunion of the fracture indicated external fixation. The microvascular reconstruction was successful in all 15 patients. In one case the recurrence of deep infection finally indicated a below-knee amputation. In another case, chronic infection with fistulation recurred postoperatively. After a mean follow-up of 26 months the soft tissue coverage was good in all the remaining 13 cases. All the fractures united. Microvascular free muscle flap reconstruction of the leg is regarded as a reliable method for salvaging legs with large soft-tissue defects or defects in the distal leg. If after internal fixation of the tibial fracture the osteosynthesis material or fracture is exposed, reconstruction of the soft-tissue can successfully be performed by free flap transfer. By radical revision, external fixation, bone grafting, and a free flap the healing of the fracture can be achieved.

Autofluorescence in cataractous human lens and its relationship to light scatter

The autofluorescence profile of the lens was measured from 84 eyes of 84 patients with cortical, nuclear, posterior subcapsular, or mixed lens opacities. Measurements were performed with a fluorometer in the blue-green autofluorescence range (495 nm/520 nm). The mean maximum autofluorescence value differed in every cataract group statistically significantly from that of the age matched controls (p < or = 0.0058). The highest autofluorescence values were measured in nuclear and mixed cataract groups (p < 0.0001) with high and narrow autofluorescence profile. In cortical cataracts the curve was low and flattened and the mean maximum autofluorescence value was lower than in the control eyes (p < 0.0001). The maximum autofluorescence was related to lens coloration as well as to visual acuity only in nuclear cataract. The regression between maximum autofluorescence and light scatter was statistically significant only in the nuclear cataract group (p = 0.0004). Since the autofluorescence profiles differed not only in height but also in width between the cataract groups, various width/maximum autofluorescence ratios were measured. In nuclear and mixed cataract groups the ratio 75% width/maximum autofluorescence was statistically significantly lower than in other groups (p < 0.0001). In cortical cataracts the ratio (50% width - 75% width)/maximum autofluorescence was statistically significantly higher than in other groups (p < 0.0001).

Normalization of electromyogram in the neck-shoulder region

Linear and curvilinear electromyogram (EMG) normalization methods were compared among ten healthy men during a simulated work cycle demanding attention and static holding of the arm ('Solitaire test'). Maximal voluntary contractions (MVC) and gradually increasing contractions up to 70% of MVC were used for normalization in different arm postures. The test contractions studied included inward and outward rotations, abduction, shoulder elevation, and flexion in different arm positions. The shoulder load moment was calculated for the flexion tests using a simple two-dimensional model. The effect of arm posture on the EMG versus shoulder load moment relationship was studied on the following muscles: supraspinatus, infraspinatus, trapezius (three parts), deltoid (two parts) and pectoralis major. All muscles participated in the MVC tests performed, and its was not possible to suggest a single recommended test for each muscle. Differences in normalized EMG median values ranging up to 30% of MVC were found between linear and curvilinear normalization methods. Short-term repeatability of normalization based on a contraction with gradually increasing force was good. Arm posture affected the relationships between shoulder load moment and EMG activity of all muscles studied. Arm posture did not, however, have a significant effect on the estimated amplitude probability distribution functions during the simulated work task. Therefore, at least for the tasks studied, the principle of normalizing in the middle position of the range of movement was deemed acceptable.