Rotavirus vaccination coverage and adherence to recommended age among infants in Flanders (Belgium) in 2012

In Belgium, rotavirus vaccination has been recommended and partially reimbursed since October 2006. Through a retrospective survey in 2012, we estimated the coverage rate of the rotavirus vaccination in Flanders among infants born in 2010. Using a standardised questionnaire, 874 families were interviewed at home, collecting information on demographic characteristics, socio-economic background and documented vaccination history (updated from medical files and vaccination database, if needed). Adherence to the recommended age for vaccination (8, 12 and 16 weeks) was also assessed. The coverage rate for two doses of rotavirus vaccination was 92.2% (95% confidence interval: 90.2-93.8). Respectively 31.7% and 10.1% of the children received their first and second dose at the recommended age. Incomplete vaccination was often a deliberate choice of the parents. Only eight children (1%) were vaccinated after the maximum age of 26 weeks. Factors identified by multiple logistic regression as related to incomplete vaccination were: living in the province of Antwerp, unemployed mother, and three or more older siblings in the household. Four years after introduction, the coverage rates were surprisingly high for a vaccine that is not fully reimbursed and not readily available in the vaccinator's fridge, which is the case for the other recommended infant vaccines.

Prevalence of endometriosis diagnosed by laparoscopy in adolescents with dysmenorrhea or chronic pelvic pain: a systematic review

BACKGROUND Endometriosis associated with pain symptoms in adolescents has been extensively reported, but the exact prevalence is unclear because pain symptoms may be atypical and endometriosis can only be diagnosed by laparoscopy. The aim of this paper is to provide a systematic review of the prevalence of endometriosis diagnosed by laparoscopy in adolescents. METHODS A systematic literature search was carried out for relevant articles published between 1980 and 2011 in the databases PUBMED and EMBASE, based on the keywords 'endometriosis', 'laparoscopy', 'adolescents' and 'chronic pelvic pain (CPP)'. In addition, the reference lists of the selected articles were examined. RESULTS Based on 15 selected studies, the overall prevalence of visually confirmed endometriosis was 62% (543/880; range 25-100%) in all adolescent girls undergoing laparoscopic investigation, 75% (237/314) in girls with CPP resistant to treatment, 70% (102/146) in girls with dysmenorrhea and 49% (204/420) in girls with CPP that is not necessarily resistant to treatment. Among the adolescent girls with endometriosis, the overall prevalence of American Society of Reproductive Medicine classified moderate-severe endometriosis was 32% (82/259) in all girls, 16% (17/108) in girls with CPP resistant to treatment, 29% (21/74) in girls with dysmenorrhea and 57% (44/77) in girls with CPP that is not necessarily resistant to treatment. Due to the quality of the included papers an overestimation of the prevalence and/or severity of endometriosis is possible. CONCLUSIONS About two-thirds of adolescent girls with CPP or dysmenorrhea have laparoscopic evidence of endometriosis. About one-third of these adolescents with endometriosis have moderate-severe disease. The value of early detection of endometriosis in symptomatic adolescents and the indications for laparoscopic investigation in adolescents require more research.

Measuring determinants of oral health behaviour in parents of preschool children

OBJECTIVE

The aim of this study was to develop a valid and reliable measure for oral health behaviour and its determinants in five-year-old Flemish children, based on the Theory of Planned Behaviour (TPB) and to test its predictive validity.

METHODS

1157 parents of five-year-olds completed a questionnaire measuring three behaviours related to oral health among children (dietary habits, oral hygiene, dental attendance) and their determinants (attitude, subjective norms, perceived behavioural control, intention). The sample was randomly split in two halves and principal component analyses were performed on one half sample to identify the factor structure. Confirmatory factor analyses were performed on the remaining half sample to obtain a cross-validation. Predictive validity was tested using multiple regression analyses.

RESULTS

For each behaviour four component structures reflecting the TPB-dimensions, accounting for 44% to 55% of the variance were retrieved and confirmed in the cross-validation. Internal consistency (Cronbach's alpha) of the scales ranged from 0.52 to 0.80. A sizeable percentage of variance of intentions and behaviours was explained by the model.

CONCLUSIONS

The TPB components were significant predictors of intentions and behaviours. These findings argue for the reliability and validity of the questionnaire for exploring determinants underlying parental oral health behaviour.

Oral health and oral health-related behaviour in preschool children: evidence for a social gradient

This study aims to investigate the social gradient in the reported oral health-related behaviour and oral health status of preschool children. Participants were 1,057 children born between October 2003 and July 2004 in Flanders, Belgium. Oral health examinations were performed by trained dentists when the children were 3 and 5 years old (respectively, in 2007 and 2009); data on dietary habits, oral hygiene habits and dental attendance of the children were obtained through structured questionnaires completed by the parents. Maternal educational level, measured in four categories, was used as a proxy of socio-economic status. Logistic and ordinal regressions showed a social gradient for the oral health-related behaviours: a lower educational level of the mother was related to a higher consumption of sugared drinks between meals and to a lower brushing frequency and dental attendance of the child. Children from low-educated mothers also had seven times more chance to present with caries experience than children from mothers with a bachelor degree. Contrary to the expectations, there was a deviation from the gradient in 3-year-olds from the highest educational group showing an increased risk for caries experience (OR = 3.84, 95 % CI = 1.08-13.65). Conclusion. Already in very young children, a graded relationship is observed between socio-economic position, oral health and related behaviours. The results suggest that different approaches are required to promote oral health during early childhood depending on the mother's educational background. As children from the highest social group also have an increased caries risk, specific techniques may be needed.

Growth of Belgian and Norwegian children compared to the WHO growth standards: prevalence below -2 and above +2 SD and the effect of breastfeeding

BACKGROUND

New national growth references have been published in Belgium and Norway. The WHO recommends universal use of their 2006 Child Growth Standards based on data from breastfed children.

OBJECTIVE

To compare the growth of Belgian and Norwegian children with the WHO standards.

PARTICIPANTS

6985 children 0-5 years of age from Belgium and Norway.

DESIGN

Proportion of children below -2 SD and above +2 SD of the WHO standards was calculated for length/height, weight, body mass index and head circumference. Average SD scores of exclusively breastfed children of non-smoking mothers were compared with national reference data and with the WHO standards.

RESULTS

Generally, the number of Belgian and Norwegian children below -2 SD lines of the WHO standards was lower and above +2 SD higher than expected. The largest differences were for head circumference (0.97% Belgian and 0.18% Norwegian children below -2 SD, 6.55% Belgian and 6.40% Norwegian children above +2 SD) and the smallest for length/height (1.25% Belgian and 1.43% Norwegian children below -2 SD, 3.47% Belgian and 2.81% Norwegian children above +2 SD). The growth pattern of breastfed children of non-smoking mothers was in both countries more alike the local national growth references than the WHO standards.

CONCLUSIONS

There are significant deviations in the proportion of children outside normal limits (±2 SD) of the WHO standards. This was true for all children, including those who were exclusively breastfed. Hence, adoption of the WHO growth charts could have consequences for clinical decision-making. These findings advocate the use of national references in Belgium and Norway, also for breastfed children.

Parental smoking behavior and caries experience in preschool children

OBJECTIVES

The study aimed to explore the association between parental smoking behavior and caries experience in young children, taking into account the socioeconomic status and oral health-related behavior.

METHODS

Cross-sectional data from 1250 3-year-old and 1283 5-year-old children from four geographical areas in Flanders (Belgium) were analyzed. Children were examined at school by trained dentist-examiners, using standard criteria and calibrated examination methodology. Data on oral hygiene and dietary habits, oral health behavior, sociodemographic variables, and parental smoking behavior were obtained through structured questionnaires, completed by the parents.

RESULTS

Visible caries experience (i.e. d(3)mft > 0) was seen in 7% of 3-year olds and 31% of 5-year olds. In both age groups, 30% of the parents reported smoking behavior. Univariable logistic regression analysis with caries prevalence as the dependent variable, revealed that parental smoking was a significant independent variable. After controlling for age, gender, sociodemographic characteristics, oral hygiene, and dietary habits, the effect of family smoking status was no longer significant in 3-year-old children (OR = 1.98; 95% CI: 0.68-5.76). In 5-year olds the significant relationship between parental smoking behavior and caries experience persisted after adjusting for the other evaluated variables (OR = 3.36; 95% CI: 1.49-7.58).

CONCLUSION

The results of this study illustrate the existence of a significant association between parental smoking behavior and caries experience in 5-year-old children.

Measuring oral health behaviour in Flemish health care workers: an application of the theory of planned behaviour

OBJECTIVE

This study describes the development and validation of a questionnaire to measure the determinants of oral health related behaviour in health care workers, based on the Theory of Planned Behaviour (TPB).

RESEARCH DESIGN

A preliminary questionnaire was drafted containing 78 self report items measuring three behaviours related to oral health (i.e. dietary habits, oral hygiene habits and dental attendance), as well as the attitudes, perceived social norms and self-efficacy for each behaviour. The questionnaire was completed by 201 health care workers for the initial validation and 966 other health care workers for a replication.

OUTCOMES

A principal component analysis with Procrustes rotation toward an a priori three component structure on the original sample yielded high congruence measures for reported dental attendance, but not for dietary habits and oral hygiene habits. Subsequent exploratory Varimax rotations and discarding of redundant items resulted in three component solutions explaining 43% of the variance in dietary habits, 57% in oral hygiene habits and 66% in dental attendance, respectively. For all three behaviours, these components corresponded to the dimensions of the TPB. Internal consistency of the scales was satisfactory, with Chronbach's alpha's ranging from 0.51 to 0.87. Scale scores accounted for a significant proportion of the variance in the intention to avoid sweet snacks, to brush teeth, and to attend dental check-ups, and of the frequency of consumption of sweet drinks and frequency of brushing. A confirmatory factor analysis on the larger sample of 966 health care workers provided excellent goodness of fit indices, confirming the construct validity of the scales.

Administration of hepatitis A vaccine at 6 and 12 months of age concomitantly with hexavalent (DTaP-IPV-PRP approximately T-HBs) combination vaccine

BACKGROUND

Administration of two doses of hepatitis A (HA) vaccine to children > or = 2 years of age has been shown to be protective. The present study assessed whether HA vaccine can be administered as early as 6 months of age and whether it can be administered concomitantly with a hexavalent (HV) vaccine at this age.

METHODS

In an open label, randomized, parallel group study, the liquid HV vaccine (HEXAVAC) (diphtheria, tetanus, 2-component acellular pertussis, inactivated poliomyelitis vaccine, Haemophilus influenzae type b conjugated to tetanus protein and hepatitis B) was administered at 2, 4, 6, and 12 months of age to all children. HA vaccine (VAQTA) was given at 7 and 13 months in the separate administration group (Group 1) and at 6 and 12 months in the concomitant administration group (Group 2). Serum samples were obtained at 2, 7, 12, and 14 months in Group 1 and at 2, 7, 12, and 13 months in Group 2. The primary immunogenicity outcomes were the seroconversion rates for HA 1 month after the second dose of HA vaccine in initially seronegative subjects, and the seroconversion rates for each HV antigen 1 month after the third dose of the HV vaccine (both at 7 months of age).

RESULTS

HA seropositivity rates 1 month after the second dose were 100% in both groups, regardless of initial serostatus. The responses to each HV antigen 1 month after the third dose were similar in both groups. The vaccines were generally well tolerated in both groups regardless of vaccine(s) administered.

CONCLUSIONS

A schedule of two doses of HA vaccine, 6 months apart beginning at 6 months of age is highly immunogenic and well tolerated when administered alone or concomitantly with HV vaccine at 6 and 12 months of age.

Effects of lowering the aluminium content of a dTpa vaccine on its immunogenicity and reactogenicity when given as a booster to adolescents

As aluminium in vaccines has been associated with the incidence of local side effects occurring after vaccination, this observer-blind randomised clinical trial was designed to evaluate the effect of lowering the aluminium content of a combined reduced-antigen-content dTpa vaccine on immunogenicity and safety when administered to healthy adolescents aged 10-18 years. A total of 647 subjects were enrolled, 224 (35%) received a dTpa formulation with 0.5 mg aluminium, 209 (32%) a formulation with 0.3 mg aluminium and 214 (33%) a formulation with 0.133 mg aluminium. One month after boostering, all subjects were seroprotected against diphtheria and tetanus toxoids. All subjects were seropositive for anti-FHA and anti-PRN but 4% of the initially seronegatives in both reduced aluminium groups did not seroconvert for anti-PT. Booster responses did not differ significantly between groups for any antibody, but post booster vaccination anti-PT GMC's differed significantly between groups and decreased when vaccine aluminium content decreased. No clear difference between study groups in local or general side effects was demonstrated. The most frequently reported symptoms after vaccination were injection site pain (89.5-90.7%), fatigue (42.1-47.4%) and headache (41.1-45.1%). This study showed that the aluminium content has a specific influence on the immunogenicity of this dTpa vaccine.

CUGE: A SCREENING INSTRUMENT FOR ALCOHOL ABUSE AND DEPENDENCE IN STUDENTS

OBJECTIVES

The prevalence of alcohol abuse on college campuses ranges from 7 to 17%. Frequent heavy drinkers place themselves and others at risk for a variety of adverse consequences and frequently remain undetected. Brief individual interventions result in a significant reduction on the number of drinks. Therefore, detection of students at risk is useful and desirable. The CUGE has been elsewhere described as a promising screening device for problem drinking in students. In order to determine the diagnostic value of this new questionnaire, we set up a validation study in a new and independent population of freshmen.

METHODS

A cross-sectional diagnostic study. Participants were college freshmen of the Katholieke Universiteit Leuven. All students received a questionnaire, containing the CUGE, being the test of interest, and the CIDI as the reference test.

RESULTS

The CUGE combines a very high sensitivity of 91% with a reasonable specificity of 76.3% in this validation group.

CONCLUSIONS

The CUGE is an excellent screening device in this population of students. In addition, it is a short questionnaire with only yes or no questions. This makes the CUGE easily applicable as a part of broad routine questionnaires.

Renal function, cytogenetic measurements, and sexual development in adolescents in relation to environmental pollutants: a feasibility study of biomarkers

BACKGROUND

Human exposure to chemicals is normally monitored by measurement of environmental pollutants in external media. We investigated whether biomarkers in adolescents can show exposure to, and health effects of, common environmental pollutants.

METHODS

We recruited 200 17-year-old adolescents (120 girls) from a rural control area and from two suburbs polluted by a lead smelter and two waste incinerators. We measured biomarkers of exposure and of effect in blood and urine samples, and obtained questionnaire data. School doctors measured testicular volume and staged sexual maturation.

FINDINGS

Internal exposure was mostly within current standards. Concentrations of lead and cadmium in blood, PCBs (polychlorinated biphenyls) and dioxin-like compounds in serum samples, and metabolites of VOCs (volatile organic compounds) in urine were higher in one or both suburbs than in the control area. Children who lived near the waste incinerators matured sexually at an older age than others, and testicular volume was smaller in boys from the suburbs than in controls. Biomarkers of glomerular or tubular renal dysfunction in individuals were positively correlated with blood lead. Biomarkers of DNA damage were positively correlated with urinary metabolites of PAHs (polycyclic aromatic hydrocarbons) and VOCs. Interpretation Biomarkers can be used to detect environmental exposure to pollutants and measure their biological effects before overt disease develops. Our findings suggest that current environmental standards are insufficient to avoid measurable biological effects.

The effect of reconstitution of an Haemophilus influenzae type b-tentanus toxoid conjugate (PRP-T) vaccine on the immune responses to a diphtheria-tetanus-whole cell pertussis (DTwP) vaccine: a five-year follow-up

Controversial results have been obtained from previous studies on the combined administration of Haemophilus influenzae type b-tetanus toxoid conjugate (PRP-T) and diphtheria-tetanus-whole-cell pertussis (DTwP) combination vaccines, with regard to possible reciprocal interference between the constituent antigens. To document the priming effect and possible long-term immunogenic interference of PRP-T and DTwP combination vaccines, a randomized, double-blind, controlled study was conducted in Belgium. A total of 168 healthy infants received, at 3, 4 and 5 months of age, DTwP vaccine mixed just prior to injection either with PRP-T vaccine (group A, DTwP//PRP-T, N = 85) or with placebo (group B, DTwP//Placebo, N = 83). At the age of 14 months, children of both groups were randomized to receive either a dose of DTwP//PRP-T vaccine (subgroups A1 and B1) or a dose of Hib polysaccharide (PRP) vaccine (subgroups A2 and B2). Those children in subgroups A1 and B1 had an additional serum sample taken at the age of 5 years (at the time of a DT booster). The immune response to Hib polysaccharide at the age of 4, 5 and 6 months confirmed the excellent immunogenicity profile of PRP-T in infants. In addition, the vigorous anamnestic response (i.e. a 20-fold increase of GMT) to a booster dose of the plain capsular polysaccharide (PRP) reflected the efficient Hib-priming induced by the combined DTwP//PRP-T vaccine. Reconstitution of PRP-T with DTwP did not affect the immune response to diphtheria toxoid or pertussis agglutinins. Nevertheless, at almost any time point during the five-year follow-up, the tetanus antitoxin GMT values were significantly lower in the DTwP//PRP-T group (A and A1) than in the DTwP//Placebo group (B and B1). Despite the suppressive effect on GMT values, intergroup differences in rates of seroprotection were never significant, except after doses 2 and 3 for which there were lower percentages of children in group A with antitoxin titers > 0.05 IU/mL and > 1.0 IU/mL. In the group primed with the combined DTwP//PRP-T vaccine, (1) a DT booster dose at the age of 5 years provoked a 150-fold increase in tetanus antitoxin GMT, (2) a high tetanus antitoxin GMT value was attained (GMT = 19.3 IU/mL) and (3) all children in this group had tetanus antitoxin titers > 1.0 IU/mL, so it may be concluded that all these children will still be protected against tetanus until at least the age of the next recommended booster dose (i.e. the age of 15 years). No differences in the occurrence of adverse events were observed between the groups who received the DTwP//PRP-T vaccine or the DTwP//Placebo vaccine, both vaccines being associated with events customarily attributable to DTwP (data not shown). Our results indicate (1) that the combination vaccine, DTwP//PRP-T, represents a safe and effective alternative for the existing uncombined vaccines and (2) that the long-term effect of interference between the components of future combination vaccines should be studied with subsequent booster doses, followed by the evaluation of persistence of antibodies over several years.

Priming effect, immunogenicity and safety of an Haemophilus influenzae type b-tetanus toxoid conjugate (PRP-T) and diphtheria-tetanus-acellular pertussis (DTaP) combination vaccine administered to infants in Belgium and Turkey

To evaluate the priming effect, immunogenicity and safety of an Haemophilus influenzae type b (Hib) tetanus toxoid conjugate (PRP-T) and diphtheria-tetanus-acellular (two component) pertussis (DTaP) combination vaccine, a randomized, comparative study was conducted in two centers, one in Belgium and one in Turkey. A total of 410 healthy infants, 160 in Belgium and 250 in Turkey, randomly received DTaP and PRP-T vaccines in one of three fashions. One group (N = 138) received DTaP and PRP-T vaccines reconstituted immediately prior to injection at 3, 4 and 5 months of age, and are referred to as the combined, short schedule group (Co-S). A second group (N = 135) received DTaP + PRP-T simultaneously but injected at different sites according to the same schedule, and are referred to as the associated, short schedule group (As-S). The third group (N = 137) also received DTaP + PRP-T at separate sites, but at 2, 4 and 6 months, and are referred to as the associated, long schedule group (As-L). The As-L group allowed for serological bridging with a Senegalese two-component pertussis vaccine efficacy trial, using the same batch of DTaP vaccine. Children of both short-schedule groups (Co-S and As-S) received, at the age of 12-14 months, a booster dose of DTaP vaccine associated with unconjugated PRP vaccine. Mixing of the vaccines did not affect the immune response to the antigens included in the DTaP vaccine. The immune response to Hib capsular polysaccharide, however, was significantly lower after combined administration (Co-S group) than after associated (As-S group) administration (P < 0.0001), with a similar trend among both countries (GMTs, 1.78 microg/ml and 6.19 microg/ml in Belgium, and 5.02 microg/ml and 11.67 microg/ml in Turkey). Booster vaccination with the unconjugated PRP induced a vigorous and similar anamnestic response in both groups. Belgian infants showed a significantly lower immune response to all antigens than Turkish infants (P < or = 0.001 for all antigens), with a similar trend among each study group. In all groups, the incidence of adverse events was lower than that usually reported after DTwP(whole-cell) vaccine. Higher rates of systemic reactions were observed in the Belgian population, possibly due to differences in reporting practice. Our results indicate (1) that the combination vaccine, DTaP//PRP-T, represents an important improvement over the existing uncombined vaccines; (2) that immunogenicity studies should include at least one booster injection to evaluate priming effects by combined vaccines; and (3) that it is feasible and valuable to co-randomize combination vaccine studies in sufficiently different geographical areas and child populations.

Safety and immunogenicity of an Haemophilus influenzae type b-tetanus toxoid conjugate (PRP-T) and diphtheria-tetanus-pertussis (DTP) combination vaccine administered in a dual-chamber syringe to infants in Belgium and Chile

To document any unexpected differences in the immune response between study populations and to evaluate immunogenicity and safety of a simplified presentation (dual-chamber syringe) of an Haemophilus influenzae type b-tetanus toxoid conjugate (PRP-T) and diphtheria-tetanus-pertussis (DTP) combination vaccine, a multicentre, randomized, comparative study was conducted in Belgium and Chile. A total of 537 healthy infants, 270 in Chile and 267 in Belgium, received PRP-T and DTP vaccines combined in a dual-chamber syringe (D-Ch group, DTP/PRP-T, reconstituted by pressing the plunger of the syringe immediately before injection, n = 239) or combined in a single-chamber syringe (C-In group, DTP@PRP-T, reconstituted immediately before injection, n = 61) or in separate injections (S-In group, DTP + PRP-T, simultaneously injected at separate sites, n = 237) at 3, 4, and 5 months of age. Serum samples were collected before vaccination and at 6 months of age. In the D-Ch group, the incidence of adverse events was comparable to administration of DTP vaccine alone. Higher rates of local and systemic reactions were observed in the Chilean population, possibly due to differences in surveillance practice. The immune response to each vaccine component compared well to that of the separate administration of PRP-T and DTP vaccines, except for higher post-immunization anti-PRP geometric mean titre (GMT) values after separate injections (25.6 micrograms mL-1) than after combined injection with the dual-chamber syringe (17.6 micrograms mL-1) (p = 0.001). An unexpected 'syringe' effect was seen: a greater post-immunization anti-PRP GMT was observed in the D-Ch group (17.6 micrograms mL-1) than in the C-In group (7.7 micrograms mL-1) (p = 0.0001). Whereas pre-immunization GMTs of some antibodies were significantly lower in Chilean than in Belgian infants, the post-immunization GMTs of Chilean infants were two to three times greater for all of the antibodies studied (p < 0.005). Differences in reactogenicity and in the immune response between the study populations or the different vaccine presentations were striking, but are probably of no clinical relevance. The convenient dual-chamber syringe presentation of DTP and PRP-T vaccines is safe and highly immunogenic.