Baseline incidence of intussusception in early childhood before rotavirus vaccine introduction, the Netherlands, January 2008 to December 2012

Intussusception is a rare, potentially life-threatening condition in early childhood. It gained attention due to an unexpected association with the first rotavirus vaccine, RotaShield, which was subsequently withdrawn from the market. Across Europe, broad variations in intussusception incidence rates have been reported. This study provides a first estimate of intussusception incidence in young children in the Netherlands from 1 January 2008 to 31 December 2012, which could be used for future rotavirus safety monitoring. Our estimates are based on two different sources: electronic medical records from the primary healthcare database (IPCI), as well as administrative data from the Dutch hospital register (LBZ). The results from our study indicate a low rate of intussusception. Overall incidence rate in children < 36 months of age was 21.2 per 100,000 person-years (95% confidence interval (CI): 12.5–34.3) based on primary healthcare data and 22.6 per 100,000 person-years (95% CI: 20.9–24.4) based on hospital administrative data. The estimates suggest the upper and lower bound of the expected number of cases.

Differences by sex in IgG levels following infant and childhood vaccinations: An individual participant data meta-analysis of vaccination studies

BACKGROUND

If immune responses to vaccination differ between males and females, sex-specific vaccination schedules may be indicated. We systematically reanalysed childhood vaccination studies conducted in The Netherlands for sex-differences in IgG-responses. To assess the impact of potential sex-differences in IgG-responses, we explored sex-differences in vaccine failure/effectiveness and reactogenicity.

METHODS

Six studies with IgG-measurements for 1577 children following infant pneumococcal (PCV7/PCV10/PCV13) and/or DTaP-IPV-Hib(-HepB) vaccinations, or the pre-school DTaP-IPV booster were included. We performed one-stage individual participant data meta-analyses per time-point of the effect of sex on IgG levels against pneumococcal serotypes, diphtheria toxoid, tetanus toxoid, pertussis Ptx/FHA/Prn and Hib-PRP using linear mixed models. Using existing study data, we compared reactogenicity after PCV7/PCV10 and DTaP-IPV-Hib(-HepB) vaccination in girls and boys. Vaccine failure/effectiveness was compared between girls and boys for invasive pneumococcal disease (IPD), invasive Hib disease and pertussis using notification data.

RESULTS

For pneumococcal vaccination, the geometric mean concentration ratio of IgG levels in girls versus boys pooled across serotypes was 1.15 (95%CI 0.91-1.45) 1 month following the primary series, 1.16 (1.02-1.32) at age 8 months, 1.12 (1.02-1.23) pre-booster (age 11 months) and 0.99 (0.89-1.10) post-booster (age 12 months). Diphtheria toxoid, tetanus toxoid, pertussis Ptx/FHA/Prn and Hib-PRP IgG levels did not differ between girls and boys, except for Hib post-booster (1.24; 95%CI 1.01-1.52) and tetanus before pre-school booster (0.71; 0.53-0.95). We found no difference between boys and girls in reactogenicity at age 4 or 11 months or in vaccine failure/effectiveness for IPD, invasive Hib disease or pertussis.

CONCLUSION

For most vaccine antigens investigated, there were no consistent differences in vaccine-induced IgG levels. Vaccine-induced pneumococcal IgG levels were slightly higher in girls, but only between the primary series and the 11-month booster. These results, along with similar reactogenicity and vaccine failure/effectiveness, support the uniform infant vaccination schedule in the Dutch national immunisation programme.

Intention to vaccinate universally against varicella, rotavirus gastroenteritis, meningococcal B disease and seasonal influenza among parents in the Netherlands: an internet survey

Objective

For the decision-making process regarding introduction of new vaccines into the National Immunisation Programme (NIP), advance insight into the potential acceptance among the population is relevant. We studied the intention of parents to have their child vaccinated against four diseases not currently covered by the NIP in the Netherlands. The results on varicella have been published before; this article adds the results on vaccination against rotavirus gastroenteritis, meningococcal B disease, and seasonal influenza.

Results

We invited a random sample from the national immunisation register of 1500 parents for an internet survey which was completed by 491 parents (33% response). The intention to vaccinate was highest for meningococcal B disease (83% positive intention), followed by rotavirus gastroenteritis (38%), and lowest for varicella (28%) and seasonal influenza (15%). Prediction analyses were performed to determine which out of seven questionnaire statements was most informative in predicting the intention to vaccinate. Main drivers of intention were the perceived importance of vaccination against the particular disease and the perception of whether or not the disease is severe enough to justify vaccination. The results of this study can be informative in the decision-making process whether or not to introduce new vaccines into the NIP.

Electronic supplementary material

The online version of this article (10.1186/s13104-017-3004-z) contains supplementary material, which is available to authorized users.

Long-term impairment attributable to congenital cytomegalovirus infection: a retrospective cohort study

AIM

This study aimed to estimate long-term impairment attributable to congenital cytomegalovirus infection (cCMV).

METHOD

This nationwide cohort study retrospectively assessed cCMV in children born in 2008 in the Netherlands, testing 31 484 stored neonatal dried blood spots. Extensive medical data of cCMV-positive children (n=133) and matched cCMV-negative comparison children (n=274) up to 6 years of age were analysed.

RESULTS

Moderate to severe long-term impairment was diagnosed in 24.8% (33 out of 133) of all cCMV-positive children (53.8% in symptomatic, 17.8% in asymptomatic), compared with 12.0% (33 out of 274) of cCMV-negative children. Sensorineural hearing loss was seen only in five cCMV-positive children (3.8%). Developmental delays were diagnosed more often in cCMV-positive children than cCMV-negative children: motor (12.0% vs 1.5%), cognitive (6.0% vs 1.1%), and speech-language (16.5% vs 7.3%). Long-term impairment in multiple domains was more frequent in symptomatic (19.2%) and asymptomatic (8.4%) cCMV-positive children than cCMV-negative children (1.8%).

INTERPRETATION

Children with cCMV were twice as likely to have long-term impairment up to the age of 6 years, especially developmental delays and sensorineural hearing loss, than cCMV-negative comparison children, with a risk difference of 12.8%. These insights into the risk of cCMV-associated impairment can help optimize care and stimulate preventive measures.

WHAT THIS PAPER ADDS

Congenital cytomegalovirus infection (cCMV) leads to impairment in 25% of cases. Fifty per cent of children with cCMV symptoms at birth have long-term impairment. The risk difference of moderate to severe long-term impairment between children with and without cCMV is 13%, attributable to cCMV. cCMV leads to motor, cognitive, and speech-language developmental delay in children.

Informed decision making in the context of childhood immunization

OBJECTIVE

We aimed to assess informed decision making about childhood immunization by measuring knowledge, deliberation and value-consistency. Additionally, we investigated whether informed decision making is different for parents who accept and parents who decline vaccination.

METHODS

Parents of at least one child between 3 months and 3,5 years of age were randomly selected from a vaccination register and were asked to fill in an online questionnaire measuring informed decision making.

RESULTS

In total, 1615 parents completed the questionnaire (16.2%). 77.6% of the parents were classified as having sufficient knowledge, 34.3% of the decisions were deliberate, and 94% were value-consistent. This resulted in 21% of parents who were classified as making an informed decision. Vaccination decliners more often made a decision classified as informed than vaccination acceptors (34.3% vs. 19.7%). When decliners made a decision classified as uninformed, this was mainly due to insufficient knowledge, while uninformed decisions among acceptors were mainly due to a low level of deliberation.

CONCLUSION AND PRACTICE IMPLICATIONS

Most parents made an uninformed decision about childhood vaccinations. Decision aids and counseling by child vaccine providers could improve the knowledge of decliners and motivate acceptors to deliberate about their decision, and by that promote informed decision making.

Infectious reactivation of cytomegalovirus explaining age- and sex-specific patterns of seroprevalence

Human cytomegalovirus (CMV) is a herpes virus with poorly understood transmission dynamics. Person-to-person transmission is thought to occur primarily through transfer of saliva or urine, but no quantitative estimates are available for the contribution of different infection routes. Using data from a large population-based serological study (n = 5,179), we provide quantitative estimates of key epidemiological parameters, including the transmissibility of primary infection, reactivation, and re-infection. Mixture models are fitted to age- and sex-specific antibody response data from the Netherlands, showing that the data can be described by a model with three distributions of antibody measurements, i.e. uninfected, infected, and infected with increased antibody concentration. Estimates of seroprevalence increase gradually with age, such that at 80 years 73% (95%CrI: 64%-78%) of females and 62% (95%CrI: 55%-68%) of males are infected, while 57% (95%CrI: 47%-67%) of females and 37% (95%CrI: 28%-46%) of males have increased antibody concentration. Merging the statistical analyses with transmission models, we find that models with infectious reactivation (i.e. reactivation that can lead to the virus being transmitted to a novel host) fit the data significantly better than models without infectious reactivation. Estimated reactivation rates increase from low values in children to 2%-4% per year in women older than 50 years. The results advance a hypothesis in which transmission from adults after infectious reactivation is a key driver of transmission. We discuss the implications for control strategies aimed at reducing CMV infection in vulnerable groups.

Human cytomegalovirus (CMV) is a herpes virus causing lifelong infection. In high-income countries, the probability of infection increases gradually with age such that at old age up to 100% of the population is infected. CMV is thought to be transmitted mainly by transfer of saliva or urine, but little quantitative evidence is available about the transmission dynamics. We analyze serological data to estimate age- and sex-specific rates of infection, re-infection, and reactivation. The analyses show that infectious reactivation (i.e. reactivation of the virus in an infected person that is sufficient for it to be transmitted to another person) is essential to explain the data. We propose that infectious reactivation in adults is an important driver of transmission of CMV.

Effectiveness of a Web-Based Tailored Intervention With Virtual Assistants Promoting the Acceptability of HPV Vaccination Among Mothers of Invited Girls: Randomized Controlled Trial

BACKGROUND

In 2010, the human papillomavirus (HPV) vaccination was introduced in the Dutch National Immunization Program for 12-year-old girls, aiming to reduce the incidence of cervical cancer in women. HPV vaccination uptake turned out to be lower than expected: 61% versus 70%, respectively. Mothers were shown to play the most important role in the immunization decision about this vaccination. They had also expressed their need for interactive personal information about the HPV vaccination over and above the existing universal general information. To improve the effectiveness of the existing education about the HPV vaccination, we systematically developed a Web-based tailored intervention with virtual assistants providing mothers of girls to be invited with tailored feedback on their decision making about the HPV vaccination.

OBJECTIVE

The aim of this study was to evaluate the effectiveness of the Web-based tailored intervention for promoting HPV vaccination acceptance by means of a randomized controlled trial (RCT).

METHODS

Mothers were recruited via the Dutch vaccination register (Praeventis) (n=36,000) and three Web-based panels (n=2483). Those who gave informed consent (N=8062) were randomly assigned to the control (n=4067) or intervention condition (n=3995). HPV vaccination uptake, as registered by Praeventis once the HPV vaccination round was completed, was used as the primary outcome. Secondary outcomes were differential scores across conditions between baseline (before the provided access to the new tailored intervention) and follow-up (just before the first vaccination) regarding the mothers' degree of informed decision making (IDM), decisional conflict, and critical determinants of HPV vaccination uptake among which are intention, attitude, risk perception, and outcome beliefs.

RESULTS

Intention-to-treat analysis (N=8062) showed a significant positive effect of the intervention on IDM, decisional conflict, and nearly all determinants of HPV vaccination uptake (P<.001). No effect was found on uptake (P=.60). This may be attributed to the overall high uptake rates in both conditions. Mothers evaluated the intervention as highly positive, including the website as well as the virtual assistants that were used to deliver the tailored feedback.

CONCLUSIONS

This computer-tailored intervention has the potential to improve HPV vaccination acceptability and IDM and to decrease decisional conflict among mothers of invited girls. Implications for future research are discussed.

TRIAL REGISTRATION

Trialregister.nl NTR4935; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=4935 (Archived by WebCite at http://www.webcitation.org/6srT7l9EM).

Non-specific effects of measles, mumps, and rubella (MMR) vaccination in high income setting: population based cohort study in the Netherlands

Objectives To investigate whether measles, mumps, and rubella (MMR) vaccine has positive non-specific effects in a high income setting and to compare rates of hospital admissions for infections between children aged ≤2 years who received live MMR vaccine and those who received an inactivated vaccine against diphtheria, tetanus, pertussis, polio, and Haemophilus influenzae type b (DTaP-IPV-Hib) as their most recent vaccination.Design Nationwide population based cohort study.Setting In the Netherlands, DTaP-IPV-Hib+pneumococcal vaccination (PCV) is recommended at ages 2, 3, 4, and 11 months and MMR + meningococcal C (MenC) vaccination at age 14 months. Data from the national vaccine register were linked to hospital admission data.Participants 1 096 594 children born in 2005-11 who received the first four DTaP-IPV-Hib+PCV vaccines.Main outcome measures Hazard ratio for admission to hospital for infection in children with MMR+MenC compared with the fourth DTaP-IPV-Hib+PCV as their most recent vaccination. Cox regression was performed with most recent vaccination as time dependent variable, adjusted for potential confounders. Analyses were repeated with admission for injuries or poisoning as a negative control outcome. In addition, rate of admission for infection was compared between the fourth and third DTaP-IPV-Hib+PCVas most recent vaccination.Results Having had MMR+MenC as the most recent vaccination was associated with a hazard ratio of 0.62 (95% confidence interval 0.57 to 0.67) for admission to hospital for infection and 0.84 (0.73 to 0.96) for injuries or poisoning, compared with the fourth DTaP-IPV-Hib+PCV as most recent vaccination. The fourth DTaP-IPV-Hib+PCV as most recent vaccination was associated with a hazard ratio of 0.69 (0.63 to 0.76) for admission to hospital for infection, compared with the third DTaP-IPV-Hib+PCV as most recent vaccination.Conclusions Healthy vaccinee bias could at least partly explain the observed lower rate of admission to hospital with infection after MMR vaccination. The lower rate is associated with receipt of any additional vaccine, not specifically MMR vaccine. This emphasises the caution required in the interpretation of findings from observational studies on non-specific effects of vaccination.

The intention of Dutch general practitioners to offer vaccination against pneumococcal disease, herpes zoster and pertussis to people aged 60 years and older

BACKGROUND

Increasing life expectancy results in a larger proportion of older people susceptible to vaccine preventable diseases (VPDs). In the Netherlands, influenza vaccination is routinely offered to people aged 60 years and older. Vaccination against pneumococcal disease, herpes zoster and pertussis is rarely used. These vaccines will be evaluated by the Dutch Health Council and might be routinely offered to older people in the near future. Possible expansion of the program depends partly on the willingness of general practitioners (GPs) to endorse additional vaccinations. In this study, we assessed predictors of GPs' attitude and intention to vaccinate people aged 60 years and older.

METHODS

GPs (N = 12.194) were invited to fill in an online questionnaire consisting of questions about social cognitive factors that can influence the willingness of GPs to vaccinate people aged 60 years and older, including underlying beliefs, practical considerations of adding more vaccines to the national program, demographics, and GPs' patient population characteristics. The questionnaire was filled in by 732 GPs.

RESULTS

GPs were positive both about vaccination as a preventive tool and the influenza vaccination program, but somewhat less positive about expanding the current program. Prediction analysis showed that the intention of GPs to offer additional vaccination was predicted by their attitude towards offering additional vaccination, towards vaccination as a preventive tool, towards offering vaccination during an outbreak and on GPs opinion regarding suitability to offer additional vaccination (R2 = 0.60). The attitude of GPs towards offering additional vaccination was predicted by the perceived severity of herpes zoster and pneumonia, as well as the perceived incidence of herpes zoster. Severity of diseases was ranked as important argument to recommend vaccination, followed by effectiveness and health benefits of vaccines.

CONCLUSION

Providing GPs with evidence-based information about the severity and prevalence of diseases, and effectiveness and health benefits of the vaccines, together with an active role of GPs in informing older people about vaccines, could modify the intention towards additional vaccination of people 60 years and older.

Dutch national immunization schedule: compliance and associated characteristics for the primary series

In the Netherlands, the recommended priming immunization schedule for diphtheria, tetanus, pertussis and polio (DTaP-IPV) is at 2, 3 and 4 months of age. We evaluated the compliance with the recommended schedule, as well as its characteristics. We included all infants born between 2007 and 2012 who received minimally one DTaP-IPV vaccination (n = 1,061,578). Infants complied with the schedule if they received the first vaccination between 6 and 9 weeks of age, and the second and third vaccination 2-6 weeks after the first and second vaccination. We examined associations between compliance and several characteristics using log-binomial regression. Compliance for the first, second and third vaccination was 81.6, 88.3 and 84.2%, respectively. Compliance with the total recommended schedule was 64.5%, and increased from 60.1% for 2007 to 68.5% for 2012. Compliance was higher for full-term infants (65.9%), infants with normal birth weight (66.0%) and when both parents were born in the Netherlands (66.8%).

CONCLUSION

Delayed vaccination during the primary vaccination schedule occurs in one sixth of the Dutch children. Efforts to improve compliance should be focused in particular on preterm infants, infants with low birth weight and infants whose parents are not born in the Netherlands. What is Known: • A delayed start of vaccination leads to a longer period at risk for infectious diseases, e.g. pertussis • Delayed vaccination is associated with several factors including prematurity, low birth weight, family size, birth order, low socioeconomic status and health status of the child What is New: • Compliance with the recommended priming immunization schedule for diphtheria, tetanus, pertussis and polio was 64.5%, and increased from 60.1% for 2007 to 68.5% for 2012 • If the first vaccination was delayed, there was a higher chance that the following vaccinations were administered 'out-of-schedule' as well, resulting in even a higher age at second and third vaccination.

Comparison of the tolerability of newly introduced childhood vaccines in the Netherlands

In 2011, the 7-valent conjugated pneumococcal vaccine (PCV7) was replaced by the 10-valent vaccine (PCV10) and universal hepatitis B vaccination has been introduced in the Netherlands. A questionnaire study was conducted to assess the tolerability of DTaP-IPV-Hib + PCV7 (PCV7-cohort), DTaP-IPV-Hib + PCV10 (PCV10-cohort), and DTaP-IPV-Hib-HepB + PCV10 (HepB-cohort). Parents were asked to report in questionnaires local reactions and systemic adverse events (AEs) before and after vaccination of their infant at 2, 3, 4, and 11 months of age. For 29.0 and 29.4% infants of the PCV7-cohort, at least one local reaction was reported in the week after the first dose of DTaP-IPV (left leg) and PCV-7 vaccination (right leg). Significantly more infants from the PCV10-cohort (45.1%, p < 0.001 and 44.6%, p < 0.001) and HepB-cohort (42.6%, p < 0.001 and 41.9%, p < 0.001) reported at least one local reaction. This effect was less pronounced after the successive doses. Most of the infants experienced at least one systemic AE, and after dose 4, this was higher for infants in the PCV10-cohort (65.9%, p = 0.047) and HepB-cohort (70.6%, p = 0.000) compared to the PCV7-cohort (62.3%).

CONCLUSION

Addition of antigens to a vaccine resulted in a higher reactogenicity, but the AEs were in general mild and transient. What is Known: • Assessment of adverse events is crucial for achieving the highest safety in immunization programs, in order to inform public health actions and maintain public confidence in immunization programs. What is New: • Newly introduced vaccines DTaP-IPV-Hib-HepB and PCV10 are generally safe and well tolerated in infants. • These results are useful for information purposes and for monitoring variations in rates of AEs in the general population or in the target group over time.

Large measles epidemic in the Netherlands, May 2013 to March 2014: changing epidemiology

Since the early 1990s, the Netherlands has experienced several large measles epidemics, in 1992–94, 1999–2000 and in 2013–14. These outbreaks mainly affected orthodox Protestants, a geographically clustered population with overall lower measles-mumps-rubella first dose (MMR-1) vaccination coverage (60%) than the rest of the country (> 95%). In the 2013–14 epidemic described here, which occurred between 27 May 2013 and 12 March 2014, 2,700 cases were reported. Several control measures were implemented including MMR vaccination for 6–14-month-olds and recommendations to reduce the risk in healthcare workers. The vast majority of reported cases were unvaccinated (94%, n = 2,539), mostly for religious reasons (84%, n = 2,135). The median age in the epidemic was 10 years, 4 years older than in the previous epidemic in 1999–2000. A likely explanation is that the inter-epidemic interval before the 2013–2014 epidemic was longer than the interval before the 1999–2000 epidemic. The size of the unvaccinated orthodox Protestant community is insufficient to allow endemic transmission of measles in the Netherlands. However, large epidemics are expected in the future, which is likely to interfere with measles elimination in the Netherlands and elsewhere.

Sex differences in invasive pneumococcal disease and the impact of pneumococcal conjugate vaccination in the Netherlands, 2004 to 2015

Implementation of pneumococcal conjugate vaccines in the Netherlands (PCV7 in 2006 and PCV10 in 2011) for infants caused a shift in serotypes in invasive pneumococcal disease (IPD). We explored sex differences in serotype-specific IPD incidence before and after vaccine introduction. Incidences in the pre-PCV7 (June 2004–May 2006), post-PCV7 (June 2008–May 2011) and post-PCV10 period (June 2013–May 2015), stratified by age, were compared. Incidence was higher in men for all age groups (overall in men: 16.7, 15.5 and 14.4/100,000 and women: 15.4, 13.6 and 13.9/100,000 pre-PCV7, post-PCV7 and post-PCV10, respectively), except for 20–39 year-olds after PCV7 and 40–64 year-olds after PCV10 introduction. After PCV7 and PCV10 introduction, the overall IPD incidence decreased in men aged 20–39 years (from 5.3 pre-PCV7 to 4.7 and 2.6/100,000 post-PCV7 and post-PCV10, respectively), whereas it showed a temporary increase in women (from 3.9/100,000 pre-PCV7 to 5.0/100,000 post-PCV7 and back to 4.0/100,000 post-PCV10) due to replacement disease. PCV10 herd effects were observed throughout, but in women older than 40 years, a significant increase in non-PCV10 serotype offset a decrease in overall IPD incidence. Ongoing surveillance of IPD incidence by sex is important to evaluate the long-term effects of PCV implementation.

Long-term mortality after IPD and bacteremic versus non-bacteremic pneumococcal pneumonia

BACKGROUND

Short-term mortality after invasive pneumococcal disease (IPD) and pneumococcal pneumonia is high but data on long-term mortality (including the comparison between bacteremic and non-invasive/non-bacteremic pneumococcal pneumonia) within the first years after diagnosis are scarce.

METHODS

Adult patients with 'non-pneumonia' IPD and 'invasive pneumonia' (from 2004 to 2012) and with 'bacteremic' vs 'non-invasive/non-bacteremic (NI/NB)' pneumococcal pneumonia (from 2008 to 2012) diagnosed by negative blood culture but a positive urinary antigen test (UAT) were identified in a Dutch hospital. Mortality of patients up to 10years after diagnosis was compared with age- and sex-matched life-expectancy data of the general population. Multivariable Cox regression analysis was used to study predictors for mortality in invasive pneumonia patients and to adjust for confounders comparing mortality between bacteremic and NI/NB/UAT-positive pneumonia patients.

RESULTS

Of 228 invasive pneumonia patients 17% died within 30days and in 30-day survivors cumulative long-term mortality at 1 and 5years were 16% and 39% as compared with 3% and 15% in age- and sex-matched persons. High mortality was largely dependent on pre-existent comorbidities. In invasive pneumonia patients who survived the first 30days, age, male gender, chronic cardiovascular disease, malignancy and PCV7 serotype disease were independent predictors for higher long-term mortality. For bacteremic pneumonia patients (n=128) 30-day mortality was 16% and almost similar to 14% in NI/NB/UAT-positive pneumococcal pneumonia patients (n=170). In 30-day survivors of bacteremic pneumonia (n=108, median age 66years), cumulative mortality at 1 and 3years were 13% and 29% as compared with 18% and 40% in NI/NB/UAT-positive pneumococcal pneumonia patients (n=146, median age 67years) without a significant difference in mortality.

CONCLUSIONS

Approximately 40% of all patients, who survived the first 30days after presentation with non-pneumonia IPD and pneumococcal pneumonia died within the following 5years. High long-term mortality was largely dependent on pre-existent comorbidity.

A longitudinal study on determinants of HPV vaccination uptake in parents/guardians from different ethnic backgrounds in Amsterdam, the Netherlands

BACKGROUND

Human papillomavirus (HPV) vaccination coverage in the Netherlands is low (~60%) compared to other childhood vaccinations (>90%), and even lower among ethnic minorities. The aim of this study was to explore the possible impact of ethnicity on the determinants of both HPV vaccination intention and HPV vaccination uptake among parents/guardians having a daughter that is invited for the HPV vaccination.

METHODS

In February 2014, parents/guardians living in Amsterdam were invited to complete a questionnaire about social-psychological determinants of their decision making process regarding the HPV vaccination of their daughter and socio-demographic characteristics. This questionnaire was sent approximately one month before the daughter was scheduled to receive her first HPV vaccine dose. Their daughters' HPV vaccination status was retrieved from the national vaccination database. We distinguished four ethnic groups: Dutch (NL), Surinamese, Netherlands Antillean, and Aruban (SNA), Middle-Eastern and North-African (MENA), and Other. To assess the impact of determinants on both intention and uptake, linear and logistic regression analyses were used respectively. Missing data were imputed using multiple imputation by chained equation.

RESULTS

In total 1,309 parents/guardians participated (33% participation rate). In all groups we found the mothers' intention to be the strongest predictor of their daughters' HPV vaccination uptake. Explained variance of uptake was highest in the NL-group (pseudo-R²:0.56) and lower in the other ethnic groups (pseudo-R² varied between 0.23 and 0.29). The lower explained variance can be attributed to the relative large proportion of participants with a positive intention that finally did not go for vaccination in the SNA-group (11%) and MENA-group (30%). Explained variance (R²) of intention varied between 0.66 and 0.77 across ethnic groups, and was best explained by the proximal social-psychological determinants. The strength of association of these determinants with both intention and uptake were largely similar across ethnic groups.

CONCLUSION

We conclude that the same determinants should be targeted in the different ethnic groups, although the mode of delivery of the intervention needs to be tailored to the different cultural backgrounds. Further research is needed to explain the observed discrepancy between intention and uptake, especially among parents/guardians in the non-Dutch groups.

Disease burden of human papillomavirus infection in the Netherlands, 1989-2014: the gap between females and males is diminishing

PURPOSE

Besides cervical cancer, HPV infection is linked to a multitude of diseases in both males and females, suggesting that vaccination programmes should be re-evaluated, with a judicious assessment made of the disease burden stratified by sex, age, and genotype. Projections of burden into the near future are also needed to provide a benchmark for evaluating the impact of vaccination programmes, and to assess the need for scaling-up preventive measures.

METHODS

Using the disability-adjusted life-years (DALY) measure, we estimated the total HPV-associated disease burden in the Netherlands. Annual cancer registrations over the period 1989-2014 for all cancers with an aetiological link to HPV infection were retrieved, supplemented by incidence data on high-grade cervical intraepithelial neoplasia (CIN) and anogenital warts.

RESULTS

Over the recent period 2011-2014, the average annual HPV disease burden was 10,600 DALYs (95% credible interval (CrI):10,260-10,960) in females and 3,346 DALYs (95% CrI: 2,973-3,762) in males. Burden was dominated by cervical cancer, but its share amongst women decreased from 89% in 1989 to 77% in 2014. The male share of the total disease burden increased from 9.8% in 1989 to 26% in 2014. In 2023 (before the expected clinical impact from vaccinating girls), total burden is forecasted at 1.3-fold larger than in 2014.

CONCLUSIONS

The HPV-associated disease burden is higher than that reported for any other infectious disease in the Netherlands, with a larger burden observed in women than in men. The rapidly rising male share of the total burden underlines the prioritization of male HPV-related disease in prevention programmes.

The whole story: a systematic review of economic evaluations of HPV vaccination including non-cervical HPV-associated diseases

INTRODUCTION

Many economic evaluations of HPV vaccination have been published, but most have focused on the prevention of cervical disease as a primary health outcome. The cost-effectiveness of vaccination is likely to be underestimated if not all HPV-associated diseases are taken into account. In this review, we assess the influence of non-cervical HPV-associated diseases on the incremental cost-effectiveness ratio (ICER) of preadolescent HPV vaccination. Areas covered: We systematically searched the literature and identified 18 studies that included non-cervical diseases in the estimates of cost-effectiveness of HPV-vaccination. When taking other HPV-related diseases into account compared to not including such other diseases, the mean ICERs were 2.85 times more favorable for girls only vaccination and 3.89 times for gender neutral vaccination. Expert commentary: Including non-cervical diseases in economic evaluations of HPV vaccination programs makes it more likely that the ICER falls beneath accepted cost-effectiveness thresholds and therefore increases the scope for gender neutral vaccination.

Herpes simplex virus type 1 and type 2 in the Netherlands: seroprevalence, risk factors and changes during a 12-year period

Background

Genital herpes results in considerable morbidity, including risk of neonatal herpes, and is increasingly being caused by Herpes Simplex Virus (HSV) type 1. Possibly children are less often HSV-1 infected, leaving them susceptible until sexual debut. We assessed changes in the Dutch HSV-1 and HSV-2 seroprevalence over time and determinants associated with HSV seropositivity.

Methods

We used data from two population-based seroepidemiological studies conducted in 1995–6 and 2006–7 with a similar study design. Serum samples of 6 months to 44-year-old participants were tested for type-specific HSV antibodies using HerpesSelect® with a cut-off level of >1.10 for seropositivity. Age and sex-specific HSV-1 and HSV-2 seroprevalence was weighted for the Dutch population. Logistic regression was performed to investigate determinants associated with HSV seropositivity.

Results

Overall, weighted HSV-1 seroprevalence was significantly lower in 2006–7 [42.7 % 95 % confidence interval (CI) 39.9-45.4] than in 1995–6 (47.7 % 95 % CI 44.8-50.7), especially among 10- to 14-year-olds. Overall, weighted HSV-2 seroprevalence remained stable: 6.8 % in 1995–6 and 6.0 % in 2006–7. Adults who ever had sexual intercourse were more often seropositive for HSV-1 [adjusted Odds Ratio (aOR) 1.69 95 % CI 1.33-2.16] and HSV-2 (aOR 2.35 95 % CI 1.23-4.52). Age at sexual debut was the only sexual risk determinant associated with HSV-1 seropositivity.

Conclusions

Because of the lower HSV-1 seroprevalence in 2006–7 compared to 1995–6, more adults are susceptible to genital HSV-1, including women of reproductive age. Given the higher risk of neonatal herpes when HSV is acquired during pregnancy, prevention and control measures during pregnancy also targeting HSV-1, are important.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1707-8) contains supplementary material, which is available to authorized users.

Mumps-specific cross-neutralization by MMR vaccine-induced antibodies predicts protection against mumps virus infection

BACKGROUND

Similar to other recent mumps genotype G outbreaks worldwide, most mumps patients during the recent mumps genotype G outbreaks in the Netherlands had received 2 doses of measles, mumps and rubella (MMR) vaccine during childhood. Here, we investigate the capacity of vaccine-induced antibodies to neutralize wild type mumps virus strains, including mumps virus genotype G.

METHODS

In this study, we tested 105 pre-outbreak serum samples from students who had received 2 MMR vaccine doses and who had no mumps virus infection (n=76), symptomatic mumps virus infection (n=10) or asymptomatic mumps virus infection (n=19) during the mumps outbreaks. In all samples, mumps-specific IgG concentrations were measured by multiplex immunoassay and neutralization titers were measured against the Jeryl Lynn vaccine strain and against wild type genotype G and genotype D mumps virus strains.

RESULTS

The correlation between mumps-specific IgG concentrations and neutralization titers against Jeryl Lynn was poor, which suggests that IgG concentrations do not adequately represent immunological protection against mumps virus infection by antibody neutralization. Pre-outbreak neutralization titers in infected persons were significantly lower against genotype G than against the vaccine strain. Furthermore, antibody neutralization of wild type mumps virus genotype G and genotype D was significantly reduced in pre-outbreak samples from infected persons as compared with non-infected persons. No statistically significant difference was found for the vaccine strain. The sensitivity/specificity ratio was largest for neutralization of the genotype G strain as compared with the genotype D strain and the vaccine strain.

CONCLUSIONS

The reduced neutralization of wild type mumps virus strains in MMR vaccinated persons prior to infection indicates that pre-outbreak mumps virus neutralization is partly strain-specific and that neutralization differs between infected and non-infected persons. Therefore, we recommend the use of wild type mumps virus neutralization assays as preferred tool for surveillance of protection against mumps virus infection.

Invasive Pneumococcal Disease 3 Years after Introduction of 10-Valent Pneumococcal Conjugate Vaccine, the Netherlands

Three years after a 7-valent pneumococcal conjugate vaccine was replaced by a 10-valent pneumococcal conjugate vaccine in the Netherlands, we observed a decrease in incidence of invasive pneumococcal disease caused by Streptococcus pneumoniae serotypes 1, 5, and 7F. Our data do not support or exclude cross-protection against serotype 19A.

Economic Costs of Measles Outbreak in the Netherlands, 2013-2014

In 2013 and 2014, the Netherlands experienced a measles outbreak in orthodox Protestant communities with low measles–mumps–rubella vaccination coverage. Assessing total outbreak costs is needed for public health outbreak preparedness and control. Total costs of this outbreak were an estimated $4.7 million.

An exploration of individual- and population-level impact of the 2-dose HPV vaccination schedule in pre-adolescent girls

Since 2014, several countries have implemented a 2-dose schedule for Human papillomavirus (HPV) vaccination. Licensure of the 2-dose schedule was based on non-inferiority results from immunobridging studies, comparing the antibody levels of the 2-dose schedule in young girls to those of the 3-dose schedule in young adults. Since licensure, additional data on antibody levels and other aspects of the immune response and clinical effectiveness have become available. This review will discuss the current outcomes on immunogenicity and effectiveness together with an exploration on the population impact of 2-dose schedules from a cost-effectiveness perspective. The 2-dose schedule has important benefits, such as easier logistics, reduced expenditure, potentially higher acceptance and fewer side effects. Policymakers and registration authorities should consider whether these benefits outweigh the likely differences on individual- and population-level impact between the 2- and 3-dose schedules.