Margareta Blennow

Outdoor environmental assessment of attention promoting settings for preschool children.

The restorative potential of green outdoor environments for children in preschool settings was investigated by measuring the attention of children playing in settings with different environmental features. Eleven preschools with outdoor environments typical for the Stockholm area were assessed using the outdoor play environment categories (OPEC) and the fraction of visible sky from play structures (sky view factor), and 198 children, aged 4.5-6.5 years, were rated by the staff for inattentive, hyperactive and impulsive behaviors with the ECADDES tool. Children playing in large and integrated outdoor areas containing large areas of trees, shrubbery and a hilly terrain showed less often behaviors of inattention (p<.05). The choice of tool for assessment of attention is discussed in relation to outdoor stay and play characteristics in Swedish preschool settings. The results indicate that the restorative potential of green outdoor environments applies also to preschool children and that environmental assessment tools as OPEC can be useful when to locate and develop health-promoting land adjacent to preschools.

Immunoglobulin E Response to Pertussis Toxin in Whooping Cough and after Immunization with a Whole-Cell and an Acellular Pertussis Vaccine

Immunoglobulin E antibodies to pertussis toxin (PT-IgE) were demonstrated in 15 of 23 (65%) patients with culture-confirmed pertussis. In 6 individuals there was a low-grade PT-IgE response after 6-9 weeks of disease and in 9 a rapid PT-IgE response, appearing 1-3 weeks after onset of symptoms. The PT-IgE antibody levels in immunized individuals were higher than in the non immunized. Following primary immunization of 23 children with a monovalent whole-cell pertussis vaccine (Burroughs-Wellcome, UK) or with an acellular pertussis vaccine (JNIH-6, Biken, Japan) a late low-grade PT-IgE response was found in 8 (35%). In 7/10 children previously immunized with the JNIH-6, a booster injection 16 months later with the same vaccine resulted in a rapidly appearing PT-IgE antibody response. In contrast, none of 13 children initially immunized with the monovalent whole-cell vaccine and then boostered with either this vaccine or JNIH-6 had detectable PT-IgE antibodies after the booster injection. The study shows that IgE-antibodies to pertussis toxin commonly appear in patients with whooping cough and that the kinetics and the magnitude of the response is influenced by previous exposure to the antigen. A PT-IgE response may also follow pertussis immunization.

Effects of PCV7 and PCV13 on invasive pneumococcal disease and carriage in Stockholm, Sweden.

The effects of pneumococcal conjugated vaccines (PCVs) need to be investigated. In Stockholm County, Sweden, PCV7 was introduced in the childhood immunisation programme in 2007 and changed to PCV13 in 2010. Over 90% of all invasive isolates during 2005–2014 (n=2336) and carriage isolates, 260 before and 647 after vaccine introduction, were characterised by serotyping, molecular typing and antibiotic susceptibility, and serotype diversity was calculated. Clinical information was collected for children and adults with invasive pneumococcal disease (IPD). The IPD incidence decreased post-PCV7, but not post-PCV13, in vaccinated children. Beneficial herd effects were seen in older children and adults, but not in the elderly. The herd protection was more pronounced post-PCV7 than post-PCV13. PCV7 serotypes decreased. IPD caused by PCV13 serotypes 3 and 19A increased post-PCV7. Post-PCV13, serotypes 6A and 19A, but not serotype 3, decreased. The serotype distribution changed in carriage and IPD to nonvaccine types, also in nonvaccinated populations. Expansion of non-PCV13 serotypes was largest following PCV13 introduction. Serotype diversity increased and nonvaccine clones emerged, such as CC433 (serotype 22F) in IPD and CC62 (serotype 11A) in carriage. In young children, meningitis, septicaemia and severe rhinosinusitis, but not bacteraemic pneumonia, decreased. Pneumococcal vaccination leads to expansion of new or minor serotypes/clones, also in nonvaccinated populations. New or minor serotypes/clones expanded, also in nonvaccinated populations, affecting future vaccine strategies http://ow.ly/VA9EO

Clinical symptoms and social factors in a cohort of children spontaneously clearing Helicobacter pylori infection

Tindberg Y, Blennow M, Granström M. Clinical symptoms and social factors in a cohort of children spontaneously clearing Helicobacter pylori infection. Acta Pædiatr 1999; 88: 631‐5. Stockholm. ISSN 0803‐5253

A ten year follow-up after immunization with a two component acellular pertussis vaccine.

OBJECTIVES To investigate the duration of antitoxin response and immunity to pertussis 10 years after priming with either two or three doses of a two component acellular pertussis vaccine or with three doses of a whole cell vaccine and then boostered with the acellular vaccine. SUBJECTS At 11 years of age 207 of 304 (68%) children of the original cohort returned for a blood sample and 262 (86%) participated by answering a questionnaire. METHODS Neutralizing antibodies to pertussis toxin (antitoxin) were analyzed by the Chinese hamster ovary cell assay. Clinical pertussis and pertussis exposure were investigated by a structured questionnaire. RESULTS Measurable antitoxin was found in 77% of the samples, with no differences by type of vaccine or by the number of doses given for priming. A significant decrease of antibody concentration (P<0.001) was noted from the previous recall at 4 years of age, and significant titer rises were found for 14% of the children, irrespective of known exposure. Confirmed pertussis during follow-up, as defined in the study, was reported for 14 of 262 (5%) children. CONCLUSIONS The study showed that antitoxin concentrations are maintained in a situation of endemic pertussis and indicated that the long term protection after an acellular booster was good, irrespective of type of vaccine or the number of doses of acellular vaccine given for priming.

The quality of the outdoor environment influences childrens health- a cross sectional study of preschools

To test how the quality of the outdoor environment of child day care centres (DCCs) influences childrens health.

Sinusitis and Pneumonia Hospitalization After Introduction of Pneumococcal Conjugate Vaccine

BACKGROUND AND OBJECTIVE: Streptococcus pneumoniae is a major cause of pneumonia and sinusitis. Pneumonia kills >1 million children annually, and sinusitis is a potentially serious pediatric disease that increases the risk of orbital and intracranial complications. Although pneumococcal conjugate vaccine (PCV) is effective against invasive pneumococcal disease, its effectiveness against pneumonia is less consistent, and its effect on sinusitis is not known. We compared hospitalization rates due to sinusitis, pneumonia, and empyema before and after sequential introduction of PCV7 and PCV13. METHOD: All children 0 to <18 years old hospitalized for sinusitis, pneumonia, or empyema in Stockholm County, Sweden, from 2003 to 2012 were included in a population-based study of hospital registry data on hospitalizations due to sinusitis, pneumonia, or empyema. Trend analysis, incidence rates, and rate ratios (RRs) were calculated comparing July 2003 to June 2007 with July 2008 to June 2012, excluding the year of PCV7 introduction. RESULTS: Hospitalizations for sinusitis decreased significantly in children aged 0 to <2 years, from 70 to 24 cases per 100 000 population (RR = 0.34, P < .001). Hospitalizations for pneumonia decreased significantly in children aged 0 to <2 years, from 450 to 366 per 100 000 population (RR = 0.81, P < .001) and in those aged 2 to <5 years from 250 to 212 per 100 000 population (RR = 0.85, P = .002). Hospitalization for empyema increased nonsignificantly. Trend analyses showed increasing hospitalization for pneumonia in children 0 to <2 years before intervention and confirmed a decrease in hospitalizations for sinusitis and pneumonia in children aged 0 to <5 years after intervention. CONCLUSIONS: PCV7 and PCV13 vaccination led to a 66% lower risk of hospitalization for sinusitis and 19% lower risk of hospitalization for pneumonia in children aged 0 to <2 years, in a comparison of 4 years before and 4 years after vaccine introduction.

Adverse reactions after diphtheria-tetanus booster in 10-year-old schoolchildren in relation to the type of vaccine given for the primary vaccination.

This prospective open study investigated adverse reactions in 527 schoolchildren to a diphtheria-tetanus (DT) booster given within a national vaccination programme at 10 years of age. Evaluation was based on those whose immunization records showed that they had received either three doses of an adsorbed DT vaccine (n = 388) or a non-adsorbed DT-pertussis vaccine (DTP) (n = 69) for primary series vaccination. No differences in systemic reactions to the booster between the two groups were observed. Local reactions were significantly (p < 0.001) more common 1 day after vaccination in children who had received DT for primary series vaccination: redness, 73% compared with 23%; swelling, 56% versus 15%; and itching, 47% versus 21%. One and 2 weeks after the booster, itching was still more pronounced in the group who had received DT for primary series vaccination (p < 0.001 and 0.014, respectively). The study indicates that there was a real basis for the increase in spontaneous notifications of local side-effects to the school DT booster in Sweden. The most likely cause for the increase seems to be the aluminium adjuvant in the vaccine given for primary vaccination, a late and unexpected consequence of a change in the infant immunization programme.

Long term serologic follow-up after pertussis immunization.

Neutralizing antibodies to pertussis toxin (antitoxin) were determined in 201 blood samples from 4-year-old children. They had received primary immunization at 6 to 8 months of age with an acellular (n = 149) or a whole cell (n = 52) pertussis vaccine and 195 of them had received a booster dose of the acellular vaccine 9 to 16 months later. Data on exposure to pertussis and occurrence of pertussis were also collected. There was a rapid decrease of antitoxin between immediate postbooster titers and those measured 24 months later. This decrease per month was significantly greater than that after the primary immunization series (P < 0.001). Neither the number nor the spacing of acellular vaccine doses given for primary series influenced the titers found 24 months after the booster. An antitoxin response was still measurable in 86% of the 196 four-year-old children. None of 19 exposed children developed whooping cough, which suggested that the antibody concentrations during the follow-up period were sufficient for protection. The results indicate a need for long term follow-up studies in the evaluation of new vaccines and immunization schedules.

Unaltered pneumococcal carriage prevalence due to expansion of non-vaccine types of low invasive potential 8 years after vaccine introduction in Stockholm, Sweden

OBJECTIVE To evaluate the carriage prevalence, serotype distribution, and antibiotic resistance for pneumococcal carriage isolates collected 4-8years after introduction of pneumococcal conjugate vaccines (PCVs) in Stockholm, Sweden, and to identify risk factors for carriage and calculate the invasive disease potential for emerging serotypes. METHODS Nasopharyngeal aspirates were collected from 3024 children aged 0-<5years at regular visits at 23 Child Health Centers in Stockholm County in 2011-2015, and from 787 parents in 2014-2015. The invasive disease potential was calculated for serotypes using invasive disease isolates from 824 patients of all ages identified in the Stockholm County during the same time period as the carriage isolates. RESULTS A total carriage prevalence of 30% did not change during the study period. Non-vaccine types (NVT) dominated (94% by 2015) and the most common serotypes in descending order were 11A, 23B, 35F and 21. Risk factors for carriage were: age ⩾3months-<3years, having siblings, attending day-care and having travelled abroad the last 3months. Antibiotic resistance remained low. The invasive disease potential was high for NVT 8, 9N, 12F, and 22F, while low for a majority of emerging NVTs in carriage. CONCLUSION The carriage prevalence remained the same 4-8years after vaccine introduction, but serotype replacement became almost complete. A majority of emerging NVTs in carriage showed a low invasive disease potential. Carriage studies are an important complement to invasive disease surveillance to understand the full effect of PCV vaccine programs.