Päivi Olsén

AS03 Adjuvanted AH1N1 Vaccine Associated with an Abrupt Increase in the Incidence of Childhood Narcolepsy in Finland

Background Narcolepsy is a chronic sleep disorder with strong genetic predisposition causing excessive daytime sleepiness and cataplexy. A sudden increase in childhood narcolepsy was observed in Finland soon after pandemic influenza epidemic and vaccination with ASO3-adjuvanted Pandemrix. No increase was observed in other age groups. Methods Retrospective cohort study. From January 1, 2009 to December 31, 2010 we retrospectively followed the cohort of all children living in Finland and born from January 1991 through December 2005. Vaccination data of the whole population was obtained from primary health care databases. All new cases with assigned ICD-10 code of narcolepsy were identified and the medical records reviewed by two experts to classify the diagnosis of narcolepsy according to the Brighton collaboration criteria. Onset of narcolepsy was defined as the first documented contact to health care because of excessive daytime sleepiness. The primary follow-up period was restricted to August 15, 2010, the day before media attention on post-vaccination narcolepsy started. Findings Vaccination coverage in the cohort was 75%. Of the 67 confirmed cases of narcolepsy, 46 vaccinated and 7 unvaccinated were included in the primary analysis. The incidence of narcolepsy was 9.0 in the vaccinated as compared to 0.7/100,000 person years in the unvaccinated individuals, the rate ratio being 12.7 (95% confidence interval 6.1–30.8). The vaccine-attributable risk of developing narcolepsy was 1∶16,000 vaccinated 4 to 19-year-olds (95% confidence interval 1∶13,000–1∶21,000). Conclusions Pandemrix vaccine contributed to the onset of narcolepsy among those 4 to 19 years old during the pandemic influenza in 2009–2010 in Finland. Further studies are needed to determine whether this observation exists in other populations and to elucidate potential underlying immunological mechanism. The role of the adjuvant in particular warrants further research before drawing conclusions about the use of adjuvanted pandemic vaccines in the future.

Neurodevelopmental outcome at 5 years of age of a national cohort of extremely low birth weight infants who were born in 1996-1997

Objective. Increasing survival of extremely low birth weight (ELBW; birth weight <1000 g) infants raises a concern regarding the risks of adverse long-term outcome such as cognitive dysfunction. Few studies have reported long-term follow-up of representative regional cohorts. The objective of this study was to assess the 5-year outcome of a prospectively followed national ELBW infant cohort. Methods. Of all live-born ELBW infants (n = 351) who were delivered in the 2-year period 1996–1997 in Finland, 206 (59%) survived until the age of 5 years. Of these, 103 were born at <27 gestational weeks (GW). A total of 172 children were assessed with neurocognitive tests (Wechsler Preschool and Primary Scale of Intelligence–Revised and a Developmental Neuropsychological Assessment [NEPSY]). Nine children with cognitive impairment and inability to cooperate in testing were not assessed. Motor development was assessed with a modified Touwen test. Results. The rate of cognitive impairment in the ELBW survivors was 9%. The rate of cerebral palsy was 14% (19% of ELBW infants who were born at <27 GW). The mean full-scale IQ of the assessed children was 96 ± 19 and in children of GW <27 was 94 ± 19. Attention, language, sensorimotor, visuospatial, and verbal memory values of NEPSY assessment were significantly poorer compared with normal population means. Four percent needed a hearing aid, and 30% had ophthalmic findings. Of 21 children who had been treated with laser/cryo for retinopathy of prematurity, 17 (81%) had abnormal ophthalmic findings. Of the whole cohort, 41 (20%) exhibited major disabilities, 38 (19%) exhibited minor disabilities, and 124 (61%) showed development with no functional abnormalities but subtle departures from the norm. Only 53 (26%) of the total ELBW infant cohort were classified to have normal outcome excluding any abnormal ophthalmic, auditory, neurologic, or developmental findings. Being small for gestational age at birth was associated with suboptimal growth at least until age 5. Conclusions. Only one fourth of the ELBW infants were classified as normally developed at age 5. The high rate of cognitive dysfunction suggests an increased risk for learning difficulties that needs to be evaluated at a later age. Extended follow-up should be the rule in outcome studies of ELBW infant cohorts to elucidate the impact of immaturity on school achievement and social behavior later in life.

Psychological findings in preterm children related to neurologic status and magnetic resonance imaging.

Objective.u2003Preterm children experience learning disabilities more often than full-term children, but detailed information on their neuropsychological and neurologic determinants is lacking. We therefore examined these problems more closely and also studied if clinical neurologic examination and/or magnetic resonance imaging (MRI) can be used as tools to screen the preterm children at risk for these problems. Methods.u2003In a population-based study, the psychological performance of 42 preterm children with a birth weight <1750 g and of their matched controls was assessed at 8 years of age and the findings were then related to clinical neurologic examination and MRI. Learning disabilities of these children, reported by the teachers, were also studied. Results.u2003The cognitive ability of the preterm children, although in the normal range, was significantly lower than that of the control children. They performed particularly poorly in tasks requiring spatial and visuoperceptual abilities, which were associated with the finding of periventricular leukomalacia in MRI, especially with posterior ventricular enlargement. The preterm children with minor neurodevelopmental dysfunction (MND) had the most problems in neuropsychological tests, whereas the clinically healthy preterm children and those with cerebral palsy had fewer problems. The problems of MND children emerged in the domain of attention. They also experienced the most problems at school. Conclusions.u2003Visuospatial problems were associated with periventricular leukomalacia in MRI, but learning disabilities were most frequent among the preterm children with minor neurologic abnormalities. We recommend closer follow-up of preterm children with MND.

Antigenic Differences between AS03 Adjuvanted Influenza A (H1N1) Pandemic Vaccines: Implications for Pandemrix-Associated Narcolepsy Risk

Background Narcolepsy results from immune-mediated destruction of hypocretin secreting neurons in hypothalamus, however the triggers and disease mechanisms are poorly understood. Vaccine-attributable risk of narcolepsy reported so far with the AS03 adjuvanted H1N1 vaccination Pandemrix has been manifold compared to the AS03 adjuvanted Arepanrix, which contained differently produced H1N1 viral antigen preparation. Hence, antigenic differences and antibody response to these vaccines were investigated. Methods and Findings Increased circulating IgG-antibody levels to Pandemrix H1N1 antigen were found in 47 children with Pandemrix-associated narcolepsy when compared to 57 healthy children vaccinated with Pandemrix. H1N1 antigen of Arepanrix inhibited poorly these antibodies indicating antigenic difference between Arepanrix and Pandemrix. High-resolution gel electrophoresis quantitation and mass spectrometry identification analyses revealed higher amounts of structurally altered viral nucleoprotein (NP) in Pandemrix. Increased antibody levels to hemagglutinin (HA) and NP, particularly to detergent treated NP, was seen in narcolepsy. Higher levels of antibodies to NP were found in children with DQB1*06∶02 risk allele and in DQB1*06∶02 transgenic mice immunized with Pandemrix when compared to controls. Conclusions This work identified 1) higher amounts of structurally altered viral NP in Pandemrix than in Arepanrix, 2) detergent-induced antigenic changes of viral NP, that are recognized by antibodies from children with narcolepsy, and 3) increased antibody response to NP in association of DQB1*06∶02 risk allele of narcolepsy. These findings provide a link between Pandemrix and narcolepsy. Although detailed mechanisms of Pandemrix in narcolepsy remain elusive, our results move the focus from adjuvant(s) onto the H1N1 viral proteins.

Feeding skill milestones of preterm infants born with extremely low birth weight (ELBW)

AIMnTo compare the feeding development of preterm infants with that of full-term infants.nnnPARTICIPANTSnNineteen preterm infants with extremely low birth weight, and 11 healthy full-term infants.nnnMETHODSnIntensive follow-up study. Feeding situations were analyzed by NOMAS (Neonatal Oral Motor Assessment Scale) and by an oral motor patterns checklist based on video recorded sessions.nnnRESULTSnMost of the preterm infants showed a disorganized sucking pattern and most of the full-term infants a normal sucking pattern, as long as suckling was present. However, the early suckling pattern did not predict the schedule of later feeding development. Preterm infants seemed to learn the various feeding skills at the same corrected ages as full-term infants, with the exception of munching, which they learned earlier than the full-term infants. However, the age range for gaining these skills was wider for the preterm infants. Preterm infants also seemed to have feeding problems more often than full-term infants when qualitative features of feeding were considered. Feeding was prolonged and messy, and the preterm infants were sensitive to different qualities of food.nnnCONCLUSIONnFeeding development of preterm and full-term infants is similar except for suckling, when only oral motor skills are concerned. When the qualitative characteristics of feeding are taken into account, the preterm infants suffer from feeding problems that create a risk for early interaction and communication.

Very preterm birth and foetal growth restriction are associated with specific cognitive deficits in children attending mainstream school

This study investigated the association of prenatal and neonatal factors with cognitive outcomes in schoolchildren born very preterm without impairments at the age of nine.

Temporal Changes in Incidence and Prevalence of Intellectual Disability Between Two Birth Cohorts in Northern Finland

We followed two separate, genetically homogeneous cohorts of children born in 1966 (n = 11,965) and 1985-1986 (n = 9,432) in Northern Finland to determine temporal changes in the incidence and prevalence of subcategories of intellectual disability within the same geographic area. The children were followed up to the age of 11.5 years. Similar study design, data ascertainment methods, and definition of intellectual disability were used. There was no change in the total incidence (12.62/1,000 in each) or in total prevalence (11.03/1,000 vs. 11.23/1,000) of intellectual disability. However, in the subcategories of intellectual disability, there was a shift from severe and moderate towards mild; whereas profound intellectual disability remained at the same level. The temporal changes followed generally similar patterns by gender.

Neurocognitive Test Profiles of Extremely Low Birth Weight Five-Year-Old Children Differ According to Neuromotor Status

The neurocognitive outcome of children born with extremely low birth weight (ELBW) is highly variable due to the complexity of morbidity. So far, no study has compared comprehensive neuropsychological test profiles in groups with different neuromotor status. In a national cohort of ELBW children neuropsychological test profiles were assessed in 4 groups defined according to a neurological examination at 5 years of age: normal neuromotor status (N = 56), motor coordination problems (N = 32), multiple subtle neuromotor signs including both motor coordination problems and deviant reflexes (N = 20), and spastic diplegia (N = 12). The neurocognitive assessment included a test of intelligence, the Wechsler Primary and Preschool Scale of Intelligence–Revised (WPPSI–R) and 14 subtests of attention and executive functions, verbal functions, manual motor functions, visuoconstructional functions and verbal learning (NEPSY). The children with normal neuromotor status performed within the average range; children with motor coordination problems had widespread impairment; and children with spastic diplegia and children with multiple minor neuromotor signs had uneven test profiles with stronger verbal results but weaknesses in attention and executive functions, and in manual motor and visuoconstructional tasks. In conclusion, very preterm children with neuromotor signs, including motor coordination problems, are at risk for neurocognitive impairment, in spite of average intelligence. More impaired children have more irregular test profiles. Follow-up and neuropsychological assessment of very preterm children with minor neuromotor signs are therefore indicated.

Etiological survey on intellectual disability in the northern Finland birth cohort 1986.

The etiology of intellectual disability was studied both in incident (n = 9,432) and prevalent (n = 9,351) populations in a one-year birth cohort born in Northern Finland in 1985-1986. Data from multiple sources were used to follow the children until the age of 11.5 years. Of the incident cases (n=119) with intellectual disabilities, 66.4% had etiologically biomedical associative factor. Paranatal factors were relatively fewer and prenatal more common compared with earlier studies. We found nearly double the prevalence of genetic factors leading to intellectual disabilities compared with a contemporary study from Norway. The differences between the populations, despite random variation, some dissimilarities between etiological categorization and diagnostic accuracy, are in most part due to true differences between the study populations and genetic pool.

Perinatal immunoproteins predict the risk of cerebral palsy in preterm children.

Abstract Objective. To investigate whether blood cytokines during the perinatal period predict the risk of cerebral palsy (CP) in preterm infants. Methods. This prospective cohort study comprised 169 children born before 32 weeks of gestation. Cord blood was drawn at birth, and 109 cytokines were analyzed using microarrays. Eleven cytokines were further measured from both cord and peripheral blood on days 1 and 7. Cerebral palsy was confirmed at 5 years of age. Results. Cerebral palsy was diagnosed in 19 children. Five clusters of cord blood cytokines were scored using factor analysis. According to logistic regression analysis, the scores of factors 1 and 2 independently predicted the risk of CP. These cytokines included several growth factors and chemokines, and they all tended to be higher in children with CP than in children without CP. Inflammatory cytokine levels were associated with CP risk on days 1 and 7 after birth. Conclusion. The high blood concentrations of various cytokines during the perinatal period may relate to CP, and these cytokines may influence the pathways leading to early insult in the central nervous system. The risk profile of inflammatory cytokines is different at birth than during the first week after birth.