Increased incidence and clinical picture of childhood narcolepsy following the 2009 H1N1 pandemic vaccination campaign in Finland.

BACKGROUND: Narcolepsy is a rare neurological sleep disorder especially in children who are younger than 10 years. In the beginning of 2010, an exceptionally large number of Finnish children suffered from an abrupt onset of excessive daytime sleepiness (EDS) and cataplexy. Therefore, we carried out a systematic analysis of the incidence of narcolepsy in Finland between the years 2002-2010. METHODS: All Finnish hospitals and sleep clinics were contacted to find out the incidence of narcolepsy in 2010. The national hospital discharge register from 2002 to 2009 was used as a reference. FINDINGS: Altogether 335 cases (all ages) of narcolepsy were diagnosed in Finland during 2002-2009 giving an annual incidence of 0.79 per 100,000 inhabitants (95% confidence interval 0.62-0.96). The average annual incidence among subjects under 17 years of age was 0.31 (0.12-0.51) per 100,000 inhabitants. In 2010, 54 children under age 17 were diagnosed with narcolepsy (5.3/100,000; 17-fold increase). Among adults ≥20 years of age the incidence rate in 2010 was 0.87/100,000, which equals that in 2002-2009. Thirty-four of the 54 children were HLA-typed, and they were all positive for narcolepsy risk allele DQB1*0602/DRB1*15. 50/54 children had received Pandemrix vaccination 0 to 242 days (median 42) before onset. All 50 had EDS with abnormal multiple sleep latency test (sleep latency <8 min and ≥2 sleep onset REM periods). The symptoms started abruptly. Forty-seven (94%) had cataplexy, which started at the same time or soon after the onset of EDS. Psychiatric symptoms were common. Otherwise the clinical picture was similar to that described in childhood narcolepsy. INTERPRETATION: A sudden increase in the incidence of abrupt childhood narcolepsy was observed in Finland in 2010. We consider it likely that Pandemrix vaccination contributed, perhaps together with other environmental factors, to this increase in genetically susceptible children.

Childhood malnutrition and its predictors in rural Malawi.

We prospectively followed up a population-based cohort of 767 rural Malawian children from birth to 36 months to characterise the timing and predictors of malnutrition. Underweight and wasting incidence peaked between 6 and 18 months of age, whereas stunting incidence was highest during the first 6 months of age. After infancy about 40% of the children were underweight, 70% stunted, and about 4% wasted. Small size during the first 3 months of life predicted the incidence of severe underweight (relative risk [95% confidence interval], 1.8 [0.9, 3.4]), severe stunting ( 2.1 [1.3, 3.4]), and moderate wasting (2.0 [1.1, 3.5]). Children with many illness episodes in infancy had a twofold risk for the development of severe underweight and moderate wasting. Severe underweight was further predicted by residence far away from a health facility and moderate wasting by maternal HIV infection. Our conclusion is that the intrauterine period and first 6 months of life are critical for the development of stunting whereas the subsequent year is more critical for the development of underweight and wasting. Strategies combating intrauterine growth retardation, maternal HIV and infant morbidity are likely to reduce the burden of malnutrition in this population.