Season of birth is associated with increased risk of atopic dermatitis in Japanese infants: a retrospective cohort study.

BACKGROUND: Several epidemiological studies have examined the possibility of a relationship between season of birth and atopic dermatitis (AD) and food allergy (FA), yet their results are contradictory. We investigated the association between season of birth and risk of AD and FA in Japanese infants. METHODS: Study subjects were 612 newborn infants born at a single obstetric/pediatric clinic without perinatal diseases. Season of birth was classified as spring (March-May), summer (June-August), autumn (September-November) or winter (December-February). AD was diagnosed according to the United Kingdom Working Party's criteria. FA was defined as present if there was a history of immediate allergic symptoms within 2 h after ingestion of a food. Specific IgE to the corresponding food was also assessed to support the diagnosis. We assessed the association between season of birth and risk of AD and FA using Cox proportional hazard models. RESULTS: We identified a total of 365 cases of AD occurring during 3659 person-months of follow-up. Compared with summer birth, autumn, winter, and spring birth were significantly positively associated with the risk of AD: adjusted HRs (95% CIs) were 2.67 (1.96-3.63), 1.42 (1.03-1.95), and 1.43 (1.04-1.98), respectively. We identified a total of 23 cases of physician-diagnosed FA occurring during 6815 person-months of follow-up. CONCLUSIONS: Being born in the summer is associated with a lower risk of AD compared to other seasons of birth. The low incidence of FA in our cohort group made it difficult to establish a valid association between FA and season of birth as the statistical power was low.

[A study on the HA amount of HA influenza vaccination on efficacy and safety in infants].

We examined the efficacy and safety of inactivated influenza vaccine when the amount of HA influenza vaccination in children was increased to the dose recommended by the WHO. The purpose of this study was to obtain basic evidence to review the vaccination dose in Japanese children. HA influenza vaccine produced by the Research Foundation for Microbial Diseases of Osaka University (Biken) licenced in Japan was administered through vaccination at the international dose, and split HA influenza vaccine produced by Sanofi Pasteur corp. (Sanofi) was used as control. Children from 6 months to less than 13 years of age were registered, and vaccinated with doses of 0.25 mL or 0.5 mL. Clinical symptoms during the influenza season were monitored to investigate vaccine efficacy, and information on adverse reactions was collected to evaluate safety profile. Paired serum HI and NT antibody titers were measured at pre first dose and post second dose of vaccination. Both HI and NT antibody titers for H1N1 subtype were satisfactory elevated after administration of both vaccines. Elevation of the NT antibody titer for the H3N2 subtype was observed for both vaccines, but the H3N2 HI antibody titer for the Biken vaccine was not so high. For the subtype B virus, the NT titer had a better response than the HI titer for both vaccines. As only the H1N1 virus was prevalent in the area during the study period, we performed factor analysis concerning influenza contraction only for the H1N1 antibody titer. An HI titer of 1 : 40 or more at post-vaccination was a significant factor to lower the risk of influenza contraction. The relative risk for fever among children with an HI titer of 1 : 20 or less was significantly higher than those with an HI titer of 1 : 40 or more. Children with a higher HI titer had better prevention against fever, so that both vaccines were considered to be effective. As for the appearance of adverse reactions, both vaccines were considered to be safe. From the above-mentioned results, vaccination with the Japanese Biken vaccine at an international dose was thought to be an effective and safe procedure.

Quantitative detection of HCMV-DNA in saliva from infants and breast milk on real-time polymerase chain reaction.

BACKGROUND: The role of breast milk in viral transmission has not been fully studied. To determine the effect of breast milk on the establishment of primary human cytomegalovirus (HCMV) infection in term infants, HCMV-DNA was measured in breast milk and infant saliva. METHODS: The study population consisted of 48 healthy term infants and their mothers. The copy number of HCMV-DNA in the infants' saliva and mothers' milk was measured on quantitative real-time polymerase chain reaction (PCR). RESULTS: HCMV-DNA was detected in both saliva and breast milk from 21 infant-mother pairs, in milk only from four pairs, in saliva only from 12 pairs, and in neither from 11 pairs. HCMV-DNA was first detected in the saliva of 10 infants at age 4 months, seven infants at 7 months, 13 infants at 10 months, and three infants at 12 months. The viral loads peaked 4-10 months after birth, and thereafter decreased or became negative. The peak copy number and rate of HCMV-DNA detection in saliva were significantly related to peak copy number and rate of detection in the corresponding breast milk. CONCLUSION: Thus, HCMV passed through breast milk 1-7 months after delivery affects the persistence and level of HCMV-DNA in infant saliva and is the most important route of primary infection.