Seroprevalence kinetics of SARS-CoV-2 antibodies in pediatric patients visiting a hospital during COVID-19 pandemic in Japan.

Children infected with SARS-CoV-2 are often asymptomatic or have mild symptoms. The studies on the seroprevalence kinetics of SARS-CoV-2 antibodies in children are limited. We conducted a cross-sectional survey of the positive rate of the SARS-CoV-2 IgG in pediatric patients without suspected COVID-19 infection between January 2007 and March 2022. We defined the serum samples from the pre-pandemic and pandemic groups (1st-6th waves). Totally, 2557 samples were collected and no samples from the pre-pandemic group or the 1st-4th waves were positive for IgG. There were 4/661 and 16/373 positives at the 5th and 6th waves, respectively. At the 5th wave, the prevalence of IgG was 1.3% in children aged 1-4 years. At the 6th wave, in children <1 year of age, the prevalence was 4.0%, and 2.4%, 5.3%, 5.2% and 10% in age groups 1-4, 5-9, 10-14 and 15-18 years, respectively. In conclusions, the pre-pandemic samples were negative, and the IgG positivity increased during the later period of the pandemic.

Anaphylaxis and onsite treatment in schools, kindergartens, and nurseries.

BACKGROUND: There have been no reports on both anaphylaxis incidence rate in schools, kindergarten, and nurseries, or how teachers have treated these children. This study was a fact-finding survey aimed at determining if appropriate responses to anaphylaxis onset were implemented in Oita Prefecture, Japan. METHODS: The Oita Prefectural Allergy Control Committee administered a questionnaire using Google forms to all public and private schools, public and private kindergartens, certified child-care facilities, and day-care centers in the prefecture. RESULTS: Responses to the questionnaire were obtained from 597 institutions, of which 125 890 children were affiliated with the responding institutions. Forty-eight children developed symptoms for which an adrenaline auto-injector was recommended in an Oita guideline. Among these children, three used the adrenaline auto-injector, three were prescribed the adrenaline auto-injector but were unable to use it, 27 were unable to use it as they were not prescribed an adrenaline auto-injector, and the final 15 responded that they handled their symptoms via another method because none of the above options apply. CONCLUSIONS: Most children who developed symptoms which an adrenaline auto-injector was recommended had no prescription for an adrenaline auto-injector. There is thus a need for appropriate response training to anaphylaxis whether or not an adrenaline auto-injector was prescribed.

[A CASE OF ORAL MITE ANPHYLAXIS IN WHICH BASOPHIL ACTIVATION TEST WAS USEFUL FOR DIAGNOSIS].

We treated a 13-year-old girl who developed dyspnea after ingestion of okonomiyaki, a Japanese savory pancake prepared from takoyaki flour mix that was opened several months ago and had been stored at ambient temperature. She was found to be sensitized to mite antigen, and microscopic examination of the flour specimen revealed contamination with mites. Therefore, she was diagnosed with oral mite anaphylaxis (OMA). For a more definitive diagnosis, we performed the basophil activation test (BAT) not only in this patient but also in a healthy woman who was not sensitized to mite (control), using the mite-contaminated flour and unopened takoyaki flour mix as antigens. The objective was to rule out the possibility of non-specific basophil activation induced by takoyaki flour mix. A strong activation of the patient's basophils was observed on stimulation with mite-contaminated flour, whereas no reaction was observed on stimulation with flour from the unopened pack. In the healthy control, no reaction was observed on stimulation with either of the flour samples. We demonstrate that BAT may be a useful substitute to the oral food challenge test for the auxiliary diagnosis of OMA.

A New Era in Diagnostic Ultrasound, Superb Microvascular Imaging: Preliminary Results in Pediatric Hepato-Gastrointestinal Disorders.

Introduction Superb microvascular imaging is a new ultrasound image processing technique that uses advanced clutter suppression to extract flow signals from vessels and which helps us visualize very small vascular structures that were not previously visible without the use of a contrast agent. We herein analyzed the usefulness of superb microvascular imaging in the diagnosis of hepato-gastrointestinal disorders in pediatric patients. Materials and Methods Fifty-six pediatric patients who underwent a total of 81 superb microvascular imaging examinations with an Aplio 300 ultrasound system (Toshiba Medical Systems, Tokyo, Japan) were enrolled in this study. The subjects underwent conventional ultrasound examinations, including Doppler imaging followed by superb microvascular imaging. The superb microvascular imaging findings and standard imaging were compared. All of the examinations were performed without sedation. Results The average age of the patients (male, n = 38; female, n = 18) was 4 years. The clinical diagnoses included hepatobiliary disorders (n = 29), acute appendicitis (n = 10), and other intestinal disorders (n = 17). The target organs for superb microvascular imaging were the liver, appendix, rectum, intestine, gallbladder, and lymph node. In most of the patients, superb microvascular imaging achieved the excellent visualization of microvascular structures, revealing abnormal vasculature in 21 out of 46 (45.7%) examinations of the liver, 9/9 (100%) examinations of the appendix, 0/11 (0%) examinations of the rectum, 9/11 (81.8%) examinations of the intestine, 0/1 (0%) examinations of the gallbladder, and 3/3 (100%) examinations of the lymph nodes. Superb microvascular imaging was superior to Doppler imaging for depicting the microvascular structures. Conclusions Superb microvascular imaging is especially useful for depicting the microvascular flow and can aid in the diagnosis and treatment planning for pediatric patients with hepato-gastrointestinal disorders.