SARS-CoV-2 seroprevalence among children in Greece during Omicron variant period.

The Omicron variant is associated with increased transmissibility, but evidence about the impact of Omicron in seropositivity of children is limited. This study aims to evaluate SARS-CoV-2 seroprevalence in children during the different variants' subperiods. A prospective multicenter seroprevalence study was conducted in 7 University public hospitals in Greece from November 2021 to August 2022 (3 subperiods: November 2021-February 2022, March 2022-May 2022, June 2022-August 2022). Children from different age groups, admitted to the hospital or examined in outpatient clinics for reasons other than COVID-19 were enrolled. Neutralizing antibodies (Nabs), anti-Spike (anti-S) and anti-nucleocapsid (anti-N) SARS-CoV-2 IgG in serum were evaluated. A total of 2127 children (males:57,2%; median age:4,8years) were enrolled. Anti-N IgG seropositivity increased from 17,8% in the first sub-period to 40,7% in the second sub-period and then decreased in the third sub-period (36,7%). Anti-S IgG seropositivity appeared to have an increasing trend over the study period, starting from 34,8% and reaching 80,7%. Children aged 1-4 years old have significantly higher anti-N IgG titers compared to children aged 0-1 years old (p < 0,001). Infants have significantly lower anti-S IgG titers compared to all other age groups (p < 0,001). Immunocompromised children and infants have the lowest seropositivity for NAbs.Conclusions During the Omicron period, seropositivity significantly increased, as a result of higher transmissibility. Neonates and infants have lower antibody titers compared to other age groups, while young children aged 1-4 years old present higher antibody titers, suggesting that this age group may mount a higher antibody response. Continuous surveillance seroprevalence studies are needed in children, in order to identify the true extent of SARS-CoV-2 and guide the planning of adequate public health measures.

WHAT IS KNOWN: • Seroprevalence surveys among children may be extremely useful, in order to properly monitor the immunity, either natural or acquired, through the quantification of IgG antibodies and to plan further immunization policies. • There are variations in the seroprevalence of COVID-19 between the different periods, according to the vaccination rates, the type of circulating variant and the transmissibility of the virus. • The Omicron variant is associated with increased transmissibility, but evidence about the impact of Omicron in seropositivity of children is limited. WHAT IS NEW: • In this large multicenter seroepidemiological study, SARS-CoV-2 seroprevalence rate in children is higher during the Omicron period in comparison to the previous pandemic waves, due to the high transmissibility of the virus and the increased rates of reinfection. • Neonates and infants have lower antibody titers compared to other age groups, while young children aged 1­4 years old present higher antibody titers, indicating that the children of this age group mount a higher antibody response. • This study provides essential information about immunity and the level of protection in the pediatric population, as neutralizing antibodies were evaluated, in addition to the anti-N and anti-S IgG antibodies.

Parental attitudes towards vaccination against COVID-19 of children 5-11 years old in Greece.

RATIONALE: Vaccinating children against COVID-19 is critical to contain the ongoing pandemic. AIMS/OBJECTIVES: The aim of the present study was to assess parents' and caregivers' intention to vaccinate their 5-11 years old children against COVID-19 and to estimate the association between vaccination intention and sociodemographic, clinical and contextual factors. METHOD: We conducted a questionnaire-based survey on a convenience sample of parents in Patras, Western Greece. RESULTS: Out of 366 study participants, around 48% reported their intention to vaccinate their child. The main factors associated with positive attitudes were paediatrician recommendation, parental vaccination, and reliance on the healthcare providers for decision making. Of note, 80% of the 190 parents who did not intend to vaccinate their children would vaccinate them if the paediatrician recommended it. CONCLUSION: Interventions to further train healthcare professionals to establish rapport with parents, and to provide adequate information about vaccinations are crucial to address concerns related to COVID-19 vaccine benefits for children.

Genetics of primary congenital hypothyroidism-a review.

PURPOSE: Congenital primary hypothyroidism (CH) is a state of inadequate thyroid hormone production detected at birth, caused either by absent, underdeveloped or ectopic thyroid gland (dysgenesis), or by defected thyroid hormone biosynthesis (dyshormonogenesis). A genetic component has been identified in many cases of CH. This review summarizes the clinical and biochemical features of the genetic causes of primary CH. METHODS: A literature review was conducted of gene defects causing congenital hypothyroidism. RESULTS: Mutations in five genes have predominantly been implicated in thyroid dysgenesis (TSHR, FOXE1, NKX2-1, PAX8, and NKX2-5), the primary cause of CH (85%), and mutations in seven genes in thyroid dyshormonogenesis (SLC5A5, TPO, DUOX2, DUOXA2, SLC6A4, Tg, and DEHAL1). These genes encode for proteins that regulate genes expressed during the differentiation of the thyroid, such as TPO and Tg genes, or genes that regulate iodide organification, thyroglobulin synthesis, iodide transport, and iodotyrosine deiodination. Besides thyroid dysgenesis and dyshormonogenesis, additional causes of congenital hypothyroidism, such as iodothyronine transporter defects and resistance to thyroid hormones, have also been associated with genetic mutations. CONCLUSION: The identification of the underlying genetic defects of CH is important for genetic counseling of families with an affected member, for identifying additional clinical characteristics or the risk for thyroid neoplasia and for diagnostic and management purposes.