Valtyr Thors

Background: Antimicrobials have saved millions of lives. Antibiotics are essential in treating infant infections, but may disrupt the gut microbiome and have adverse effects on later health. Methods: This population-based birth cohort study included full-term children born in Iceland from 2010 to 2019 with follow-up for 2–12 years. The cohort was divided into 4 groups according to antibiotic exposure; I: elective cesarean section, II: vaginal birth and maternal intrapartum antibiotics, III: vaginal birth and infants received antibiotics during the first week of life for >48 hours and IV: vaginal birth without antibiotic exposure. Rates of infections, antibiotic use and the risk of asthma later in childhood were calculated. Results: Of 43,600 children born in Iceland from 2010 to 2019, 22,393 were included. Group I had 1496 children, group II 3413, group III 356 and group IV 17,128 children. For all antibiotic exposure groups, the risk of infections and antibiotic use was significantly higher (20%–100%), with the largest effect observed for infants treated with antibiotics. This group also had a 2-fold risk of asthma diagnosis when compared with controls (odds ratio: 1.91, P < 0.05). Conclusions: In this cohort study, children with early antibiotic exposure had higher rates of infections and antibiotic use later in childhood compared with controls. Diagnoses of asthma were significantly more common in children with early antibiotic exposure and this effect was most evident after the age of 8 years. The observed late side-effects of antibiotic use, possibly mediated through a disrupted microbiome, should promote a conservative approach to antibiotic treatment in young infants.

Background: An unprecedented increase in pediatric invasive group A streptococcal (iGAS) infections was observed in most countries, including Iceland, in early 2023. The reasons for this rise are largely unknown. The aim of the study was to describe the parallel between nasopharyngeal (NP) carriage of group A streptococcal (GAS) in Icelandic children and the incidence of invasive disease. Methods: Electronic health records were used to identify children admitted to the Children’s Hospital, Iceland, with iGAS. NP samples from asymptomatic children were collected for culture in February and March 2023 in 15 day-care centers in the greater Reykjavik area. Invasive and noninvasive isolates were characterized using whole genome sequencing. The results of the NP carriage were compared with data from 2009 to 2020. Results: Twenty-one children were diagnosed with iGAS from December 2022 to April 2023. Empyema, necrotizing fasciitis and septic or toxic shock were the most common clinical presentations. All the children were hospitalized; none died, but 9 needed intensive care. Pediatric iGAS infections increased 8-fold from a mean of 2.0/100.000 for 1975 to 2022 to 16.5/100.000 in early 2023. Asymptomatic NP GAS carriage among healthy children increased 3.5-fold from 8.0% from 2009 to 2020 to 28.5% in early 2023. Close genetic relatedness was found between carriage and invasive strains. Conclusions: The significant rise of NP GAS carriage observed in early 2023 likely contributed to the simultaneous increased incidence of iGAS. With surveillance data, microbiological culture and molecular typing, genetic similarities between invasive disease isolates and NP isolates characteristics were confirmed.

Introduction: Inappropriate antibiotic use in infants can have multiple adverse effects and contribute to the development of bacteria resistant to antimicrobials. Antimicrobial stewardship programs can reduce unnecessary antibiotic use in children. The aim of this study was to evaluate the effect of an antimicrobial stewardship program implemented in 2017 in the Neonatal Intensive Care Unit (NICU) at The Children’s Hospital Iceland.Materials and methods: The study included all infants who were admitted to the NICU during the study period (January 1^st 2012–October 31^st 2020). Data was collected from hospital records. Three periods were defined: preimplementation (2012–2014), peri-implementation (2015–2016) and postimplementation (2017–October 2020). Antibiotic use was quantified using days of therapy (DOT) per 1000 bed days (BD). For statistical analysis the pre- and postimplementation periods were compared.Results: Antibiotics were administered in 38.6% (1372) of admissions to the NICU during the study period. Antimicrobial use per year decreased from 584.6 to 317.1 DOT/1000 BD per year (P < 0.001). Use of broad-spectrum antibiotics decreased significantly. The average number of BD per month decreased from 297.8 to 220.9 BD/month (P = 0.0096). There were no significant changes in the length of stay for each infant or the proportion of readmissions or retreatment.Conclusion: Increased awareness of appropriate use of antimicrobials in the NICU led to shorter treatments and less use of broad-spectrum antibiotics. No increase in adverse effects such as readmissions or retreatment was observed.

AimThe survival rate after treatment for childhood leukaemia has greatly improved, but could result in protracted immune deficiency. This study examined the immune status of children after chemotherapy and evaluated their responses to immunisation.MethodsSubjects who had completed their treatment for acute lymphoblastic leukaemia at The Children's Hospital Reykjavik, Iceland, during 2011-2020 had blood drawn and were then immunised for influenza in October 2021. Blood was drawn again 4 weeks later and their humoral and cellular responses were measured with a haemagglutination inhibition assay and lymphocyte stimulation test. Antibodies to other immunisations were also evaluated.ResultsWe studied 18 patients (10 male) who had completed their treatment at 3.7-20.3 years of age (mean 9.1), 11-84 months (mean 36.9) before enrolment. Conventional immunological evaluation did not reveal notable abnormalities. The responses to several childhood vaccinations, including the pneumococcal conjugate vaccination, were adequate in most patients. Humoral responses to the influenza vaccine confirmed adequate reactions in all but one patient. Considerable variations were observed in the lymphocyte stimulations tests.ConclusionMost patients reacted adequately to immunisation, especially against annual influenza and Streptococcus pneumoniae, reiterating the usefulness of vaccinations. The most appropriate timing for vaccination after treatment still needs to be determined.

Purpose: Pediatric severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections are usually mild and the mortality rates are low, but concerns have been raised about long-term symptoms that may resemble other postinfectious syndromes. Studies with robust control groups and high response rates have been few. Methods: We obtained identifiers for all 837 Icelandic children diagnosed with SARS-CoV-2 by PCR between March 2020 and June 2021 and contacted them by telephone. We asked about 10 physical and mental symptoms being present at least twice weekly for at least 2 months. Participants who reported symptoms were contacted again a year later. For each subject who completed the questionnaire, an age- and sex-matched comparator without SARS-CoV-2 infection was asked to complete the same questionnaire, and the risk difference was calculated. Results: Responses from 643 cases and 602 comparators were analyzed. Children who had been infected with SARS-CoV-2 were more likely to report one or more symptoms, except for anxiety/depression and sleep disturbances. Fatigue and loss of concentration were evidently more common in cases among teenagers (risk difference: 15%; 95% CI: 7–22% and 15%; 95% CI: 7–23%, respectively). At the second follow-up, close to a third of Long COVID cases had resolved but some participants had developed new persistent symptoms. Conclusion: Symptoms of Long COVID in children are common and impact their quality of life. The importance of further unraveling the pathophysiology of acute and long-term symptoms following SARS-CoV-2 infection in children is vital as well as potential preventive measures.

Background: Neisseria meningitidis is a commensal bacterium which can cause invasive disease. Colonisation studies are important to guide vaccination strategies. Aim: The study’s aim was to determine the prevalence of meningococcal colonisation, duration of carriage and distribution of genogroups in Iceland. Methods: We collected samples from 1 to 6-year-old children, 15–16-year-old adolescents and 18–20-year-old young adults. Carriers were sampled at regular intervals until the first negative swab. Conventional culture methods and qPCR were applied to detect meningococci and determine the genogroup. Whole genome sequencing was done on groupable meningococci. Results: No meningococci were detected among 460 children, while one of 197 (0.5%) adolescents and 34 of 525 young adults (6.5 %) carried meningococci. Non-groupable meningococci were most common (62/77 isolates from 26/35 carriers), followed by genogroup B (MenB) (12/77 isolates from 6/35 carriers). Genogroup Y was detected in two individuals and genogroup W in one. None carried genogroup C (MenC). The longest duration of carriage was at least 21 months. Serial samples from persistent carriers were closely related in WGS. Conclusions: Carriage of pathogenic meningococci is rare in young Icelanders. Non-groupable meningococci were the most common colonising meningococci in Iceland, followed by MenB. No MenC were found. Whole genome sequencing suggests prolonged carriage of the same strains in persistent carriers.