Long-term prognosis of vaccine-induced contact allergy to aluminium: Third patch-test with additional test preparations.

BACKGROUND: A high incidence of local itching subcutaneous nodules and aluminium allergy was observed in clinical trials of a new aluminium adsorbed pertussis vaccine in Gothenburg, Sweden, in the 1990s. A total of 495 children with itching nodules were patch tested with aluminium chloride hexahydrate 2% and an empty Finn Chamber®, 377 (76%) with positive reactions. When 241 of them were re-tested some years later 186 (3 out of 4) had unexpectedly lost their patch test reactivity. AIM: To investigate the long-term prognosis of vaccine-induced contact allergy to aluminium by a third patch test about 20 years after Patch test I. METHODS: Twenty individuals with positive and 11 with negative results in Patch test II were tested a third time with the same sensitisers as in in the first two tests. Three additional aluminium preparations were also tested. RESULTS: A total 15 out of 20 persons with positive results in the second test had lost their patch test reactivity. Two of 11 with negative tests had turned positive again. The addition of the preparations gave no conclusive results. CONCLUSION: Contact allergy to aluminium caused by vaccination with aluminium-adsorbed vaccines in childhood seems to fade away with time as measured by loss of patch test reactivity.

Pneumococcal concentration and serotype distribution in preschool children with radiologically confirmed pneumonia compared to healthy controls prior to introduction of pneumococcal vaccination in Zanzibar: an observational study.

BACKGROUND: The World Health Organization recommends pneumococcal vaccination (PCV) in the first year of life. We investigated pneumococcal serotypes in children with clinical or radiologically confirmed pneumonia and healthy controls prior to PCV13 vaccine introduction in Zanzibar. METHODS: Children (n = 677) with non-severe acute febrile illness aged 2-59 months presenting to a health centre in Zanzibar, Tanzania April-July 2011 were included. Nasopharyngeal swabs collected at enrolment were analysed by real-time PCR to detect and quantify pneumococcal serotypes in patients (n = 648) and in healthy asymptomatic community controls (n = 161). Children with clinical signs of pneumonia according to the Integrated Management of Childhood illness guidelines ("IMCI pneumonia") were subjected to a chest-X-ray. Consolidation on chest X-ray was considered "radiological pneumonia". RESULTS: Pneumococcal DNA was detected in the nasopharynx of 562/809 (69%) children (70% in patients and 64% in healthy controls), with no significant difference in proportions between patients with or without presence of fever, malnutrition, IMCI pneumonia or radiological pneumonia. The mean pneumococcal concentration was similar in children with and without radiological pneumonia (Ct value 26.3 versus 27.0, respectively, p = 0.3115). At least one serotype could be determined in 423 (75%) participants positive for pneumococci of which 33% had multiple serotypes detected. A total of 23 different serotypes were identified. One serotype (19F) was more common in children with fever (86/648, 13%) than in healthy controls (12/161, 7%), (p = 0.043). Logistic regression adjusting for age and gender showed that serotype 9A/V [aOR = 10.9 (CI 2.0-60.0, p = 0.006)] and 14 [aOR = 3.9 (CI 1.4-11.0, p = 0.012)] were associated with radiological pneumonia. The serotypes included in the PCV13 vaccine were found in 376 (89%) of the 423 serotype positive participants. CONCLUSION: The PCV13 vaccine introduced in 2012 targets a great majority of the identified serotypes. Infections with multiple serotypes are common. PCR-determined concentrations of pneumococci in nasopharynx were not associated with radiologically confirmed pneumonia. Trial registration Clinicaltrials.gov (NCT01094431).

Group B streptococcus - a pathogen not restricted to neonates.

Objectives: This was a retropective study of invasive group B streptococcal (GBS) infections isolated from blood, cerebrospinal fluid (CSF), synovial fluid, peritoneal fluid, pleural fluid, pericardial fluid and corpus vitreum in a defined region in southwest Sweden over a 14-year period. Design: Information on all invasive GBS infections was obtained from all four bacteriological laboratories in the region, with data obtained from individual patient records. Results: GBS was isolated from normally sterile body fluids in 1244 samples (579 from females and 665 from males) from 1101 patients. Of these patients, 196 were neonates. The incidence in neonates (0-27 days) was 7.3 per 100 000 live births per year, but there was a significant decrease from 2012 when risk-factor-based intrapartum antibibiotic prophylaxis was implemented. The great majority of neonatal infections were very early-onset infections. The incidence rates in children (28 days to 17 years), adults (18-64 years) and elderly patients (≥ 65 years) were 1.3, 3.6, and 12.9 per 100 000 per year, respectively. The majority of children and adults had severe underlying diseases, but severe infections were also seen in individuals with no risk factors. Conclusions: GBS is an important pathogen in all age groups. Intrapartum antibiotic prophylaxis significantly decreases very early-onset infections.

Long-term clinical course and prognosis of vaccine-related persistent itching nodules (1997-2019): An observational study.

Background: Vaccines adsorbed to aluminium can induce long-lasting intensely itching subcutaneous nodules (granulomas) at the injection site as well as contact allergy to aluminium. In clinical trials of a new acellular pertussis vaccine performed in the 1990s (Gothenburg, Sweden) with 76 000 participants, itching nodules were reported in 745 children. A positive patch test to aluminium was verified in 77% of the tested children with itchy nodules. Aim: To describe the long-term clinical course and prognosis of vaccine-related itching nodules caused by aluminium-containing pediatric vaccines and to estimate the risk for new symptoms after future vaccination with aluminium-containing vaccines. Methods: 745 children with vaccine-related itching nodules were followed by regular interviews/questionnaires for more than 20 years. 723 of them received a booster dose of diphtheria/tetanus vaccine either with or without aluminium adjuvant during the follow-up time. Results: Most study participants (86%) reported a full recovery from their itching nodules after a median duration of 6.6 years. Only a few of the diphtheria/tetanus-booster-vaccinated children (3%) reported mild transient itching and swelling at the new injection site. Conclusion: Vaccine-induced itching granulomas caused by an aluminium-adsorbed acellular pertussis toxoid vaccine seem to disappear over time. Future vaccinations with aluminium-adsorbed vaccines can be performed with little risk for new itching nodules later in life.

Ethnicity, gender and seasonal variations all play a role in vitamin D deficiency.

AIM: (1) To explore the adherence of recommendations of vitamin D supplementation to children aged 0-4 years. (2) To compare serum levels of vitamin D in children and adolescents aged 0-17 years originating from different parts of the world. (3) To compare levels between boys and girls and (4) To determine seasonal variation. METHODS: A review of vitamin D levels in children with parents from different parts of the world was conducted. 2502 children aged 0-17 years were included between 22 January 2004 and 17 May 2021. RESULTS: Fifty-nine of 363 children aged 0-4 years received the recommended vitamin D supplementation. Children from all parts of the world had lower levels of serum 25(OH)D than Swedish children. Girls from the Indian subcontinent, Middle East and Africa had the lowest levels of s-25(OH)D. Seasonal variation with higher levels during the summer was seen in children from Sweden, the rest of Europe, Russia and Latin America. Overall prevalence of vitamin D deficiency (≤25 nmol/L) was 928/2198 (42%) in children not receiving supplementation. Seven children had clinical rickets. CONCLUSION: Adherence of giving children aged 0-4 years the recommended vitamin D supplementation was very low. Vitamin D deficiency is common in immigrant children of all ages in Sweden.

Invasive pneumococcal disease in persons with predisposing factors is dominated by non-vaccine serotypes in Southwest Sweden.

BACKGROUND: The pneumococcal conjugate vaccine PCV7 was introduced in Southwest Sweden in the child vaccination program in 2009, followed by PCV13 in 2010 and PCV10 in 2015. In this retrospective cohort study we assessed the pneumococcal serotype distribution in relation to predisposing factors, clinical manifestations and outcome during seven years after PCV introduction. METHODS: Clinical data from 1278 patients with 1304 episodes of invasive pneumococcal disease (IPD) between January 2009 and December 2015 in Region Västra Götaland, Sweden, were retrospectively collected from medical records. Pneumococcal isolates were serotyped by gel diffusion and/or Quellung reactions performed at the Public Health Agency in Sweden. Associations between serotypes and clinical characteristics were statistically evaluated by use of Fisher's exact test, Mann-Whitney U test and Logistic regression analysis, whereas IPD episodes caused by serotypes over time were analyzed by Mantel-Haenszel chi-square test. RESULTS: With the exception of serotype 3, the prevalence of PCV13 serotypes decreased during the study period, from 76% (n = 157) of all IPD episodes in 2009 to 25% (n = 42) in 2015 (p < 0.001) while non-PCV13 serotypes increased, mainly among patients ≥65 years and in patients with predisposing factors, including cardiovascular disease, pulmonary disease and malignancy (p < 0.001 for all). Patients with predisposing factors, including those with malignancy, immune deficiency or renal disease, were more likely to have IPD caused by a serotype not included in PCV13 rather than a vaccine-included serotype. Serotype 3 was associated with intensive care unit admissions while serotype 1 and 7F caused IPD among healthier and younger patients. PCV13 serotypes were associated with invasive pneumonia, and non-PCV13 serotypes were associated with bacteremia with unknown focus and with manifestations other than pneumonia or meningitis. CONCLUSIONS: Non-PCV13 serotypes caused the majority of IPD cases in Southwest Sweden, especially in patients ≥65 years and in patients with predisposing factors. Serotype 3, included in PCV13, was prevalent and often caused severe disease.

Prevalence of Latent TB and Effectiveness of BCG Vaccination Against Latent Tuberculosis: An Observational Study.

OBJECTIVES: This study aimed to determine the prevalence of latent tuberculosis infection (LTBI) in immigrant children and adolescents (aged 0-17 years) living or recently arriving in Sweden. It also aimed to estimate the effectiveness of Bacillus Calmette-Guérin (BCG) against LTBI in immigrant children coming to Sweden from high-incidence countries, most of them being asylum seekers. LTBI was defined as a positive Quantiferon or a tuberculin skin test (TST) of ≥ 10 mm in small children from whom it was difficult to obtain 3 mL of blood. DESIGN: A typical BCG scar was used as a substitute for written documentation of BCG vaccination. The study comprised 1,404 immigrants aged 0-17 years. The arms and legs of all of them were inspected for a BCG scar, and Quantiferon or TST was performed. The study was a retrospective, observational, comparative cohort study. RESULTS: LTBI was found in 123 of 1,011 (12%) children with a BCG scar and in 116 of 393 (29.5%) without a BCG scar, giving an estimated vaccine effectiveness of 59%. CONCLUSIONS: LTBI was common among the immigrant children (17%). LTBI can progress to active TB and then spread in the immigrant population and to the general population if all immigrant arrivals are not tested and given prophylactic treatment if they have LTBI. The BCG vaccine was found to have a significant effect on LTBI (59%).

Late-onset Neonatal Infections 1997 to 2017 Within a Cohort in Western Sweden-The Last 21 Years of a 43-Year Surveillance.

BACKGROUND: The objective of the study was to assess the epidemiology of late-onset (LO) neonatal invasive infections with surveillance covering 43 years, starting from 1975. METHODS: Observational epidemiologic, retrospective study including a cohort of infants born in western Sweden in 1997-2017, who had a positive blood and cerebral spinal fluid culture between 3 and 120 days of age. A comparison was made of the incidence between 1997-2007 and 2008-2017. Data on LO infections during 3-27 days of life were assessed from 1975. RESULTS: A total of 473 cases of LO infections were registered in 437 patients. The incidence increased from 2.0 to 3.1/1000 live births (LB) between 1997-2007 and 2008-2017 (P < 0.001). The increase in incidence was most pronounced among infants born <28 weeks gestation (from 255 to 398/1000 LB, P < 0.001). The most frequent pathogens were Staphylococcus aureus (25%), coagulase-negative staphylococci (17%), and Escherichia coli (13%). Infections due to group B Streptococci rose from 0.16/1000 LB to 0.33 (P = 0.03). During the whole surveillance period from 1975 to 2017, there were 579 cases between 3 and 27 days of life. Although the incidence increased in 2008-2017 to 1.9/1000 LB after first declining in 1997-2007, the case-fatality rate continued to decline from 27/284 (9.5%) between 1975 and 1996 to 6/182 (3.3%) in 2008 and 2017 (P = 0.01). CONCLUSIONS: The incidence of LO neonatal invasive infections increased during the study period (1997-2017), but the case-fatality rate remained lower than in the previous surveillance period (1975-1996). Further surveillance and interventions with focus on prevention is critical to counteract the increasing incidence among high-risk infants.

Changes in incidence and etiology of early-onset neonatal infections 1997-2017 - a retrospective cohort study in western Sweden.

BACKGROUND: The objective of the study was to evaluate data on early-onset neonatal invasive infections in western Sweden for the period 1997-2017. To identify changes in incidence, etiology and mortality and compare to previous studies from the same area starting from 1975. METHODS: Observational epidemiological, retrospective study on infants 0-6 days of age with a positive culture in blood and/or cerebrospinal fluid between 1997 and 2017. A comparison was made of the incidence between 2008 and 2017 compared to 1997-2007. Changes in the incidence of infections due to Group B streptococci, Staphylococcus aureus and aerobic Gram-negative rods were assessed from 1975. RESULTS: The total incidence, including both recognized pathogens and commensals as causative agents, was 1.1/1000 live births. The incidence declined from 1.4/1000 LB in 1997-2007 to 0.9/1000 LB in 2008-2017 but the case-fatality rate remained unchanged, (8/119 vs 7/90), at 7%. Among the 209 patients identified during 1997-2017 with sepsis or meningitis the most common organisms were Group B streptococci (40%, 84/209), S. aureus (16%, 33/209) and E. coli (9%, 18/209). The incidence of Group B streptococci infections went from 0.9/1000 live births 1987-1996 to 0.45/1000 live births 1997-2017 and all cases were within 72 h. The proportion of extremely preterm infants (< 28 weeks gestation) rose steadily during the study period but there was no rise in infections due to Gram-negative organisms. The spectrum of cultured organisms changed after 72 h as commensal organisms started to emerge. CONCLUSION: There has been a decrease in the incidence of neonatal early-onset infections compared to previous studies in western Sweden. The incidence of GBS infections was not as low as in other reports. Further studies are needed to assess if screening-based intra partum antimicrobial prophylaxis instead of a risk factor-based approach for identifying candidates for intrapartum antimicrobial prophylaxis would be a better option for this study area. KEY NOTES: This study is one of the longest running follow-ups in the world, a follow-up of 43 years of early-onset neonatal infections.The incidence of early-onset GBS infections is higher in Western Sweden compared to other local reports.No difference in the incidence of early-onset GBS depending on the definition of early-onset being within 72 h or 7 days of life.

Age appropriateness of vaccination with recommended childhood vaccines in Sri Lanka.

Vaccination status is conventionally measured by up-to-date coverage. This method does not take in to account whether the vaccines were received at the correct age and interval which is essential for optimal disease protection. Sri Lanka - a lower middle-income country in the Indian Ocean, has previously presented with high vaccination coverage for all childhood vaccines. However, few studies investigating timeliness of vaccinations have until now been carried out in Sri Lanka. Aim: This study was carried out to investigate the individual coverage and age appropriateness of vaccination, in two different demographic settings in Anuradhapura district, Sri Lanka. The study of cross-sectional descriptive design included 633 children born in 2011. Public Health Midwives kept hand-written documentation of the birth and vaccination dates on each child in her geographic area. Vaccination ages were then compared to the timelines of vaccination provided by the Epidemiology Unit of Sri Lanka. The vaccination coverage for all antigens was 97.5% (94.2-99.7%) at age 5-6 years. Timeliness of doses was between 65.0 and 88.6 % (median 80.7%; 65.0-88.6) and significantly lower in the urban population compared to the rural. The present study shows that the vaccine coverage in both urban and rural areas in Sri Lanka was high and that the timeliness predominantly followed national recommendations.

Cost-effectiveness of childhood pneumococcal vaccination program in Ethiopia: results from a quasi-experimental evaluation.

BACKGROUND: Ethiopia was among the 15 countries that, together accounted for 64% of the world's severe episodes of pneumonia among children below the age of 5 in 2011. To reduce this burden, the 10-valent pneumococcal conjugate vaccine (PCV 10) was introduced into the general childhood national immunization program in Ethiopia in 2011. However, there is little evidence on its cost-effectiveness, and the aim of this study was to estimate the cost-effectiveness of the introduction of PCV 10 vaccination in the Ethiopian setting. METHODS: The cost-effectiveness analysis was carried out based on a quasi-experimental evaluation of implementing PCV 10 at the Butajira rural health program site in Ethiopia. The intervention and the control groups consisted 876 and 1010 children, respectively. Using data from program site's surveillance system database as a framework, health outcome and vaccination data were collected from medical records, immunization registration books and reports. Disability- Adjusted Life Year (DALY) was a main health outcome metric complimented by incidence of acute lower respiratory infection/1000-person years. Vaccination and treatment costs were collected by document review and cross-sectional household survey. RESULTS: In the intervention cohort, 626 of 876 (71.5%) children received PCV 10 vaccination. Until the first year of life, the incidence of acute lower respiratory infection was higher in the intervention group. After the first year of life, the incidence rate was 35.2 per 1000-person years in the intervention group compared to 60.4 per 1000-person years in the control group. The incremental cost-effectiveness ratio (ICER) per averted DALY for the intervention group during the total follow-up period was (2013 US$) 394.3 (undiscounted) and 413.8 (discounted). The ICER per averted DALY excluding the first year of life was (2013 US$) 225 (undiscounted) and 292.7 (discounted). CONCLUSION: Compared to the WHO's suggested cost-effectiveness threshold value, the results indicate that the general childhood PCV 10 vaccination was a cost-effective intervention in the Butajira rural health program site.

Patch testing children with aluminium chloride hexahydrate in petrolatum: A review and a recommendation.

BACKGROUND: According to studies on adults, patch testing with aluminium chloride hexahydrate 2% pet. is insufficient to detect aluminium allergy, and a 10% preparation is recommended. Other studies suggest that a 2% preparation is sufficient for testing children. OBJECTIVES: To review three previously published Swedish studies on patch testing children with aluminium chloride hexahydrate 2% pet. PATIENTS/METHODS: Altogether, 601 children with persistent itching subcutaneous nodules (granulomas) induced by aluminium-adsorbed vaccines were patch tested with aluminium chloride hexahydrate 2% pet. and metallic aluminium in (a) a pertussis vaccine trial, (b) clinical practice, and (c) a prospective study. RESULTS: Overall, 459 children had positive reactions to the 2% pet. preparation. Another 10 reacted positively only to metallic aluminium. An extreme positive reaction (+++) was seen in 65% of children aged 1 to 2 years as compared with 22% of children aged 7 years. From 8 years onwards, extreme positive reactions were scarce. CONCLUSIONS: Aluminium chloride hexahydrate 2% pet. is sufficient to trace aluminium allergy in children. Small children are at risk of extreme reactions. We thus suggest that aluminium chloride hexahydrate 10% pet. should not be used routinely in children before the age of 7 to 8 years.

Pathogen Clearance and New Respiratory Tract Infections Among Febrile Children in Zanzibar Investigated With Multitargeting Real-Time Polymerase Chain Reaction on Paired Nasopharyngeal Swab Samples.

BACKGROUND: New molecular methods have revealed frequent and often polymicrobial respiratory infections in children in low-income settings. It is not known whether presence of multiple pathogens is due to prolonged infections or to frequent exposure. The aim of this study was to analyze short-term pathogen clearance from nasopharynx and the rate of new respiratory tract infections in febrile preschool children. METHODS: Children (n = 207) with uncomplicated acute febrile illness 2-59 months of age presenting to a health center in Zanzibar, Tanzania, April-July 2011, were included. Paired nasopharyngeal swab samples, collected at enrolment and after 14 days, were analyzed by multiple real-time polymerase chain reaction for Adenovirus, bocavirus, Bordetella pertussis, Chlamydophila pneumoniae, Coronaviruses, Enterovirus, influenza A and B virus, metapneumovirus, measles virus, Mycoplasma pneumoniae, parainfluenza virus, Parechovirus, respiratory syncytial virus and Rhinovirus. An age-matched and geographically matched healthy control group (n = 166) underwent nasopharyngeal sampling on 1 occasion. RESULTS: At baseline, 157/207 (76%) patients had at least 1 pathogen detected, in total 199 infections. At follow-up (day 14), 162/199 (81%) of these infections were not detected, including >95% of the previously detected infections with Enterovirus, influenza A virus, influenza B virus, metapneumovirus or parainfluenza virus. Still 115 (56%) children were positive for at least 1 pathogen at follow-up, of which 95/115 (83%) were not found at baseline. Detection of influenza B on day 14 was significantly associated with fever during follow-up. CONCLUSION: The results suggest that children with acute febrile illness in Zanzibar rapidly clear respiratory tract infections but frequently acquire new infections within 14 days.

Comparison of reactivity to a metallic disc and 2% aluminium salt in 366 children, and reproducibility over time for 241 young adults with childhood vaccine-related aluminium contact allergy.

BACKGROUND: An aluminium hydroxide-adsorbed pertussis toxoid vaccine was studied in 76 000 children in the 1990s in Gothenburg, Sweden. Long-lasting itchy subcutaneous nodules at the vaccination site were seen in 745 participants. Of 495 children with itchy nodules who were patch tested for aluminium allergy, 377 were positive. In 2007-2008, 241 of the positive children were retested. Only in one third were earlier positive results reproduced. OBJECTIVES: To further describe patch test reactions to different aluminium compounds in children with vaccine-induced aluminium allergy. PATIENTS/METHODS: Positive patch test results for metallic aluminium (empty Finn Chamber) and aluminium chloride hexahydrate 2% petrolatum (pet.) were analysed in 366 children with vaccine-induced persistent itching nodules tested in 1998-2002. Of those, 241 were tested a second time (2007-2008), and the patch test results of the two aluminium preparations were analysed. RESULTS: Patch testing with aluminium chloride hexahydrate 2% pet. is a more sensitive way to diagnose aluminium contact allergy than patch testing with metallic aluminium. A general decrease in the strength of reactions to both aluminium preparations in 241 children tested twice was observed. CONCLUSIONS: Aluminium contact allergy can be diagnosed by patch testing without using metallic aluminium.

Rapid Clearance and Frequent Reinfection With Enteric Pathogens Among Children With Acute Diarrhea in Zanzibar.

Background: Acute infectious gastroenteritis is an important cause of illness and death among children in low-income countries. In addition to rotavirus vaccination, actions to improve nutrition status, sanitation, and water quality are important to reduce enteric infections, which are frequent also among asymptomatic children. The aim of this study was to investigate if the high prevalence of these infections reflects that they often are not cleared properly by the immune response or rather is due to frequent pathogen exposure. Methods: Rectal swabs were collected at time of acute diarrhea and 14 days later from 127 children, aged 2-59 months and living in rural Zanzibar, and were analyzed by real-time polymerase chain reaction targeting multiple pathogens. Results: At baseline, detection rates >20% were found for each of enterotoxigenic Escherichia coli, Shigella, Campylobacter, Cryptosporidium, norovirus GII, and adenovirus. At follow-up, a large proportion of the infections had become cleared (34-100%), or the pathogen load reduced, and this was observed also for agents that were presumably unrelated to diarrhea. Still, the detection frequencies at follow-up were for most agents as high as at baseline, because new infections had been acquired. Neither clearance nor reinfection was associated with moderate malnutrition, which was present in 21% of the children. Conclusions: Children residing in poor socioeconomic conditions, as in Zanzibar, are heavily exposed to enteric pathogens, but capable of rapidly clearing causative and coinfecting pathogens.

[Doxycycline can be given to children without risk of staining of teeth]. / Doxycyklin kan ges till barn i alla åldrar - Ingen risk för missfärgning av tänder eller emaljhypoplasi.

Doxycycline can be given to children without risk of staining of teeth In Sweden, several hundred children are treated for Lyme neuroborreliosis annually, the majority of which are treated with intravenous ceftriaxone. Older tetracycline class antibiotics can cause permanent staining of the teeth. For doxycycline this has never been shown. Three publications on children exposed to doxycycline from three months of age show no risk of staining of the teeth. Changing the recommended treatment for children with Lyme neuroborreliosis to oral doxycycline would markedly simplify treatment for children and parents and reduce healthcare costs.

Neuroborreliosis in Swedish Children: A Population-based Study on Incidence and Clinical Characteristics.

BACKGROUND: Borrelia burgdorferi is a common cause of bacterial meningitis, but there are very few studies on incidence in Europe. The aim of this study was to report the incidence and symptoms of neuroborreliosis in Swedish children. METHODS: Medical records of children (< 15 years) treated for neuroborreliosis 2002-2014 were studied retrospectively. The patients were identified in the computerized registers of discharge diagnoses at the Departments of Pediatrics and Infectious Diseases in Gothenburg, Borås, Trollhättan and Halmstad using International Classification of Diseases 10 diagnosis codes G51.0, G01.9 and/or A69.1. Of those, patients with symptoms compatible with neuroborreliosis and a white blood cell count in cerebrospinal fluid ≥ 7 cells/mm with ≥ 80% mononuclear cells were included. Only children living in the city of Gothenburg and 10 surrounding municipalities were included. RESULTS: Five hundred forty-eight children were included. The median age was 7 (1-14) years. The total incidence for the 13-year-period was 2.8/10,000 and remained unchanged during the period. The incidence was significantly higher in rural (4.0/10,000) than in urban municipalities (2.1/10,000). The most common presenting symptoms were headache (n = 335), fatigue (n = 330) and cranial nerve palsies (n = 329). The median duration of symptoms before admittance was 4.0 days for facial palsy and 14.0 days for other symptoms (P < 0.001). The median white blood cell count in cerebrospinal fluid was 129 (7-1069) cells/mm. CONCLUSIONS: This study is the largest so far in a pediatric population. The incidence of neuroborreliosis was higher than in previous European reports. This might be explained by increased Borrelia awareness, the distribution of tick population in Sweden, and the possibility that Swedish children more frequently play outdoors.