Background: The "hygiene hypothesis" states that reduced exposure to microbial antigens due to an excessively hygienic environment can increase the risk of developing autoimmune diseases, including atopic disorders and asthma. In recent decades, there has been a progressive decline in the prevalence of numerous microorganisms following improved hygienic-sanitary conditions. More specifically, several studies reported an inverse association between the reduction in Helicobacter pylori infection and the rise of asthma and allergic disorders. Aim: To evaluate the prevalence of atopic disorders in a pediatric population in relation to seropositivity against H. pylori. Methods: Children from Northern Sardinia, Italy, referred to the local Children's Hospital for any reason, were investigated to identify risk factors, especially H. pylori infection, associated with atopic disorders. A validated questionnaire, including demographics, house size, history of breastfeeding, residence, school or daycare center attendance, exposure to animals, and a defined diagnosis of atopy-including asthma-was filled out by a trained pediatrician according to parents' answers and child records. A blood sample was collected from each participant and immunoglobulin G against H. pylori was assessed by a locally validated ELISA test. Results: The seroprevalence of H. pylori infection was 11.7% among 492 children (240 females). Thirty-two children had a confirmed diagnosis of asthma and 12 of allergy. No one child showed both conditions. Statistically significant differences in H. pylori seropositivity were not detected between children with or without atopy (8.4% vs. 12.6; p = 0.233). Although atopic disorders were more frequent in children exposed to traditional atopic risk factors, none of them showed to be significant after adjusting for all covariates. Conclusions: Serologically assessed H. pylori infection was not significantly associated with a reduced risk of atopic diseases in children.

Aims: The primary objectives were to investigate the incidence rate (IR) of type 1 diabetes (T1D) in Sardinian children aged 0-14 years in 2019-2022 and to examine the temporal trend from 1989-1999. Methods: Data from new -onset T1D patients aged 0-14 years who were residents of Sardinia were collected from all pediatric diabetology clinics. The overall, sex- and age specific (groups 0-4, 5-9, and 10-14 years), and calendar year IRs were calculated. The standardized IR (SIR) was also calculated using the direct method. Poisson regression was used to estimate the temporal trend in the SIRs from 1989-1999 to 2019-2022. Results: In 2019-2022, 512 patients aged 0-14 years were diagnosed with T1D in Sardinia. The overall IR was 73.9 per 100,000 person -years (95 % CI 67.6-80.0). Since 1989, the SIR has increased by 2.3 % per year (CI 1.7-2.8, p < 0.0001). The frequency of ketoacidosis at onset was 26.4 %, with no significant differences among the four years. Conclusions: The incidence of T1D in Sardinia, unlike in other countries such as Finland, has almost doubled in the last 20 years, and currently, it appears to be the highest in the world.

Systemic rheumatic diseases, including conditions such as rheumatoid arthritis, Sjögren’s syndrome, systemic sclerosis, and systemic lupus erythematosus, represent a complex array of autoimmune disorders characterized by chronic inflammation and diverse clinical manifestations. This study focuses on unraveling the genetic underpinnings of these diseases by examining polymorphisms in key genes related to their pathology. Utilizing a comprehensive genetic analysis, we have documented the involvement of these genetic variations in the pathogenesis of rheumatic diseases. Our study has identified several key polymorphisms with notable implications in rheumatic diseases. Polymorphism at chr11_112020916 within the IL-18 gene was prevalent across various conditions with a potential protective effect. Concurrently, the same IL18R1 gene polymorphism located at chr2_103010912, coding for the IL-18 receptor, was observed in most rheumatic conditions, reinforcing its potential protective role. Additionally, a further polymorphism in IL18R1 at chr2_103013408 seems to have a protective influence against the rheumatic diseases under investigation. In the context of emerging genes involved in rheumatic diseases, like PARK2, a significant polymorphism at chr6_161990516 was consistently identified across different conditions, exhibiting protective characteristics in these pathological contexts. The findings underscore the complexity of the genetic landscape in rheumatic autoimmune disorders and pave the way for a deeper understanding of their etiology and the possible development of more targeted and effective therapeutic strategies.

Previous studies have highlighted the potential role of Mycobacterium avium subspecies paratuberculosis (MAP) and human endogenous retrovirus W (HERV-W) in the pathogenesis of type 1 diabetes (T1DM) among Sardinian subjects. To better understand how antibody responses evolve during disease progression, a serological evaluation of IgG antibodies was performed in Sardinian children with T1DM collected at different time-points following the onset of the disease. It is known that anti-PI and anti-insulin (IAA) autoantibodies are the first to appear before the clinical onset of T1DM. In order to investigate the humoral responses, 69 children with T1DM were enrolled in the study, including 25 with new onset, 25 with T1DM at 1–5 years since diagnosis and 19 with T1DM at 6–12 years since diagnosis. Serum samples were tested for the presence of antibodies (Abs) against PI46–61, three MAP epitopes (including MAP 2404c, which has a homologous sequence with PI) and two HERV-W-derived epitopes via indirect enzyme-linked immunosorbent assay (ELISA). The data obtained from the analysis showed significantly higher IgG responses against all peptides detected in the new onset group compared to longer suffering (1–5 and 6–12 years) T1DM patients, also showing a robust correlation between the proinsulin autoantibody and anti-MAP/HERV antibodies, characterized by a progressive decline the first year after onset. Taken together, these findings support the hypothesis that MAP and HERV could act as risk factors for T1DM, suggesting that they may serve as potential biomarkers of disease progression in early-stage T1DM.

Human endogenous retroviruses (HERVs) have been thought of as silent passengers within our genomes, but their reactivation has been linked with several autoimmune diseases, including type 1 diabetes (T1DM). In order to evaluate the potential role of HERVs, in addition to the recognized role of HERV-W, we focused on the debated role of the HERV-K family in T1DM. Therefore, we performed a serological evaluation of IgG antibodies against HERV-K Env epitope (HERV-K Env19–37) in comparison to an important β-cellular autoimmunity biomarker, ZnT8, from plasma samples of Sardinian children at the onset of T1DM, different T1DM groups (1–5 and 6–12 years since diagnosis), and healthy controls (HCs), by an indirect enzyme-linked immunosorbent assay (ELISA). A significant antibody response was observed against HERV-K Env19–37 (p < 0.0001) in T1DM patients compared to HCs, and significantly higher IgG responses were detected in the group at the onset compared to the other T1DM groups and HCs. Unlike the trend of the β-cellular autoimmunity autoantibodies, for HERV-K Env antibodies we observed positive values that persist over time up to 5 years since the onset of T1DM. Our results add new evidence about the presence of antibodies against HERV-K in T1DM, but further investigations are necessary to relate these results with the established role of HERVs, considering the contrasting results for HERV-K.

Aim/Hypothesis:To compare the frequency of diabetic ketoacidosis (DKA) at diagnosis of type 1 diabetes in Italy during the COVID-19 pandemic in 2020 with the frequency of DKA during 2017-2019.Methods:Forty-seven pediatric diabetes centers caring for >90% of young people with diabetes in Italy recruited 4,237 newly diagnosed children with type 1 diabetes between 2017 and 2020 in a longitudinal study. Four subperiods in 2020 were defined based on government-imposed containment measures for COVID-19, and the frequencies of DKA and severe DKA compared with the same periods in 2017-2019.Results:Overall, the frequency of DKA increased from 35.7% (95%CI, 33.5-36.9) in 2017-2019 to 39.6% (95%CI, 36.7-42.4) in 2020 (p=0.008), while the frequency of severe DKA increased from 10.4% in 2017-2019 (95%CI, 9.4-11.5) to 14.2% in 2020 (95%CI, 12.3-16.4, p<0.001). DKA and severe DKA increased during the early pandemic period by 10.4% (p=0.004) and 8% (p=0.002), respectively, and the increase continued throughout 2020. Immigrant background increased and high household income decreased the probability of presenting with DKA (OR: 1.55; 95%CI, 1.24-1.94; p<0.001 and OR: 0.60; 95 CI, 0.41-0.88; p=0.010, respectively).Conclusions/Interpretation:There was an increase in the frequency of DKA and severe DKA in children newly diagnosed with type 1 diabetes during the COVID-19 pandemic in 2020, with no apparent association with the severity of COVID-19 infection severity or containment measures. There has been a silent outbreak of DKA in children during the pandemic, and preventive action is required to prevent this phenomenon in the event of further generalized lockdowns or future outbreaks.

The etiology of T1D remains unknown, although a variety of etiological agents have been proposed as potential candidates to trigger autoimmunity in susceptible individuals. Emerging evidence has indicated that endogenous human retrovirus (HERV) may play a role in the disease etiopathogenesis; although several epigenetic mechanisms keep most HERVs silenced, environmental stimuli such as infections may contribute to the transcriptional reactivation of HERV-Wand thus promote pathological conditions. Previous studies have indicated that also Mycobacterium avium subspecies paratuberculosis (MAP) could be a potential risk factor for T1D, particularly in the Sardinian population. In the present study, the humoral response against HERV-W envelope and MAP-derived peptides was analyzed to investigate their potential role in T1D etiopathogenesis, in a Sardinian population at T1D onset (n = 26), T1D (45) and an age-matched healthy population (n = 45). For the first time, a high serum-prevalence of anti-Map and anti-HERV-W Abs was observed in pediatric patients at onset of T1D compared to T1D patients and healthy controls. Our results support the hypothesis that external infections and internal reactivations are involved in the etiology of T1D, and that HERV-W activation may be induced by infectious agents such as MAP.

Objective The short-term effect (60 days) of Lactobacillus brevis CD2 lozenges vs placebo on variables related to caries and gingivitis in type 1 diabetic children was evaluated. Material and methods Eight diabetics (4–14 years old) were assigned to two groups ( n = 34 subjects each), probiotic lozenges and placebo. Stimulated saliva for microbiological analysis and plaque pH were assessed at baseline ( t 0 ), 30 days ( t 1 ), 60 days ( t 2 ) and in the follow-up period (90 days from baseline, t 3 ). Gingival status was assessed at t 0 , t 2 and t 3 . Two-way ANOVA assessed differences between groups. Results In the probiotic group, Streptococcus mutans bacterial density mean scores dropped from 3.11 ± 1.13 at baseline to 1.82 ± 0.72 ( t 2 ) and to 2.06 ± 0.56 ( t 3 ), while in the placebo group, the scores were 3.09 ± 0.8 ( t 0 ), 2.82 ± 0.47 ( t 2 ) and 3.11 ± 0.43 ( t 3 ) ( p < 0.01). Lowest and maximum pH fall increased in the probiotic group, from 5.37 ± 0.41 at baseline to 5.49 ± 0.24 at t 3 ( p < 0.01) and from 1.20 ± 0.46 to 0.98 ± 0.29 ( p = 0.02). Bleeding score decreased significantly in both groups, showing a statistically significant lower bleeding score at t 2 in the probiotic group (25.6%, 95% CI 21.5–32.7 vs 29.5%, 95% CI 25.2–34.9, p = 0.02). Conclusions Lactobacillus brevis CD2 has shown to improve caries-related risk factors and gingival health in diabetic children. Clinical relevance Lactobacillus brevis CD2 might contribute to improved oral health in type 1 diabetic children.

AIM:To evaluate the caries prevalence and related variables in Type 1 diabetic and non-diabetic children and among the diabetic children according to their metabolic status.METHODS:Sixty-eight diabetic and 136 non-diabetic children, matching by gender and age (4-14 years) were enrolled. The diabetic children were divided: a) 20 children in good metabolic control (Hb1ac≤7.5) and b) 48 children in bad metabolic control (Hb1ac>7.5). Dietary and oral hygiene habits were investigated. Caries status was registered using the International Caries Detection and Assessment System. Oral microflora was analysed using the checkerboard DNA-DNA hybridisation method. Plaque acidogenicity was recorded after a sucrose rinse.RESULTS:Sugared beverage and snack intake was higher in diabetic group compared to non-diabetic group (p = 0.03 and p = 0.04, respectively) and in subjects in bad metabolic control (p = 0.03 and p<0.01, respectively). Oral hygiene habits were similar, except for the use of fluoridated adjuvants, higher in non-diabetic children (p = 0.04). No statistically significant differences were observed regarding caries figures, but a higher number of caries free subjects was found in diabetic subjects in good metabolic control (p<0.01). Significant difference for the main cariogenic bacteria was found between diabetic and non-diabetic subjects (p<0.05). The pH values showed statistically significant differences between diabetic and non-diabetic subjects and between diabetic subjects in good and bad metabolic control (p<0.01).CONCLUSIONS:Diabetic children in good metabolic control might even be considered at low caries risk, while those in bad metabolic control showed an oral environment prone to a high caries risk.

Actual caries figures emphasize the need to identify the risk indicators involved in the disease’s development. The hypothesis that certain risk indicators might affect the dynamic evolution of the caries process was assessed; to clarify this premise, a cross-sectional survey was performed in school children.

This longitudinal population-based study analyses the frequency of diabetic ketoacidosis (DKA) at type 1 diabetes diagnosis in Italian children under 15 years of age, during 2004–2013. DKA was defined as absent (pH ≥ 7.30), mild/moderate (7.1 ≤ pH < 7.30) and severe (pH < 7.1). Two multiple logistic regression models were used to evaluate the time trend of DKA frequency considered as present versus absent and severe versus absent, adjusted for gender, age group and geographical area of residence at diagnosis. Overall, 9,040 cases were ascertained. DKA frequency was 40.3% (95%CI: 39.3–41.4%), with 29.1% and 11.2% for mild/moderate and severe DKA, respectively. Severe DKA increased significantly during the period (OR = 1.03, 95%CI: 1.003–1.05). Younger-age children and children living in Southern Italy compared to Central Italy were at significantly higher risk of DKA and severe DKA. Family history of type 1 diabetes and residence in Sardinia compared to Central Italy were significantly associated with a lower probability of DKA and severe DKA. The high frequency of ketoacidosis in Italy over time and high variability among age groups and geographical area of residence, strongly suggests a continuing need for nationwide healthcare strategies to increase awareness of early detection of diabetes.

BACKGROUND:Celiac disease (CD) in children may occur with a wide spectrum of clinical manifestations: anemia is the most frequent extraintestinal manifestation, iron deficiency anemia (IDA) is the common presentation. In our study we aimed to assess IDA condition in a large cohort of pediatric patients with newly diagnosed CD.METHODS:Our study includes a cohort of 518 children (340 females and 178 males), 6 months-18 years old, joined between January 1990 and January 2013. We have analyzed hematological parameters and iron balance: serum iron, serum ferritin and serum transferrin levels. The diagnosis of IDA was considered on the basis of hemoglobin levels below -2SD, associated with serum iron and ferritin reduction, serum transferrin increase; all compared with the normal reference values for age.RESULTS:Of all patients, 156 patients (30.1%) had anemia, including 103 females (19.8%) and 53 males (10.2%); of these, 112 (21.62%) had IDA (in 18 cases associated with α- or β-thalassemia trait), 22 were thalassemic trait without iron deficiency and the remaining 19 suffered from other forms of anemia. One hundred fifteen patients (22.20%) with low ferritin levels but normal hemoglobin levels were considered as preanemic iron deficient patients.CONCLUSION:Our data confirm that iron depletion and IDA represent a frequent finding at the diagnosis of CD. This significant relation existing between CD and iron deficiency should be considered by pediatricians at the diagnosis of CD in order to treat the patients.

ObjectivesAdenosine Deaminase (ADA) contributes to the regulation of adenosine concentration and in turn to T cell activation. Genetic variability of ADA activity may have, therefore, an important role in resistance to malaria. Indeed, previous studies in Sardinia have shown a lower frequency of ADA1*2 allele (associated with low ADA activity) in areas, where malaria was heavily endemic compared to areas where malaria was not endemic. We have now studied the ADA2 locus, another polymorphic site with two alleles ADA2 *1 and ADA2 *2 within the ADA gene.MethodsIn the area of Oristano (where malaria was endemic in the past) 51 consecutive newborns and in the area of Nuoro (where malaria was not as endemic) 48 consecutive newborns were examined.ADA1 and ADA2 genotypes were determined by DNA analysis.ResultsThe low frequency of the ADA1*2 allele in the area where malaria was endemic is confirmed. The frequency of the ADA2*2 allele is higher in Oristano than in Nuoro resulting in a higher frequency of the ADA1*1/ADA2*2 haplotype in Oristano as compared to Nuoro. This suggests a selective advantage of this haplotype in a malarial environment.ConclusionsThe ADA gene shows other polymorphic sites further studies on their role in human adaptation to malaria could be rewarding. Am. J. Hum. Biol. 26:716–718, 2014. © 2014 Wiley Periodicals, Inc.

AIM To investigate the role of protein tyrosin phosphatase 22 (PTPN22), maternal age at conception and sex on susceptibility and age at onset of type 1 diabetes (T1D) in Continental Italy and Sardinian populations. METHODS Three hundred seventy six subjects admitted consecutively to the hospital for T1D and 1032 healthy subjects as controls were studied in Continental Italy and 284 subjects admitted consecutively to the hospital for T1D and 5460 healthy newborns were studied in Sardinia. PTPN22 genotype was determined by DNA analysis. Maternal age at conception and age at onset of disease were obtained from clinical records. χ(2) test of independence, student t test for differences between means and odds ratio analysis were carried out by SPSS programs. Three way contingency table analysis was carried out according to Sokal and Rohlf. RESULTS The pattern of association between PTPN22 and T1D is similar in Continental Italy and Sardinia: the proportion of *T allele carriers is 13.6% in T1D vs 6.7% in controls in Continental Italy while in Sardinia is 7.3% in T1D vs 4.4% in controls. The association between T1D and maternal age at conception is much stronger in Sardinia than in Italy: the proportion of newborn from mother aging more than 32 years is 89.3% in T1D vs 32.7% in consecutive newborn in Sardinia (P < 10(-6)) while in Continental Italy is 32.2% in T1D vs 19.1% in consecutive newborns (P = 0.005). This points to an important role of ethnicity. A slight prevalence of T1D males on T1D females is observed both in Continental Italy and Sardinia. PTPN22 genotype does not exert significant effect on the age at onset neither in Continental Italy nor and Sardinia. Maternal age does not influence significantly age at onset in Italy (8.2 years in T1D infants from mothers aging 32 years or less vs 7.89 years in T1D infants from mothers aging more than 32 years: P = 0.824) while in Sardinia a border line effect is observed (5.75 years in T1D infants from mothers aging 32 years or less vs 7.54 years in T1D infants from mothers aging more than 32 years: P = 0.062). No effect of sex on age at onset is observed in Continental Italy while in Sardinia female show a lower age at onset of T1D as compared to males (8.07 years in males vs 6.3 years in females: P = 0.002). CONCLUSION The present data confirm the importance of ethnicity on susceptibility and on the age at onset of T1D.

Background: It has been suggested that Helicobacter pylori infection might reduce the risk of atopic conditions, such as asthma, in childhood. This risk reduction could relate to the hygiene hypothesis which proposes an association between childhood exposure to microbes and risk of atopy.Objectives: To examine the association between Hp infection and childhood acquired asthma in Sardinia.Patients and Methods: Children from Northern Sardinia who were between the ages of 10 months to 6 years and were screened for Hp infection in 1994-1995 using IgG serology, were asked in 2012, whether they had developed asthma and/or allergic disease in pediatric age, using the global initiative on asthma guidelines questionnaire.Results: A total of 64 children participated in the study. The sero-positivity for Hp infection was 14.1%. Eleven (17.2%) children had a confirmed diagnosis of asthma with onset before the age of 5 years, 85.9% were Hp negative and 14.1% Hp positive. Eight children of the 53 without asthma were Hp positive (15%) compare to one children positive for the infection of the 11 patients (0.09%) with asthma (8/53 vs. 1/11; P = 0.6). The majority of children (73%) were from urban areas and 43.8% had a family history of asthma or allergies. Multiple logistic regression analysis was not able to find a studied variable, including Hp infection, significantly associated with pediatric asthma.Conclusions: Our results speak against Hp infection itself playing a role to protect from the risk to develop childhood asthma although household hygiene was not directly assessed.

Infection of liver cells is the first stage of malaria: parasites replicate inside the cells and then invade erythrocytes. Apoptosis mechanism in liver cells is triggered by the growth of parasites: this provides a release of parasite antigen that initiates a protective immune response. On the other hand, the parasite interferes with cell apoptosis mechanism resulting in resistance to apoptosis and successful infection [1-3]. Recently it has been observed that p53 pathway is involved in parasite survival, increased level of p53 reduces the liver parasite load whereas p53 knockout mice suffers increased liver load [4]. The p53 codon 72 is characterized by a polymorphism in exon 4 with CGC to CCC transition (rs1042522) that confers a change of arginine to proline in amino acid sequence of protein [5]. Amino acid change affects biochemical and functional properties of p53 protein. The arginine variant is a stronger apoptosis inducer while the proline variant is a stronger transcriptional activator [6]. Since apoptosis of liver cells seems to have a protective effect against malaria one would expect a positive selection of *Arg allele in areas of heavy malaria endemia. We have studied 46 consecutive newborn infants from Oristano area of Sardinia and 47 cosecutive newborn infants from area of Nuoro. Oristano was in the past a heavy malaria endemic area whereas the endemia was very light in Nuoro area. Blood was collected from the placental side of umbilical vein after cord section. Written informed consent was obtained by parents to participate to the study that was approved by I.R.B. p53 codon 72 genotypes were determined by DNA analysis as previously described [7]. Figure 1 shows the proportion of p53 codon 72 genotypes in Nuoro and Oristano areas: *Arg/*Arg genotype is much more frequent in Oristano than in Nuoro (p=0.024). The frequency of *Arg allele is 82.6% in Oristano and 69.1% in Nuoro (p=0.04). In accordance with experimental studies suggesting apoptosis of the liver cells as a defense mechanism against parasite invasion, *Arg allele favoring apoptosis seems to have been selected positively in area of Sardinia exposed in the past to heavy malaria endemia.

BACKGROUND:Adenosine deaminase is a polymorphic enzyme that has an important role in immune functions and in the regulation of intracellular and extracellular concentrations of adenosine and adenosine receptor activity.AIM:To search for possible association of type 1 diabetes mellitus (DM1) with three loci haplotypes (ADA1, ADA2, ADA6) of the adenosine deaminase gene.PATIENTS:One hundred and eighty-nine consecutive children with DM1 from Sassari, Sardinia, and a control sample of 239 children from the same area were studied.METHODS:ADA loci genotypes were determined by DNA analysis.RESULTS:Compared to controls, diabetic boys show a decrease of the 2(2)/6(1) haplotype while diabetic girls show an increase of the same haplotype. This association was replicated in an independent sample from Continental Italy.CONCLUSIONS:The 2(2)/6(1) haplotype may exert a protective action in males but may increase susceptibility to DM1 in females: OR = 0.398, 95% CI 0.16-0.96 for males, and OR = 2.31, 95% CI 1.32-4.06 for females.

OBJECTIVE:Genetic differences in the activity of phosphotyrosine phosphatases between mother and embryo could result in a differential activation of signals induced by growth factors in the two sides of placenta. Previous observations suggest that this may have important effects on intrauterine development and survival. The aim of the present study is to confirm previous observations and show new data.STUDY DESIGN:We have studied 573 mother/newborn pairs, 169 wife/husband couples with repeated spontaneous abortion and 34 fertile wife/husband couplesRESULTS:In mother/newborn pairs, the analysis of joint mother/infant ACP1 distribution has shown a deficit of pairs with the mother having low ACP1 S isoform concentration and the infant having high S isoform concentration, and an excess of pairs with the mother having high S isoform concentration and the infant having low S isoform concentration. In RSA couples there is an excess of couples in which the wife has low S isoform concentration and the husband has high S isoform concentration and a deficit of couples in which the wife has high S isoform concentration and the husband has low S isoform concentration. In fertile couples the pattern is reversed.CONCLUSION:The data suggest that when the mother to fetus S isoform concentration ratio is in favour of the mother, the probability of survival of the fetus is greater than in the opposite situation.

Vaccination against the hepatitis A virus (HAV) administered in two doses has been used effectively in universal child immunization programs in several countries. A single-dose vaccination was adopted in some low-income countries in an attempt to reduce costs without losing effectiveness. In 2014, single-dose universal vaccination was introduced in Brazil for children aged two years. Since such strategy is still not universally accepted, its efficacy should be compared to the two-dose strategy. To assess the humoral response after the single-dose HAV vaccination schedule, a cross-sectional study was conducted in Primavera do Leste, in Mato Grosso state, Central Brazil, including 265 children vaccinated through the National Immunization Program. Blood was collected by using a digital puncture and further applied to filter paper cards. Anti-HAV was detected in 218 out of 265 dried blood spots (DBS). Blood venous samples were collected from 34 out of 47 children who were not anti-HAV positive in DBS samples. Eighteen of them tested positive for anti-HAV, giving a final score of 93.6% (236/252) of seropositivity. In conclusion, this study demonstrated a high rate of anti-HAV positivity in the short term after single-dose hepatitis A vaccination in the population investigated. Moreover, the DBS was shown to be a reliable tool for detecting anti-HAV antibodies.