Oropouche fever cases diagnosed in Italy in two epidemiologically non-related travellers from Cuba, late May to early June 2024.

Oropouche fever is caused by Oropouche virus (OROV), transmitted primarily through the bite of infected midges, particularly of the genus Culicoides. The virus is mainly circulating in Central and South America where several countries reported an ongoing outbreak. We report here two imported cases of OROV infection identified in Italy, late May-early June 2024. These cases indicate that in the shadow of a massive dengue outbreak in the Americas, the Oropouche outbreak might be more widespread than previously estimated.

Prosthetic joint infection due to Mycobacterium xenopi: a review of the literature with a new case report.

PURPOSE: Extrapulmonary infections due to M. xenopi, particularly osteoarticular localizations, are rare. The purpose of this paper is to describe a case of prosthetic hip infection and to review the published literature on cases of M. xenopi osteoarticular infections. METHODS: Literature search was performed in the following databases: MEDLINE (PubMed), Embase, Central (the Cochrane Library 2019, Issue 1), LILACS (BIREME) (Latin American and Caribbean Health Science Information database) and Clinical Trials databases (14th August 2018). We included all case reports and case series on adult patients diagnosed with bone or joint infection by M. xenopi for whom the treatment and outcome were specified. RESULTS: We retrieved 30 cases published between 1982 and 2012, among which 25 (83.3%) were reported from Europe. The two most common infection sites were spine (12/30, 40%) and knee (9/30, 30%). Risk factors for infection were previous invasive procedures (11/30, 36.7%), autoimmune disease (8/30, 26.7%), AIDS (4/30, 13.3%) and other comorbidities (2/30, 6.7%); five patients had no past medical history. All patients were treated with antibiotic combinations, but composition and duration of regimens hugely varied. Surgical intervention was performed in 16 patients (53.3%). Only 11 patients obtained full recovery of articular mobility after treatment. CONCLUSION: This work highlights the difficulties in diagnosing and treating M. xenopi osteoarticular infections. Globally, evidence supporting the best practice for diagnosis and treatment of this infection is scanty.

Epidemiology of Strongyloides stercoralis in northern Italy: results of a multicentre case-control study, February 2013 to July 2014.

Strongyloides stercoralis is a soil-transmitted helminth widely diffused in tropical and subtropical regions of the world. Autochthonous cases have been also diagnosed sporadically in areas of temperate climate. We aimed at defining the epidemiology of strongyloidiasis in immigrants and Italians living in three northern Italian Regions. Screening for S. stercoralis infection was done with serology, confirmation tests were a second serological method or stool agar culture. A case-control approach was adopted and patients with a peripheral eosinophil count ≥ 500/mcL were classified as cases. Of 2,701 individuals enrolled here 1,351 were cases and 1,350 controls; 86% were Italians, 48% women. Italians testing positive were in 8% (97/1,137) cases and 1% (13/1,178) controls (adjusted odds ratio (aOR) 8.2; 95% confidence interval (CI): 4.5-14.8), while positive immigrants were in 17% (36/214) cases and in 2% (3/172) controls (aOR 9.6; 95% CI: 2.9-32.4). Factors associated with a higher risk of infection for all study participants were eosinophilia (p < 0.001) and immigration (p = 0.001). Overall, strongyloidiasis was nine-times more frequent in individuals with eosinophilia than in those with normal eosinophil count.

Screening for Neurocognitive Impairment in HIV-Infected Individuals at First Contact after HIV Diagnosis: The Experience of a Large Clinical Center in Northern Italy.

Neurocognitive disorders are emerging, probably underestimated, complications in HIV-infected people. The aim of the study was to assess neurocognitive profiles of newly detected HIV-infected patients. We performed an observational retrospective single-cohort study. Illiterates and patients with neurologic symptoms or previous psychiatric diagnosis were excluded. Neuropsychological profiles were assessed using a validated battery of neuropsychological tests. We included 206 patients; with males representing the majority of them (85%). Risk factors for HIV acquisition were unprotected sexual intercourse (homo/bisexual in 39.8% and heterosexual in 60.2%). Thirty-nine patients (18.9%) were previous injection drug users, while 41 (19.9%) were alcohol abusers. Mean education was 11.1 years (SD--standard deviation--3.7). A high prevalence of HIV-associated neurocognitive disorders (HAND, 47.1%) was present in HIV-infected patients: particularly, asymptomatic neurocognitive impairment (ANI) was found in 30.6%, mild neurocognitive disorder (MND) in 15% and HIV-associated dementia (HAD) in 1.5%. Male gender, low degree of education, AIDS diagnosis and gepatitis B virus (HBV) co-infection were factors independently associated with HAND in a multivariable logistic regression model. Our data suggest that patient-specific factors and AIDS diagnosis have a certain kind of impact in HAND occurrence. A complete neuropsychological screening must be recommended in all patients at HIV-infection diagnosis.

Clinical and immunological outcomes according to adherence to first-line HAART in a urban and rural cohort of HIV-infected patients in Burkina Faso, West Africa.

BACKGROUND: Aim of our study is to investigate the clinical and immunological outcomes according to first-line HAART adherence in a large cohort of HIV-infected patients in Burkina Faso. METHODS: A retrospective study was conducted between 2001 and 2009 among patients from two urban medical centers [St. Camille Medical Center (CMSC) and "Pietro Annigoni" Biomolecular Research Center (CERBA)] and 1 in the rural District of Nanoro (St. Camille District Hospital). Socio-demographical and clinical data were analyzed. Adherence was evaluated through a questionnaire investigating 5 key points related to drugs, consultations and blood exams, by assigning 0 to 2 points each up to 10 points overall. Data were collected at baseline and regularly thereafter. Adherence score was considered as a continuous variable and classified in optimal (8-10 points) and sub-optimal (0-7 points). Immunological outcome was evaluated as modification in CD4+ T-cell count over time, while predictors of death were explored by a univariate and multivariate Cox model considering adherence score as a time-varying covariate. RESULTS: A total of 625 patients were included: 455 (72.8%) were females, the median age was 33.3 (IQR 10.2) years, 204 (32.6.%) were illiterates, the median CD4+ T-cell count was 149 (IQR 114) cells/µl at baseline. At the end of the observation period we recorded 60/625 deaths and 40 lost to follow-up. The analysis of immunological outcomes showed a significant variation in CD4+ T-cell count between M12 and M24 only for patients with optimal adherence (Δ=78.2, p<0.001), with a significant Δ between the two adherence groups at M24 (8-10 vs 0-7, Δ=53.8, p=0.004). Survival multivariate analysis revealed that covariates significantly related to death included being followed at CERBA (urban area) or Nanoro (rural area), and receiving a regimen not including fixed dose combinations, (p=0.024, p=0.001 and p<0.001 respectively); conversely, an increasing adherence score as well as an optimal adherence score were significantly related to survival (p<0.001). CONCLUSIONS: Adherence to HAART remains pivotal to build up a good therapeutic outcome. Our results confirm that, according to our adherence system evaluation, less adherent patients have a higher risk of death and of inadequate CD4+ count recovery.

Physiopathology and clinical management of blackwater fever: a scoping review.

BACKGROUND: Blackwater fever (BWF) is a severe syndrome occurring in patients with malaria upon antimalarial treatment, characterized by massive intravascular haemolysis and haemoglobinuria. BWF is a neglected condition and management recommendations are unavailable. OBJECTIVES: We performed a scoping review to appraise available data on clinical picture, treatment and physiopathology of BWF, which could guide rationally its clinical management. METHODS: MEDLINE, EMBASE, LILACS, Web of Science, and Scopus databases, and the reference list of relevant publications, were searched. Papers reporting original data on BWF cases or investigating the physiopathology of BWF were eligible. Data regarding case characteristics, trigger event, clinical management and outcome were extracted. For papers investigating the physiopathology of BWF, study design and principal findings were extracted. No quality assessment was performed. Data are presented as numbers and percentages, and summary of findings, grouped by paper focus (clinical description or physiopathology). RESULTS: 101 papers were included. The majority of BWF cases were observed in autochthonous children (75.7%) and adults (15.3%), in contrast with historical perception that BWF patients were typically expatriates. Clinical management was described for 794 cases; corticosteroids were used in 23. Outcome was reported for 535 patients, with 18.1% mortality. The trigger was reported for 552 (47.5%) cases; in 70.4% identified as quinine. However, two RCT comparing artesunate and quinine for falciparum malaria treatment did not find significant difference in BWF occurrence after their administration. Two case-control studies did not find significant difference in G6PDH deficiency between malaria patients with and without BWF. CONCLUSIONS: The physiopathology and optimal treatment of BWF remain similarly unknown as they were over a century ago. Empirical supporting treatment approach seems reasonable, while change of antimalarial drug and use of corticosteroids remain object of debate.

Prevention of congenital Chagas disease by screening of mothers and monitoring of serological tests of neonates: the seven years' experience.

Approximately 14000 immigrants coming from the Cochabamba area of Bolivia, with an increased risk of congenital Chagas Disease (CD), are currently living in Bergamo, Italy. According to the World Health Organization (WHO) recommendation (2011), prevention of congenital CD involves testing all pregnant women at risk of infection and performing follow-up of their newborns. In our study, all pregnant women of Latin American origin were tested for the presence of Trypanosoma cruzi antibodies and children, born to mothers found to be positive, were followed up after delivery. T. cruzi antibodies were detected using a chemiluminescence immunoassay. The test was also performed on siblings and fathers of children with CD, and women of childbearing age to prevent the congenital infection, as proposed by 2011 WHO recommendation. In the study period 1105 patients were tested for CD, using a serological test: 934 (85%) were females and 171 (15%) were males. Of the 62 newborns, from mothers who tested positive, 28 were females and 34 were males. The number of positive adults and siblings identified was 148 (14%). Among the adults and siblings born between 1991 and 2011 only 3 (2%) of females tested positive to serological test. All neonates, with the exception of one, were classified as non-infected according to the follow-up of index value of CD serology. This study confirms the usefulness of serological tests and of their index value as follow-up. The difference of positivity rate for CD antibodies between people born before and after 1990 should be further investigated to generate information that potentially improve the prevention and control of CD.

Current pharmacotherapeutic strategies for Strongyloidiasis and the complications in its treatment.

INTRODUCTION: Strongyloidiasis, an infection caused by the soil-transmitted helminth Strongyloides stercoralis, can lead immunocompromised people to a life-threatening syndrome. We highlight here current and emerging pharmacotherapeutic strategies for strongyloidiasis and discuss treatment protocols according to patient cohort. We searched PubMed and Embase for papers published on this topic between 1990 and May 2022. AREAS COVERED: Ivermectin is the first-line drug, with an estimated efficacy of about 86% and excellent tolerability. Albendazole has a lower efficacy, with usage advised when ivermectin is not available or not recommended. Moxidectin might be a valid alternative to ivermectin, with the advantage of being a dose-independent formulation. EXPERT OPINION: The standard dose of ivermectin is 200 µg/kg single dose orally, but multiple doses might be needed in immunosuppressed patients. In the case of hyperinfection, repeated doses are recommended up to 2 weeks after clearance of larvae from biological fluids, with close monitoring and further dosing based on review. Subcutaneous ivermectin is used where there is impaired intestinal absorption/paralytic ileus. In pregnant or lactating women, studies have not identified increased risk with ivermectin use. However, with limited available data, a risk-benefit assessment should be considered for each case.

Impact of SARS-CoV-2 infection on tuberculosis outcome and follow-up in Italy during the first COVID-19 pandemic wave: a nationwide online survey.

Background: SARS-CoV-2 pandemic affected tuberculosis (TB) management. This Italian nationwide survey assessed COVID-19 impact on TB care and outcomes. Materials and methods: Twenty-one hospitals or referral centres fulfilled an online survey. Primary objective was to describe clinical features, outcomes and retention in care in subjects with latent TB infection (LTBI) or disease over the first wave of COVID-19 pandemic. Secondary objectives were the assessment of risk factors, co-morbidities, diagnostics, radiological findings, and outcomes of COVID-19 in the study population. Results: 254 patients with LTBI or active TB were included. In co-infected (SARS-CoV-2, LTBI/TB) patients, recovery occurred in 29/32 (90.6%) cases, death in one case. High retention in care was preserved. Conclusion: in our cohort, outcomes did not seem to be adversely conditioned by incident COVID-19.

Prevalence of Chagas disease and strongyloidiasis among HIV-infected Latin American immigrants in Italy - The CHILI study.

INTRODUCTION: Screening HIV-positive migrants for neglected tropical diseases having potential for life-threatening reactivation, such as Chagas disease and strongyloidiasis is not widely implemented. We evaluated the prevalence of these infections among a large cohort of HIV-infected migrants from Latin America living in Italy. METHOD: Cross-sectional study evaluating the prevalence of Trypanosoma cruzi and Strongyloides stercoralis infections in HIV-infected migrants from Latin America enrolled in the Italian Cohort of Antiretroviral-Naïve patients (ICONA) between 1997 and 2018, based on serology performed on sera stored in the ICONA Foundation biobank. Screening for Chagas disease was performed using two commercial ELISA complemented by commercial Immunoblot and CLIA if discordant. Strongyloidiasis was evaluated using a commercial ELISA. RESULTS: 389 patients were analysed. Fifteen (3.86%) had at least one positive Chagas ELISA test. Prevalence of Chagas disease was 0.5% or 1.29% depending on the confirmatory technique. Serology for strongyloidiasis was positive in 16 (4.11%) patients. Only Nadir CD4+ T cell count was associated with discordant serology for Chagas disease (p = 0.046). CONCLUSIONS: The accuracy of seroassays for Chagas disease and strongyloidiasis in HIV-positive patients is unclear. To avoid missing potentially life-threatening infections, we suggest implementing additional diagnostic strategies in at-risk patients with inconclusive serology results.

A large case series of travel-related Mansonella perstans (vector-borne filarial nematode): a TropNet study in Europe.

BACKGROUND: Infection with Mansonella perstans is a neglected filariasis, widely distributed in sub-Saharan Africa, characterized by an elusive clinical picture; treatment for mansonellosis is not standardized. This retrospective study aimed to describe the clinical features, treatment schemes and evolution, of a large cohort of imported cases of M. perstans infection seen in four European centres for tropical diseases. METHODS: Mansonella perstans infections, diagnosed by identification of blood microfilariae in migrants, expatriates and travellers, collected between 1994 and 2018, were retrospectively analysed. Data concerning demographics, clinical history and laboratory examinations at diagnosis and at follow-up time points were retrieved. RESULTS: A total of 392 patients were included in the study. Of the 281 patients for whom information on symptoms could be retrieved, 150 (53.4%) reported symptoms, abdominal pain and itching being the most frequent. Positive serology and eosinophilia were present in 84.4% and 66.1%, respectively, of those patients for whom these data were available. Concomitant parasitic infections were reported in 23.5% of patients. Treatment, administered to 325 patients (82.9%), was extremely heterogeneous between and within centres; the most commonly used regimen was mebendazole 100 mg twice a day for 1 month. A total of 256 (65.3%) patients attended a first follow-up, median 3 months (interquartile range 2-12) after the first visit; 83.1% of patients having received treatment based on mebendazole and/or doxycycline, targeting Wolbachia, became amicrofilaremic, 41.1-78.4% of whom within 12 months from single treatment. CONCLUSIONS: Lack of specific symptoms, together with the inconstant positivity of parasitological and antibody-based assays in the infected population, makes the clinical suspicion and screening for mansonellosis particularly difficult. Prospective studies evaluating prevalence of infection in migrants from endemic areas, infection-specific morbidity, presence of Wolbachia endosymbionts in M. perstans populations from different geographical areas and efficacy of treatment regimens are absolutely needed to optimize the clinical management of infection.

Development and validation of SCOPE score: A clinical score to predict COVID-19 pneumonia progression to severe respiratory failure.

Most patients infected with SARS-CoV-2 (COVID-19) experience mild, non-specific symptoms, but many develop severe symptoms associated with an excessive inflammatory response. Elevated plasma concentrations of soluble urokinase plasminogen activator receptor (suPAR) provide early warning of progression to severe respiratory failure (SRF) or death, but access to suPAR testing may be limited. The Severe COvid Prediction Estimate (SCOPE) score, derived from circulating concentrations of C-reactive protein, D- dimers, interleukin-6, and ferritin among patients not receiving non-invasive or invasive mechanical ventilation during the SAVE-MORE study, offers predictive accuracy for progression to SRF or death within 14 days comparable to that of a suPAR concentration of ≥6 ng/mL (area under receiver operator characteristic curve 0.81 for both). The SCOPE score is validated in two similar independent cohorts. A SCOPE score of 6 or more is an alternative to suPAR for predicting progression to SRF or death within 14 days of hospital admission for pneumonia, and it can be used to guide treatment decisions.

Preventive chemotherapy for the control of strongyloidiasis in school-age children: Estimating the ivermectin need.

BACKGROUND: Strongyloides stercoralis is a soil-transmitted helminth (STH) that affects approximately 600 million people worldwide. Interventions targeting S. stercoralis have not been implemented yet. Specific treatment (ivermectin) could be included in already ongoing preventive chemotherapy (PC) campaigns targeting other STHs. The aim of this study was to estimate the quantity of ivermectin needed for an integrated STH/S. stercoralis control program. METHODODOLOGY/PRINCIPAL FINDINGS: Our study estimates the number of school- age children (SAC) (the main focus of STH deworming campaigns) in need of PC with ivermectin. The normal approximation of the binomial distribution was adopted to calculate the hypothetical prevalence distribution in each endemic country. Considering prevalence thresholds for PC equal to 10%, 15%, and 20%, we estimated the number of SAC in need of treatment. We adjusted the estimates accounting for ivermectin distributed in lymphatic filariasis and onchocerciasis elimination programs and excluded from our calculation areas where Loa loa is endemic. The global number of SAC that should be targeted in PC campaigns was estimated at 283.9 M (95% CI: 163.4-368.8), 207.2 M (95% CI: 160.9-380.7), and 160.7 M (95% CI: 86.6-225.7) when the threshold for intervention was set to 10%, 15%, and 20%, respectively. India, China, Indonesia, Bangladesh, and Nigeria accounted for about 50% of the global SAC would have to be covered by PC intervention. CONCLUSIONS/SIGNIFICANCE: Our analysis may support endemic countries to evaluate the ivermectin quantity needed for integrating strongyloidiasis in the existing STH programs. These estimates might also show to generic drug manufacturers the size of the potential market for ivermectin and encourage its production.

Large multicystic spinal lesion in a young African migrant: a problem of differential diagnosis.

We describe a rare case of large, fully cystic spinal schwannoma in a young adult from The Gambia. The initial clinical suspicion was spinal cystic echinococcosis. He came to our attention reporting progressive walking impairment and neurological symptoms in the lower limbs. An expansive lesion extending from L2 to S1 was shown by imaging (ie, CT scan and MRI). Differential diagnoses included aneurysmal bone cyst and spinal tuberculosis and abscess; the initial suggested diagnosis of spinal cystic echinococcosis was discarded based on contrast enhancement results. The final diagnosis of cystic schwannoma was obtained by histopathology of the excised mass. Cystic spinal lesions are rare and their differential diagnosis is challenging. Awareness of autochthonous and tropical infectious diseases is important, especially in countries experiencing consistent migration flow; however, it must be kept in mind that migrants may also present with 'non-tropical' pathologies.

Emergence of Lyme borreliosis in the province of Verona, Northern Italy: Five-years of sentinel surveillance.

We investigated the epidemiology, clinical manifestations, laboratory data and antibiotic treatment of Lyme borreliosis in the province of Verona, Northern Italy, during the period 2015-2019. One hundred and 29 cases of Lyme borreliosis were diagnosed in a single hospital representing 27 % of all cases reported in the Veneto region in the same period. The mean annual incidence of Lyme borreliosis was 0.992/100,000 inhabitants. A peak incidence of 2/100,000 inhabitants was observed in 2018. Early localized Lyme borreliosis was the most common presentation (74 %), followed by early disseminated Lyme borreliosis (21 %). One possible early Lyme neuroborreliosis and two cranial neuropathies were diagnosed. IgM and/or IgG borrelia antibodies were positive in 90 % of the cases. This significant increase of Lyme borreliosis incidence in the province of Verona highlights the need to increase knowledge on its epidemiology and clinical manifestation among both the general population and clinicians to allow early diagnosis and treatment.

Antibody Response to the BNT162b2 mRNA COVID-19 Vaccine in Subjects with Prior SARS-CoV-2 Infection.

Although antibody levels progressively decrease following SARS-CoV-2 infection, the immune memory persists for months. Thus, individuals who naturally contracted SARS-CoV-2 are expected to develop a more rapid and sustained response to COVID-19 vaccines than naïve individuals. In this study, we analyzed the dynamics of the antibody response to the BNT162b2 mRNA COVID-19 vaccine in six healthcare workers who contracted SARS-CoV-2 in March 2020, in comparison to nine control subjects without a previous infection. The vaccine was well tolerated by both groups, with no significant difference in the frequency of vaccine-associated side effects, with the exception of local pain, which was more common in previously infected subjects. Overall, the titers of neutralizing antibodies were markedly higher in response to the vaccine than after natural infection. In all subjects with pre-existing immunity, a rapid increase in anti-spike receptor-binding domain (RBD) IgG antibodies and neutralizing antibody titers was observed one week after the first dose, which seemed to act as a booster. Notably, in previously infected individuals, neutralizing antibody titers 7 days after the first vaccine dose were not significantly different from those observed in naïve subjects 7 days after the second vaccine dose. These results suggest that, in previously infected people, a single dose of the vaccine might be sufficient to induce an effective response.

Tuberculosis and pharmacological interactions: A narrative review.

Even if major improvements in therapeutic regimens and treatment outcomes have been progressively achieved, tuberculosis (TB) remains the leading cause of death from a single infectious microorganism. To improve TB treatment success as well as patients' quality of life, drug-drug-interactions (DDIs) need to be wisely managed. Comprehensive knowledge of anti-TB drugs, pharmacokinetics and pharmacodynamic (PK/PD) parameters, potential patients' changes in absorption and distribution, possible side effects and interactions, is mandatory to built effective anti-TB regimens. Optimization of treatments and adherence to international guidelines can help bend the curve of TB-related mortality and, ultimately, decrease the likelihood of treatment failure and drop-out during anti-TB treatment. Aim of this paper is to describe the most relevant DDIs between anti-TB and other drugs used in daily clinical practice, providing an updated and "easy-to-use" guide to minimize adverse effects, drop-outs and, in the long run, increase treatment success.

Regulatory T Cells as Predictors of Clinical Course in Hospitalised COVID-19 Patients.

Background: The host immune response has a prominent role in the progression and outcome of SARS-CoV-2 infection. Lymphopenia has been described as an important feature of SARS-CoV-2 infection and has been associated with severe disease manifestation. Lymphocyte dysregulation and hyper-inflammation have been shown to be associated with a more severe clinical course; however, a T cell subpopulation whose dysfunction correlate with disease progression has yet to be identify. Methods: We performed an immuno-phenotypic analysis of T cell sub-populations in peripheral blood from patients affected by different severity of COVID-19 (n=60) and undergoing a different clinical evolution. Clinical severity was established based on a modified WHO score considering both ventilation support and respiratory capacity (PaO2/FiO2 ratio). The ability of circulating cells at baseline to predict the probability of clinical aggravation was explored through multivariate regression analyses. Results: The immuno-phenotypic analysis performed by multi-colour flow cytometry confirmed that patients suffering from severe COVID-19 harboured significantly reduced circulating T cell subsets, especially for CD4+ T, Th1, and regulatory T cells. Peripheral T cells also correlated with parameters associated with disease severity, i.e., PaO2/FiO2 ratio and inflammation markers. CD4+ T cell subsets showed an important significant association with clinical evolution, with patients presenting markedly decreased regulatory T cells at baseline having a significantly higher risk of aggravation. Importantly, the combination of gender and regulatory T cells allowed distinguishing between improved and worsened patients with an area under the ROC curve (AUC) of 82%. Conclusions: The present study demonstrates the association between CD4+ T cell dysregulation and COVID-19 severity and progression. Our results support the importance of analysing baseline regulatory T cell levels, since they were revealed able to predict the clinical worsening during hospitalization. Regulatory T cells assessment soon after hospital admission could thus allow a better clinical stratification and patient management.

Antibody response induced by the BNT162b2 mRNA COVID-19 vaccine in a cohort of health-care workers, with or without prior SARS-CoV-2 infection: a prospective study.

OBJECTIVES: To assess the antibody response to BNT162b2 mRNA COVID-19 vaccine in a cohort of health-care workers (HCW), comparing individuals with previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and SARS-CoV-2-naive individuals. METHODS: HCW were tested at T0 (day of first dose), T1 (day of second dose) and T2 (2-3 weeks after second dose) for IgG anti-nucleocapsid protein, IgM anti-spike protein and IgG anti-receptor binding domain (IgG-RBD-S). The antibody response was compared between four main groups: group A, individuals with previous infection and positive antibodies at baseline; group B, individuals with the same history but negative antibodies; group C, individuals with no infection history but positive antibodies; group D, naive individuals. Repeated measures analysis was used to compare results over time-points. RESULTS: A total of 1935 HCW were included. Median IgG-RBD-S titre was significantly higher for group A (232 individuals) than for group B (56 individuals) both at T1 (A: 22 763 AU/mL, interquartile range (IQR) 14 222-37 204 AU/mL; B: 1373 AU/mL, IQR 783-3078 AU/mL, p 0.0003) and T2 (A: 30 765 AU/mL, IQR 19 841-42 813 AU/mL; B: 13 171 AU/mL, IQR 2324-22 688 AU/mL, p 0.0038) and for group D (1563 individuals; 796 AU/mL, IQR 379-1510 AU/mL at T1; 15 494 AU/mL, IQR 9122-23 916 AU/mL at T2, p < 0.0001 for both time-points). T1 values of group A were also significantly higher than T2 values of group D (p < 0.0001). Presence of symptoms, younger age and being female were associated with stronger antibody response. HCW infected in March showed a significantly stronger response (T1: 35 324 AU/mL, IQR 22 003-44 531 AU/mL; T2: 37 648 AU/mL, IQR 27 088-50 451 AU/mL) than those infected in November (T1: 18 499 AU/mL, IQR 11 492-27 283 AU/mL; T2: 23 210 AU/mL, IQR 18 074-36 086 AU/mL, p < 0.0001 for both time-points. CONCLUSIONS: Individuals with past SARS-CoV-2 infection had a strong antibody response after one single vaccine shot. A single dose might be sufficient for this group, regardless of the time elapsed since infection; however, the clinical correlation with antibody response needs to be studied.