Objectives The aim of this study was to trace contacts of COVID-19 hospitalised patients and determine the risk factors of infection in urban areas. Study design Longitudinal analysis of contacts identified from index cases. Methods A contact tracing study was carried out in the Northern Metropolitan area of Barcelona, Spain, during the inter-epidemic lapse of May to July 2020, a period of low SARS-CoV-2 incidence. Index cases were notified from the referral hospital. Contacts were traced and followed-up for 14 days. Reverse transcription polymerase chain reaction (RT-PCR) was performed at day 0 and day 14 for contacts. Results In total, 368 contacts were identified from 81 index cases (median of 7 contacts per index case), from which 308 were traced successfully. The median age of contacts was of 28 years old, 62% (223 of 368) were males and 28 were non-nationals (34.1%). During the follow-up period, 100 contacts tested positive for COVID-19 (32.5% [95% confidence interval {CI} = 27.3–38.0]), with a secondary infection rate of 48.3% (95% CI = 40.8–55.9) among housemates. Clusters of index and respective contacts tended to aggregate within disadvantaged neighbourhoods (p < 0.001), and non-national index cases resulted in higher secondary infection rates compared with nationals (51.0% [95% CI = 41.0–60.9] vs 22.3% [95% CI = 16.8–28.8]; p < 0.001). Conclusions Disadvantaged communities experience a disproportionate burden of COVID-19 and may act as infection reservoirs. Contact tracing with a cross-cutting approach among these communities is required, especially during inter-epidemic periods.

T he mass vaccination against SARS-CoV-2 that began at the end of 2020 reduced COVID-19-related mortality and severity in countries where substantial vaccine coverage was achieved (1,2). The vaccines also had a protective effect against the most recent variants (3,4). However, expectations that vaccines would stop community transmission of SARS-CoV-2 through herd immunity were quickly dampened by the early observation of infection and re-infection among vaccinated persons; waning vaccine effectiveness against transmission (VET) over time was observed (1,3) and confirmed in a large systematic literature review (5). Despite these results, protective effects of vaccination against infection among contacts have been reported (6). The vaccination status of index case-patients was also shown to play a role (6), underscoring the importance of vaccination for reducing the circulation of SARS-CoV-2. Nonetheless, the emergence of new variants of concern (VOC) with increased infectivity is an ongoing challenge for VET of currently licensed vaccines; early reports have shown a substantially lower VET for the Delta variant (B.1.617.2) compared with previous VOCs (7). Furthermore, rapid replacement of the Delta variant by Omicron (B.1.1.529) began in late 2021; the Omicron variant showed a transmission advantage because of its shorter generation time (S. Abbott et al., unpub. data, https://www.medrxiv.org/content/10.1101/2 022.01.08.22268920v1).Evaluating both variant virulence and SARS-CoV-2 VET under high vaccine coverage levels has major epidemiologic, social, and policy implications. We report the results of an observational study of household contacts of SARS-CoV-2-infected index case-patients during a Delta variant-dominant period from September to December 2021 and an Omicron variant-dominant period during January 2022 in a north-metropolitan area of Barcelona, Spain. We

No abstract

BackgroundSchistosomiasis among migrant populations in Europe is an underdiagnosed infection, yet delayed treatment may have serious long-term consequences. In this study we aimed to characterize the clinical manifestations of Schistosoma infection among migrant women, and the degree of underdiagnosis.MethodsWe carried out a prospective cross-sectional study among a migrant population living in the North Metropolitan Barcelona area and coming from schistosomiasis-endemic countries. We obtained clinical, laboratory and socio-demographic data from electronic clinical records, as well as information about years of residence and previous attendance at health services. Blood sample was obtained and schistosomiasis exposure was assessed using a specific ELISA serological test.ResultsFour hundred and five patients from schistosomiasis-endemic regions were screened, of whom 51 (12.6%) were female. Seropositivity prevalence was 54.8%, but considering women alone we found a prevalence of 58.8% (30 out of 51). The median age of the 51 women was 41.0 years [IQR (35–48)] and the median period of residence in the European Union was 13 years [IQR (10–16)]. Schistosoma-positive women (N = 30) showed a higher prevalence of gynecological signs and symptoms compared to the seronegative women (96.4 vs. 66.6%, p = 0.005). Among seropositive women, the median number of visits to Sexual and Reproductive Health unit prior to diagnosis of schistosomiasis was 41 [IQR (18–65)].ConclusionThe high prevalence of signs and symptoms among seropositive women and number of previous visits suggest a high rate of underdiagnosis and/or delayed diagnosis of Schistosoma infection, particularly female genital schistosomiasis, among migrant females.