Highlights Hydroxychloroquine (HCQ) 2400 mg over 5 days was used in Belgium for COVID-19. Impact of HCQ on mortality among 8075 patients with COVID-19 was assessed. Lower mortality in HCQ-treated patients as compared to supportive care. Lower mortality was irrespective of symptom duration.

BackgroundCancer seems to have an independent adverse prognostic effect on COVID-19-related mortality, but uncertainty exists regarding its effect across different patient subgroups. We report a population-based analysis of patients hospitalised with COVID-19 with prior or current solid cancer versus those without cancer.MethodsWe analysed data of adult patients registered until 24 May 2020 in the Belgian nationwide database of Sciensano. The primary objective was in-hospital mortality within 30 days of COVID-19 diagnosis among patients with solid cancer versus patients without cancer. Severe event occurrence, a composite of intensive care unit admission, invasive ventilation and/or death, was a secondary objective. These endpoints were analysed across different patient subgroups. Multivariable logistic regression models were used to analyse the association between cancer and clinical characteristics (baseline analysis) and the effect of cancer on in-hospital mortality and on severe event occurrence, adjusting for clinical characteristics (in-hospital analysis).ResultsA total of 13 594 patients (of whom 1187 with solid cancer (8.7%)) were evaluable for the baseline analysis and 10 486 (892 with solid cancer (8.5%)) for the in-hospital analysis. Patients with cancer were older and presented with less symptoms/signs and lung imaging alterations. The 30-day in-hospital mortality was higher in patients with solid cancer compared with patients without cancer (31.7% vs 20.0%, respectively; adjusted OR (aOR) 1.34; 95% CI 1.13 to 1.58). The aOR was 3.84 (95% CI 1.94 to 7.59) among younger patients (<60 years) and 2.27 (95% CI 1.41 to 3.64) among patients without other comorbidities. Severe event occurrence was similar in both groups (36.7% vs 28.8%; aOR 1.10; 95% CI 0.95 to 1.29).ConclusionsThis population-based analysis demonstrates that solid cancer is an independent adverse prognostic factor for in-hospital mortality among patients with COVID-19. This adverse effect was more pronounced among younger patients and those without other comorbidities. Patients with solid cancer should be prioritised in vaccination campaigns and in tailored containment measurements.

e67 asymptomatic carriers of the virus could represent an important driver of transmission. To limit the spread of SARS-CoV-2 in closed residential facilities, we iterate the importance of widely applying extensive infection prevention and control measures as long as the epidemic is ongoing.We declare no competing interests.

In Belgium, high-risk contacts of an infected person were offered PCR-testing irrespective of their vaccination status. We estimated vaccine effectiveness (VE) against infection and onwards transmission, controlling for previous infections, household-exposure and temporal trends. We included 301,741 tests from 25 January to 24 June 2021. Full-schedule vaccination was associated with significant protection against infection. In addition, mRNA-vaccines reduced onward transmission: VE-estimates increased to >90% when index and contact were fully vaccinated. The small number of viral-vector vaccines included limited interpretability.

Background In response to the COVID-19 epidemic, caused by a novel coronavirus, it was of great importance to rapidly collect as much accurate information as possible in order to characterize the public health threat and support the health authorities in its management. Hospital-based surveillance is paramount to monitor the severity of a disease in the population. Methods Two separate surveillance systems, a Surge Capacity survey and a Clinical survey, were set up to collect complementary data on COVID-19 from Belgium’s hospitals. The Surge Capacity survey collects aggregated data to monitor the hospital capacity through occupancy rates of beds and medical devices, and to follow a set of key epidemiological indicators over time. Participation is mandatory and the daily data collection includes prevalence and incidence figures on the number of COVID-19 patients in the hospital. The Clinical survey is strongly recommended by health authorities, focusses on specific patient characteristics and relies on individual patient data provided by the hospitals at admission and discharge. Conclusions This national double-level hospital surveillance was implemented very rapidly after the first COVID-19 patients were hospitalized and revealed to be crucial to monitor hospital capacity over time and to better understand the disease in terms of risk groups and outcomes. The two approaches are complementary and serve different needs.

The treatment of latent tuberculosis infection (LTBI) in target populations is one of the current WHO strategies for preventing active tuberculosis (TB) infection and reducing theT he screening and treatment for LTBI in target populations in order to prevent TB and reduce the Mycobacterium tuberculosis reservoir are some of the main strategies of the WHO's Global Plan to Stop TB (http://www.who.int/tb/publications/global _report/en). However, a major obstacle to the instauration and effectiveness of these preventive measures resides in the lack of a gold standard LTBI screening tool.For several decades, the tuberculin skin test (TST) has been the main screening test for LTBI despite its lack of both sensitivity and specificity (1). Subsequently, T-cell-based gamma interferon release assays (IGRAs) in response to antigens encoded in the M. tuberculosis genomic region of difference 1 (RD-1) and RD-11 were developed and commercialized (QuantiFERON-TB Gold In-Tube [QFT-GIT] and T-SPOT.TB tests), with the objective of offering a more powerful diagnostic tool for LTBI. These tests offer a higher specificity than TST particularly in countries with high Mycobacterium bovis BCG vaccination coverage (2). However, recent studies suggest that these short-incubation RD-1-based IGRAs may have suboptimal sensitivities (3, 4).An alternative IGRA in response to the native mycobacterial antigen heparin-binding hemagglutinin (nHBHA-IGRA) that uses a longer incubation time than the commercialized IGRA has been validated in immunocompetent adults in the screening for LTBI (5). This assay not only demonstrates a high sensitivity and specificity for LTBI diagnosis but also a capacity to detect remote M. tuberculosis infections, a substantial advantage over the commercialized IGRAs (5-7).Remote M. tuberculosis infections are generally believed to be identified through central memory T-cell (Tcm) responses detected with long-incubation IGRAs (3, 4). Here, however, we demonstrate that both recent and remote M. tuberculosis infections can be identified through effector memory T-cell (Tem) responses using a short-incubation nHBHA-IGRA, the upgraded assay presented in this study. Our results suggest that the detection of IFN-␥-producing CD4 ϩ Tem in response to nHBHA reflects the persistence of M. tuberculosis antigens and therefore a true state of latency.(These results were presented in part at the European Congress of Immunology, Glasgow, Scotland, 5 to 8 September 2012, and at the MycoClub,

The objective of this study was to investigate the incidence and risk factors associated with COVID-19 vaccine breakthrough infections. We included all persons ≥18 years that had been fully vaccinated against COVID-19 for ≥14 days, between 1 February 2021 and 5 December 2021, in Belgium. The incidence of breakthrough infections (laboratory confirmed SARS-CoV-2-infections) was determined. Factors associated with breakthrough infections were analyzed using COX proportional hazard models. Among 8,062,600 fully vaccinated adults, we identified 373,070 breakthrough infections with an incidence of 11.2 (95%CI 11.2–11.3)/100 person years. Vaccination with Ad26.COV2.S (HR1.54, 95%CI 1.52–1.56) or ChAdOx1 (HR1.68, 95%CI 1.66–1.69) was associated with a higher risk of a breakthrough infection compared to BNT162b2, while mRNA-1273 was associated with a lower risk (HR0.68, 95%CI 0.67–0.69). A prior COVID-19-infection was protective against a breakthrough infection (HR0.23, 95%CI 0.23–0.24), as was an mRNA booster (HR0.44, 95%CI 0.43–0.45). During a breakthrough infection, those who had a prior COVID-19 infection were less likely to have COVID-19 symptoms of almost all types than naïve persons. We identified risk factors associated with breakthrough infections, such as vaccination with adenoviral-vector vaccines, which could help inform future decisions on booster vaccination strategies. A prior COVID-19 infection lowered the risk of breakthrough infections and of having symptoms, highlighting the protective effect of hybrid immunity.

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