We are in the midst of a pandemic caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes the coronavirus disease 2019 (COVID-19). SARS-CoV-2 has caused more than two million deaths after one year of the pandemic. The world is experiencing a deep economic recession. Safe and effective vaccines are needed to prevent further morbidity and mortality. Vaccine candidates against COVID-19 have been developed at an unprecedented speed, with more than 200 vaccine candidates currently under investigation. Among those, 20 candidates have entered the clinical Phase 3 to evaluate efficacy, and three have been approved by the European Medicines Agency. The aim of immunization is to act against infection, disease and/or transmission. However, the measurement of vaccine efficacy is challenging, as efficacy trials need to include large cohorts with verum and placebo cohorts. In the future, this will be even more challenging as further vaccine candidates will receive approval, an increasing number of humans will receive vaccinations and incidence might decrease. To evaluate novel and second-generation vaccine candidates, randomized placebo-controlled trials might not be appropriate anymore. Correlates of protection (CoP) could be an important tool to evaluate novel vaccine candidates, but vaccine-induced CoP have not been clearly defined for SARS-CoV-2 vaccines. In this review, we report on immunogenicity against natural SARS-CoV-2 infection, vaccine-induced immune responses and discuss immunological markers that can be linked to protection. By discussing the immunogenicity and efficacy of forerunner vaccines, we aim to give a comprehensive overview of possible efficacy measures and CoP.

ObjectiveTo assess the variation of effect estimates in the analysis of mortality and length of stay (LOS) in patients with infections caused by extended-spectrum beta-lactamase (ESBL)-producingEnterobacteriaceae.DesignSystematic review and meta-analysisMethodsLiterature search for clinical studies from 1 January 1960 to 1 October 2018 was conducted in PubMed. Primary outcomes were risk ratios (RRs) of all-cause and attributable mortality and weighted mean differences (WMDs) in LOS in patients with bloodstream infections (BSIs) and non-invasive infections. Any change in the effect estimates was assessed by grouping studies according to design, setting, economy-based country classification, reporting period, microbiological aetiology, infection type and adjustment for appropriateness of empirical treatment. The impact of ESBL production was calculated using random-effect meta-analysis and heterogeneity was evaluated by I2statistics and metaregression.ResultsEighty-four studies including 22 030 patients and 149 outcome measures were included in the meta-analysis. Most studies were retrospective cohorts from high-income countries, providing unadjusted estimates. ESBL production in patients with BSIs (56 studies) increased the RR for all-cause mortality by a factor of 1.70 (95% CI 1.52 to 1.90; p<0.001), attributable mortality (16 studies) by 1.75 (95% CI 1.448 to 2.108; p<0.001) and WMD in the intensive care unit by 3.07 days (95% CI 1.61 to 4.54; p<0.001). WMD in hospital LOS was significantly higher in BSIs (4.41 days; 95% CI 3.37 to 5.46; p<0.001) and non-invasive (2.19 days; 95% CI 1.56 to 2.81; p<0.001). Subgroup analyses showed variation of estimates by study design, population, strain and assessment of appropriateness of empiric treatment. High heterogeneity was observed in all analyses.ConclusionsCurrent evidence of the clinical burden of infections caused by ESBL-producing bacteria is highly heterogeneous and based mainly on unadjusted estimates derived from retrospective studies. Despite these limitations, ESBL production in strains causing BSIs seems associated with higher all-cause and attributable mortality and longer hospitalisation.

Early detection of severe forms of COVID-19 is absolutely essential for timely triage of patients. We longitudinally followed-up two well-characterized patient groups, hospitalized moderate to severe (n = 26), and ambulatory mild COVID-19 patients (n = 16) at home quarantine. Human D-dimer, C-reactive protein (CRP), ferritin, cardiac troponin I, interleukin-6 (IL-6) levels were measured on day 1, day 7, day 14 and day 28. All hospitalized patients were SARS-CoV-2 positive on admission, while all ambulatory patients were SARS-CoV-2 positive at recruitment. Hospitalized patients had higher D-dimer, CRP and ferritin, cardiac troponin I and IL-6 levels than ambulatory patients (p < 0.001, p < 0.001, p = 0.016, p = 0.035, p = 0.002 respectively). Hospitalized patients experienced significant decreases in CRP, ferritin and IL-6 levels from admission to recovery (p < 0.001, p = 0.025, and p = 0.001 respectively). Cardiac troponin I levels were high during the acute phase in both hospitalized and ambulatory patients, indicating a potential myocardial injury. In summary, D-dimer, CRP, ferritin, cardiac troponin I, IL-6 are predictive laboratory markers and can largely determine the clinical course of COVID-19, in particular the prognosis of critically ill COVID-19 patients.

Surveillance data are considered essential to appropriate empiric antibiotic therapy and stewardship. The objective of this study was to determine if a change in the rates of antibiotic resistance impacts antibiotic use in European hospitals. Glycopeptides use was selected to study the correlation between resistance rates and antibiotic use because of the restricted spectrum against resistant gram positive bacteria. PubMed, ECDC databases and national/regional surveillance systems were searched to identify glycopeptides´ consumption in defined daily dose per 1000 inhabitant-days (DID) and rate of methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant coagulase negative staphylococci (MRCoNS), and vancomycin-resistant enterococci (VRE) in bloodstream infections (BSIs) in European countries between 1997 and 2015. Time trends were studied and associations between DID and BSI resistance rates were tested using multi-level mixed effect models. To account for the gap in the publication and dissemination of the yearly resistance data, a 2-year lag in the resistance rates was applied. Data on glycopeptides´ DID and resistance rates of target microorganisms in blood cultures were identified among 31 countries over a 19-year period. Glycopeptides use significantly increased (p<0·0001) while rates of MRSA BSIs decreased in majority of the countries (p<0·0001) and MRCoNS and VRE BSIs remained stable. Variation in glycopeptides’ DID was not associated with variation in BSIs due to MRSA (p = 0·136) and VRE (p = 0·613). After adjusting for MRCoNS and VRE resistance rates, among 21 countries, 11 (52%) had a concordant and 10 (48%) a discordant trend in yearly glycopeptides´ DID and MRSA BSI rates. No correlation was found between resistance rates and DID data even among 8 countries with more than 5% decrease in MRSA rates over time. (RC -0·009, p = 0·059). Resistance rate of MRSA, MRCoNS, and VRE BSIs does not impact DID of glycopeptides in European hospitals. This finding is key to redefining the role and structure of antimicrobial surveillance and stewardship programmes.

The emergence and international spread of SARS-CoV-2 led to unprecedented challenges for international travelers including health-related concerns and international travel restrictions. Remarkably, overseas travelers consulted at our travel clinic during the first quarter of 2020 were apparently not disconcerted by the evolving pandemic with a continuously high rate of consultations at our center; 85% of travelers did not actively inquire about COVID-19 during the pretravel consultation including individuals with clinically significant immunosuppression constituting a high-risk group for COVID-19-related adverse health outcome. This experience demonstrates the societal responsibility of travel medicine practitioners to proactively provide unbiased information about the health-related and travel-related impact of newly emerging infections.

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The development of an effective vaccine against SARS-CoV-2 marks one of the highest priorities during the ongoing pandemic. However, recruitment of participants for clinical trials can be challenging, and recruitment failure is among the most common reasons for discontinuation in clinical trials. From 20 May 2020, public announcements about a planned phase I trial of the vaccine candidate MVA-SARS-2-S against SARS-CoV-2 began, and interested individuals started contacting the study team via designated e-mail. All emails received from these individuals between 20 May 2020–30 September 2020 were assessed. Of the 2541 interested volunteers, 62% contacted the study team within three days after the first media announcement. The average age was 61 years (range 16–100), 48% of volunteers were female and 52% male. A total of 274, 186, and 53 individuals, respectively, reported medical pre-conditions, were health-care workers, or had frequent inter-person contacts. In conclusion, we report a high number of volunteers, with a considerable percentage stating factors for an elevated risk to acquire COVID-19 or develop severe disease. Factors such as media coverage and the perception of a disease as an acute threat may influence the individual’s choice to volunteer for a vaccine trial. Our data provide first important insights to better understand reasons to participate in such trials to facilitate trial implementation and recruitment.

Introduction Use of hydroxychloroquine in patients with coronavirus disease 2019 (COVID-19) was widespread and uncontrolled until recently. Patients vulnerable to severe COVID-19 are at risk of hydroxychloroquine interactions with co-morbidities and co-medications contributing to detrimental, including fatal, adverse treatment effects. Methods A retrospective survey was undertaken of health conditions and co-medications of patients with COVID-19 who were pre-screened for enrolment in a randomized, double-blind, placebo-controlled hydroxychloroquine multi-centre trial. Results The survey involved 305 patients [median age 71 (interquartile range 59–81) years]. The majority of patients ( n = 279, 92%) considered for inclusion in the clinical trial were not eligible, mainly due to safety concerns caused by health conditions or co-medications. The most common were QT-prolonging drugs ( n = 188, 62%) and haematologic/haemato-oncologic diseases ( n = 39, 13%) which prohibited the administration of hydroxychloroquine. In addition, 165 (54%) patients had health conditions and 167 (55%) patients were on co-medications that did not prohibit the use of hydroxychloroquine but had a risk of adverse interactions with hydroxychloroquine. The most common were diabetes ( n = 86, 28%), renal insufficiency ( n = 69, 23%) and heart failure ( n = 58, 19%). Conclusion The majority of hospitalized patients with COVID-19 had health conditions or took co-medications precluding safe treatment with hydroxychloroquine. Therefore, hydroxychloroquine should be administered with extreme caution in elderly patients with COVID-19, and only in clinical trials.