ABSTRACT
BACKGROUND: Efficient digitization in medicine still is in its infancy but undeniably has great potential for current and future challenges in health care. Thus far, the rollout of medical apps has not resulted in widespread use of smartphones in the German health care sector-the reasons for this have not been clarified so far. Nevertheless, the lack of user involvement in the development process and content creation might contribute to low acceptance of these products. OBJECTIVE: This study aims to outline an approach to involve medical expertise without any coding knowledge for developing medical app content and functions. METHODS: An end user-operable backend was built. Its usability was evaluated using a usability evaluation test protocol. The results of the usability tests were evaluated by the app development team, and the usability test was repeated for optimizing backend usability. In total, 40 criteria to measure the ease of app usage were defined a priori. The usability test comprised 20 tasks that had to be fulfilled. Usability tasks were analyzed for completion, dropout, and test duration. Due to the COVID-19 pandemic, digital videoconferencing platforms (Zoom and QuickTime Player) were used to complete usability questionnaires. Finally, several backend-based apps for several specialties (infectiology, plastic and reconstructive surgery, and orthopedics) were developed by health care professionals as prototypes. RESULTS: Initial usability testing was conducted with 5 participants (4 men and 1 woman; mean age 39.2, SD 5.97 years). All of them could complete the assigned backend tasks with only a few workflow interruptions and some minor errors. After usability optimization, the workflow completion time decreased from 5.03 minutes to 3.50 minutes, indicating a time saving. The basic backend structure was clear to all test users and the handling was intuitive to learn. Some minor errors in the backend occurred during the test rounds. The apps developed using the aforementioned approach are in clinical use as a proof of concept. CONCLUSIONS: Backends offering operability for medical professionals might have great potential for app development in the mobile health sector. Sophisticated and time-saving usability are pivotal for the acceptance of medical software, as illustrated by the backend-based apps presented herein, which are in clinical use as a proof of concept. Basic interventions are essential and sufficient for adequate usability optimization. Practicable, well-structured software usability evaluation is possible based on the usability evaluation test protocol.
ABSTRACT
Knowledge regarding the sustainability of immune responses after COVID-19 vaccination is important, e.g., to decide whom and when to booster. Thus, we analyzed antibody titers in firefighters six months after vaccination with the mRNA-based vaccine Comirnaty. SARS-CoV-2 spike-binding antibodies (bAb) were quantified and compared to peak responses determined in healthcare workers (HCW). For the firefighters, neutralizing antibodies (nAb) were also analyzed. Six months after the second vaccine dose, all analyzed firefighters had detectable bAb, and 91% exhibited nAb titers above 1:16. However, actual titers six months after vaccination were over 12-fold lower than in the HCW control group four weeks after vaccination. bAb and nAb responses showed a significant correlation, and age correlated inversely with antibody responses. Unexpectedly, participants with a body mass index over 25 had higher neutralization titers after six months. All participants with very low neutralization titers were offered booster vaccination. The booster vaccination improved the extent and sustainability of antibody responses.
ABSTRACT
BACKGROUND AND OBJECTIVES: The SARS-CoV2 pandemic and the different manifestations of the coronavirus disease 2019 (COVID-19) are a major challenge for health systems worldwide. Medical personnel have a special role in containing the pandemic. The aim of the study was to investigate the SARS-CoV2 IgG antibody prevalence in extraclinical personnel depending on their operational area in the fight against the COVID-19 pandemic. METHODS: On May 28 and 29, 2020, serum samples were taken from 732 of 1183 employees (61.9%) of the professional fire brigade and aid organizations in the city area and tested for SARS-CoV2 IgG antibodies. The employees were divided into four categories according to their type of participation. category 1: decentralized PCR sampling teams, category 2: rescue service, category 3: fire protection, category 4: situation center. Some employees participated in more than one operational area. RESULTS: SARS-CoV2 IgG antibodies were detected in 8 of 732 serum samples. This corresponds to a prevalence of 1.1%. A previous COVID-19 infection was known in 3 employees. In order to make a separate assessment of the other employees possible and to diagnose unknown infections, a corrected collective of 729 employees with 6 SARS-CoV2 antibody detection was considered separately. The prevalence in the corrected collective is 0.82%. After subdividing the collective into areas of activity, the prevalence was low (1: 0.77%, 2: 0.9%, 3: 1.00%, 4: 1.58%). CONCLUSIONS: The seroprevalence of SARS-CoV2 in the study collective is low at 1.1% and 0.82%, respectively. There is an increased seroprevalence in operational areas with a lower risk of virus exposure in comparison to operational areas with a higher risk.
ABSTRACT
BACKGROUND: The suppressive effect of mesenchymal stromal/stem cells (MSCs) on diverse immune cells is well known, but it is unclear whether MSCs additionally possess immunostimulatory properties. We investigated the impact of human MSCs on the responsiveness of primary natural killer (NK) cells in terms of cytokine secretion. METHODS: Human MSCs were generated from bone marrow and nasal mucosa. NK cells were isolated from peripheral blood of healthy volunteers or of immunocompromised patients after severe injury. NK cells were cultured with MSCs or with MSC-derived conditioned media in the absence or presence of IL-12 and IL-18. C-C chemokine receptor (CCR) 2, C-C chemokine ligand (CCL) 2, and the interferon (IFN)-γ receptor was blocked by specific inhibitors or antibodies. The synthesis of IFN-γ and CCL2 was determined. RESULTS: In the absence of exogenous cytokines, trace amounts of NK cell-derived IFN-γ licensed MSCs for enhanced synthesis of CCL2. In turn, MSCs primed NK cells for increased release of IFN-γ in response to IL-12 and IL-18. Priming of NK cells by MSCs occurred in a cell-cell contact-independent manner and was impaired by inhibition of the CCR2, the receptor of CCL2, on NK cells. CD56(bright) NK cells expressed higher levels of CCR2 and were more sensitive to CCL2-mediated priming by MSCs and by recombinant CCR2 ligands than cytotoxic CD56(dim) NK cells. NK cells from severely injured patients were impaired in cytokine-induced IFN-γ synthesis. Co-culture with MSCs or with conditioned media from MSCs and MSC/NK cell co-cultures from healthy donors improved the IFN-γ production of the patients' NK cells in a CCR2-dependent manner. CONCLUSIONS: A positive feedback loop driven by NK cell-derived IFN-γ and MSC-derived CCL2 increases the inflammatory response of cytokine-stimulated NK cells not only from healthy donors but also from immunocompromised patients. Therapeutic application of MSCs or their soluble factors might thus improve the NK function after severe injury.
