Pathogenic microorganism monitoring and traceability exploration of medical waste disposal routes in children's hospital

OBJECTIVE: Due to the lack of effective monitoring of microbial spectrum of medical waste collection, transport, storage and transfer path, as well as the evaluation of disinfection effects in medical institutions, this study aimed to explore the microenvironment, prevention and control difficulties and management opinions of medical waste disposal path through the microbial analysis of the medical waste disposal path in model departments. METHODS According to the standard process, the environmental samples at different time periods before and after the disinfection of the medical waste disposal path in the model department were collected and analyzed. The drug resistance and molecular typing traceability of important pathogens were analyzed. And the dynamic effect of the whole path application of the disinfection scheme for medical waste disposal in the model department were evaluated. Efficient frequency and application effect of disinfection of and hygiene of relevant places and gloves were evaluated through environmental monitoring before and after disinfection. RESULTS Most of the isolated strains were environmental microorganisms, Acinetobacter baumannii, Pseudomonas aeruginosa, Streptococcus pneumoniae, Enterococcus faecalis and Enterococcus faecium were also isolated, and a multidrug-resistant A. baumannii strain was identified. Through typing and tracing the source, the multiple strains of A. Baumannii were found to be of different genetic origins and the two strains were from the same clonal line. Using original detection technology, no contamination of Salmonella and Shigella was found in the path. The new coronavirus and norovirus were not detected. However, the environmental pollution of rotavirus was obvious. CONCLUSION The risk of random transmission of rotavirus cannot completely solved by existing hand-sterilized regents. Timely or even frequent replacement of gloves is a simple solution in the workflow. The sterilized medical waste transfer vehicles are likely to become the pollution source of rotavirus after passing through a certain medical waste path. The medical waste disposal personnel should replace the rotating vehicle in time before entering other wards. In addition, due to the weak professional ability of cleaners, simple and easy process guidelines is the most effective solution at present.

mRNA vaccines induce rapid antibody responses in mice.

mRNA vaccines can be developed and produced quickly, making them prime candidates for immediate outbreak responses. Furthermore, clinical trials have demonstrated rapid protection following mRNA vaccination. Thus, we sought to investigate how quickly mRNA vaccines elicit antibody responses compared to other vaccine modalities. We first compared the immune kinetics of mRNA and DNA vaccines expressing SARS-CoV-2 spike in mice. We observed rapid induction of antigen-specific binding and neutralizing antibodies by day 5 following mRNA (4 µg/mouse), but not DNA (50 µg/mouse), immunization. Comparing innate responses hours post immunization, the mRNA vaccine induced increased levels of IL-5, IL-6, and MCP-1 cytokines which maybe promoting humoral responses downstream. We then evaluated the immune kinetics of an HIV-1 mRNA vaccine in comparison to DNA, protein, and rhesus adenovirus 52 (RhAd52) vaccines of the same HIV-1 envelope antigen in mice. Again, induction of envelope-specific antibodies was observed by day 5 following mRNA vaccination, whereas antibodies were detected by day 7-14 following DNA, protein, and RhAd52 vaccination. Thus, eliciting rapid humoral immunity may be a unique and advantageous property of mRNA vaccines for controlling infectious disease outbreaks.

Optimization of non-coding regions for a non-modified mRNA COVID-19 vaccine.

The CVnCoV (CureVac) mRNA vaccine for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) was recently evaluated in a phase 2b/3 efficacy trial in humans1. CV2CoV is a second-generation mRNA vaccine containing non-modified nucleosides but with optimized non-coding regions and enhanced antigen expression. Here we report the results of a head-to-head comparison of the immunogenicity and protective efficacy of CVnCoV and CV2CoV in non-human primates. We immunized 18 cynomolgus macaques with two doses of 12 µg lipid nanoparticle-formulated CVnCoV or CV2CoV or with sham (n = 6 per group). Compared with CVnCoV, CV2CoV induced substantially higher titres of binding and neutralizing antibodies, memory B cell responses and T cell responses as well as more potent neutralizing antibody responses against SARS-CoV-2 variants, including the Delta variant. Moreover, CV2CoV was found to be comparably immunogenic to the BNT162b2 (Pfizer) vaccine in macaques. Although CVnCoV provided partial protection against SARS-CoV-2 challenge, CV2CoV afforded more robust protection with markedly lower viral loads in the upper and lower respiratory tracts. Binding and neutralizing antibody titres were correlated with protective efficacy. These data demonstrate that optimization of non-coding regions can greatly improve the immunogenicity and protective efficacy of a non-modified mRNA SARS-CoV-2 vaccine in non-human primates.

Viral load and disease severity in COVID-19.

The relationship between COVID-19 severity and viral load is unknown. Our objective was to assess the association between viral load and disease severity in COVID-19. In this single center observational study of adults with laboratory confirmed SARS-CoV-2, the first positive in-hospital nasopharyngeal swab was used to calculate the log10 copies/ml [log10 copy number (CN)] of SARS-CoV-2. Four categories based on level of care and modified sequential organ failure assessment score (mSOFA) at time of swab were determined. Median log10CN was compared between different levels of care and mSOFA quartiles. Median log10CN was compared in patients who did and did not receive influenza vaccine, and the correlation between log10CN and D-dimer was examined. We found that of 396 patients, 54.3% were male, and 25% had no major comorbidity. Hospital mortality was 15.7%. Median mSOFA was 2 (IQR 0-3). Median log10CN was 5.5 (IQR 3.3-8.0). Median log10CN was highest in non-intubated ICU patients [6.4 (IQR 4.4-8.1)] and lowest in intubated ICU patients [3.6 (IQR 2.6-6.9)] (p value < 0.01). In adjusted analyses, this difference remained significant [mean difference 1.16 (95% CI 0.18-2.14)]. There was no significant difference in log10CN between other groups in the remaining pairwise comparisons. There was no association between median log10CN and mSOFA in either unadjusted or adjusted analyses or between median log10CN in patients with and without influenza immunization. There was no correlation between log10CN and D-dimer. We conclude, in our cohort, we did not find a clear association between viral load and disease severity in COVID-19 patients. Though viral load was higher in non-intubated ICU patients than in intubated ICU patients there were no other significant differences in viral load by disease severity.