Follow-up SARS-CoV-2 serological study of a health care worker cohort following COVID-19 booster vaccination

BACKGROUND

Studies have shown that Omicron breakthrough infections can occur at higher SARS-CoV-2 antibody levels compared to previous variants. Estimating the magnitude of immunological protection induced from COVID-19 vaccination and previous infection remains important due to varying local pandemic dynamics and types of vaccination programmes, particularly among at-risk populations such as health care workers (HCWs). We analysed a follow-up SARS-CoV-2 serological survey of HCWs at a tertiary COVID-19 referral hospital in Germany following the onset of the Omicron variant.

METHODS

The serological survey was conducted in January 2022, one year after previous surveys in 2020 and the availability of COVID-19 boosters including BNT162b2, ChAdOx1-S, and mRNA-1273. HCWs voluntarily provided blood for serology and completed a comprehensive questionnaire. SARS-CoV-2 serological analyses were performed using an Immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA). Antibody levels were reported according to HCW demographic and occupational characteristics, COVID-19 vaccination and SARS-CoV-2 infection history, and multivariate linear regression was used to evaluate these associations.

RESULTS

In January 2022 (following the fourth COVID-19 wave in Germany including the onset of the Omicron variant), 1482/1517 (97.7%) HCWs tested SARS-CoV-2 seropositive, compared to 4.6% in December 2020 (second COVID-19 wave). Approximately 80% had received three COVID-19 vaccine doses and 15% reported a previous laboratory-confirmed SARS-CoV-2 infection. SARS-CoV-2 IgG geometric mean titres ranged from 335 (95% Confidence Intervals [CI]: 258-434) among those vaccinated twice and without previous infection to 2204 (95% CI: 1919-2531) among those vaccinated three times and with previous infection. Heterologous COVID-19 vaccination combinations including a mRNA-1273 booster were significantly associated with the highest IgG antibody levels compared to other schemes. There was an 8-to 10-fold increase in IgG antibody levels among 31 HCWs who reported a SARS-CoV-2 infection in May 2020 to January 2022 after COVID-19 booster vaccination.

CONCLUSIONS

Our findings demonstrate the importance of ongoing COVID-19 booster vaccination strategies in the context of variants such as Omicron and despite hybrid immunity from previous SARS-CoV-2 infections, particularly for at-risk populations such as HCWs. Where feasible, effective types of booster vaccination, such as mRNA vaccines, and the appropriate timing of administration should be carefully considered.

Longitudinal SARS-CoV-2 seroepidemiological investigation among healthcare workers at a tertiary care hospital in Germany

Background

SARS-CoV-2 cases in Germany increased in early March 2020. By April 2020, cases among health care workers (HCW) were detected across departments at a tertiary care hospital in Berlin, prompting a longitudinal investigation to assess HCW SARS-CoV-2 serostatus with an improved testing strategy and associated risk factors.

Methods

In May/June and December 2020, HCWs voluntarily provided blood for serology and nasopharyngeal/oropharyngeal (NP/OP) samples for real-time polymerase chain reaction (PCR) and completed a questionnaire. A four-tiered SARS-CoV-2 serological testing strategy including two different enzyme-linked immunosorbent assays (ELISA) and biological neutralization test (NT) was used. ELISA-NT correlation was assessed using Pearson’s correlation coefficient. Sociodemographic and occupational factors associated with seropositivity were assessed with multivariate logistic regression.

Results

In May/June, 18/1477 (1.2%) HCWs were SARS-CoV-2 seropositive, followed by 56/1223 (4.6%) in December. Among those tested in both, all seropositive in May/June remained seropositive by ELISA and positive by NT after 6 months. ELISA ratios correlated well with NT titres in May/June (R = 0.79) but less so in December (R = 0.41). Those seropositive reporting a past SARS-CoV-2 positive PCR result increased from 44.4% in May/June to 85.7% in December. HCWs with higher occupational risk (based on profession and working site), nurses, males, and those self-reporting COVID-19-like symptoms had significantly higher odds of seropositivity.

Conclusions

This investigation provides insight into the burden of HCW infection in this local outbreak context and the antibody dynamics over time with an improved robust testing strategy. It also highlights the continued need for effective infection control measures particularly among HCWs with higher occupational risk.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07057-3.

Living Donor Kidney Transplantation From the Elderly Donor

PURPOSE

The organ shortage has led to increasing acceptance of living donation in all transplant centers. Although the risk of impaired long-term outcome seems to be greater using elderly donors, these organs are not generally refused for transplantation. We report our experience with 25 living donor kidney transplantations from donors older than 60 years.

METHODS

Between 1995 and 2004, 124 living donor procedures were performed in our center from 83 related and 41 unrelated donors. Twenty-five donors (19 female, 6 male) were 60 years or older (mean, 65.3 +/- 3.9 years). The recipient included (10 females and 15 males) showed a higher degree of variance in age (46.1 +/- 14.6 years). The immunosuppressive protocol was cyclosporine (CyA)-based regimen in related cases and tacrolimus-based in unrelated cases.

RESULTS

We transplanted 16 left and 9 right kidneys from older donors. The mean cold ischemia time was 171 +/- 64 minutes with a second warm ischemia time of 24 +/- 6 minutes. Severe arteriosclerosis made vascular reconstruction by graft interposition necessary in two recipients. The acute rejection rate was 20%. Two patients (8%) required dialysis in the early postoperative course, whereas initial function was excellent in 22 patients (88%). The mean serum creatinine concentration after 12 months was 1.6 +/- 0.3 mg/dL (n = 24) and 2.0 +/- 0.7 mg/dL (n = 16) at 4 years. In comparison, the mean creatinine concentration after 4 years in donors under 60 years was 1.6 +/- 0.9 mg/dL. Our analysis showed no significant difference in long-term graft function comparing young versus old donors in the setting of living donor transplants.

CONCLUSION

Using living donors older than 60 years for transplantation is a feasible and safe option. The difference in long-term creatinine between young and old donors was not significant.

Prevalence of cardiac beta-myosin heavy chain gene mutations in patients with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a frequent, autosomal-dominant cardiac disease and manifests predominantly as left ventricular hypertrophy. Mutations in the cardiac beta-myosin heavy chain gene (MYH7) are responsible for the disease in about 30% of cases where mutations were identified. We clinically evaluated a large group of 147 consecutive HCM patients from three cardiology centers in Germany, Poland, and Kyrgyzstan according to the same protocol. The DNA of the patients was systematically analyzed in the whole coding region of the MYH7 gene using PCR, single-strand conformation polymorphism analysis, and automated sequencing. Eleven different missense mutations (including seven novel ones) in 11 unrelated patients were identified, showing a mutation frequency of 7.5% in the study population. We further examined the families of five patients (three of German, one of Polish, and one of Kyrgyz origin) with 32 individuals in total. We observed a clear, age-dependent penetrance with onset of disease symptoms in the fourth decade of life. Genotype-phenotype correlations were different for each mutation, whereas the majority was associated with an intermediate/malign phenotype. In conclusion, we report a systematic molecular screening of the complete MYH7 gene in a large group of consecutive HCM patients, leading to a genetic diagnosis in 38 individuals. Information about the genotype in an individual from one family could be very useful for the clinician, especially when dealing with healthy relatives in doubt of their risk about developing HCM. The increasing application of genetic screening and the increasing knowledge about genotype-phenotype correlations will hopefully lead to an improved clinical management of HCM patients.

Modelling gradient elution of bioactive multicomponent systems in non-linear ion-exchange chromatography

A theoretical framework for the ion-exchange behaviour of bioactive substances in non-linear ion-exchange chromatogaphy is described. The aim of the study was the creation of a model basis to support a process design for production-scale ion-exchange chromatography. The theory can be applied to a whole variety of biological substances, such as amino acids, polysaccharides, peptides and proteins and either isocratic or gradient elution can be carried out. The influence of the eluent concentration on the ion-exchange as well as on the characteristic charge was considered. Experimental measurements showed a strong non-linear ion-exchange equilibrium with a transition from a Langmuir-type to a sigmoidal isotherm at higher eluent concentrations. Hereby, the compound binds to the surface though it is not ionic. Therefore, the model considered the possibility of ion-exchange as well as adsorption. A simplified distribution of the counter-ions based on the Gouy-Chapman theory with a discrete distribution of the counter-ions was used. The theory was extended by a selectivity in the double layer to allow specific adsorption. Calculations of adsorption-elution cycles showed, in agreement with the experimental observations, the development of non-linear elution profiles with a desorption fronting. As a result, the column loading and the eluent concentration were varied. The effect of contaminants, in this case sodium ions, was investigated and included in the model. Finally, the model was extended to multicomponent systems to investigate the effect of side components on the retention behaviour. The development of the characteristic elution profiles and the effect of the column loading on the separation are discussed. Calculated concentration profiles along the column at discrete time steps were used to reveal the influence of side components and the underlying separation mechanism. The simulations provided a new insight into the phenomena involved in biochromatography and make convenient design concepts at least doubtful as the separation is in this case mainly determined by the loading step and not by the choice of the elution gradient.

Desorption of a fixed-bed adsorber by ultrasound

Adsorption processes offer the possibility to remove trace impurities of liquid process streams. An important step in adsorption processes is the regeneration of the adsorbent as it does not only affect the adsorption-desorption cycle but also the expenses of the following process steps. In this study, various desorption experiments of a loaded polymeric resin have been conducted. They were performed with cold and hot water as well as with ultrasound at different frequencies and intensities. The results indicate, that an important factor of ultrasound enhanced desorption is the temperature rise due to ultrasonication. But as regeneration is more effective at higher frequencies even though temperatures inside the column are lower, another ultrasonic effect occurs during ultrasonic desorption.