Health-related quality of life and long-term symptoms among patients with non-severe covid-19 - a prospective cohort study.

BACKGROUND: The vast majority of covid-19 patients experience non-severe disease. Nonetheless, long-term symptoms may be common and the impact on quality of life is uncertain. This study aims to examine these aspects in a prospective, longitudinal cohort. METHODS: Non-hospitalised patients with PCR-confirmed covid-19 were prospectively invited to self-report assessments of background data, symptoms and recovery, illness perception (BIPQ) and health-related quality of life (HR-Qol) measured by EQ5D-VAS. RESULTS: 154 patients were included (mean age 46 years, 69% female). The majority of participants (65%) had symptoms for 1-4 weeks and 12% more than 6 months. The most common symptoms were initially malaise, fatigue, headache, fever and cough and the most common long-term symptoms were impaired physical condition, fatigue, anosmia and headache. The BIPQ index had a negative correlation with the EQ5D-VAS score after the infection, but not with long-term symptoms. Mean differences in the EQ5D-VAS score were significantly lower after the infection and patients with long-term symptoms had a more pronounced negative effect in EQ5D-VAS scores. CONCLUSION: We found that most patients with non-severe covid-19 reported symptoms for 1-4 weeks and approximately 10% developed long-term symptoms. Non-severe covid-19 seems to have a negative influence on HR-Qol, especially in patients with long-term symptoms and with a greater burden from the disease. None of the initial symptoms could predict the presence of long-term symptoms.

Dynamics of IgG-avidity and antibody levels after Covid-19.

BACKGROUND: A potentially important aspect of the humoral immune response to Covid-19 is avidity, the overall binding strength between antibody and antigen. As low avidity is associated with a risk of re- infection in several viral infections, avidity might be of value to predict risk for reinfection with covid-19. OBJECTIVES: The purpose of this study was to describe the maturation of IgG avidity and the antibody-levels over time in patients with PCR-confirmed non-severe covid-19. STUDY DESIGN: Prospective longitudinal cohort study including patients with RT-PCR confirmed covid-19. Blood samples were drawn 1, 3 and 6 months after infection. Antibody levels and IgG-avidity were analysed. RESULTS: The majority had detectable s- and n-antibodies (88,1%, 89,1%, N = 75). The level of total n-antibodies significantly increased from 1 to 3 months (median value 28,3 vs 39,3 s/co, p<0.001) and significantly decreased from 3 to 6 months (median value 39,3 vs 17,1 s/co, p<0.001). A significant decrease in the IgG anti-spike levels (median value 37,6, 24,1 and 18,2 RU/ml, p<0.001) as well as a significant increase in the IgG-avidity index (median values 51,6, 66,0 and 71,0%, p<0.001) were seen from 1 to 3 to 6 months. CONCLUSION: We found a significant ongoing increase in avidity maturation after Covid-19 whilst the levels of antibodies were declining, suggesting a possible aspect of long-term immunity.

Detection of Chlamydia pneumoniae-specific antibodies binding to the VD2 and VD3 regions of the major outer membrane protein.

Although Chlamydia pneumoniae is an important human pathogen, the antigens eliciting a specific humoral immune response remain elusive. We scrutinized several recombinant chlamydial surface proteins for species-specific recognition by a panel of human sera previously tested for the presence of anti-C. pneumoniae and anti-C. trachomatis antibodies by microimmunofluorescence and enzyme-linked immunosorbent assay. The 15-kDa cysteine-rich protein (CrpA), porin-b (PorB), 9-kDa outer membrane protein (OMP3), 60-kDa outer membrane protein (OMP2), and four fragments of the major outer membrane protein (MOMP) representing each variable domain (VD) were overexpressed in Escherichia coli, affinity purified, and employed for Western blot analysis. None of the sera tested contained antibodies recognizing PorB and OMP3 of C. pneumoniae. Sera from C. pneumoniae-immune patients cross-reacted with OMP2 of C. trachomatis, and sera from C. trachomatis-immune patients cross-reacted with CrpA of C. pneumoniae, indicating that some of chlamydial surface molecules share antigenic epitopes. In contrast, the VD2, as well as the VD3, regions of the MOMP of C. pneumoniae were only recognized by C. pneumoniae-positive sera, suggesting the existence of species-specific epitopes. The identification of such epitopes of cell surface molecules provides new insights into C. pneumoniae-specific immune responses and may be of value for the improvement of C. pneumoniae-specific diagnostic assay systems based on defined recombinant antigens.