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. 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. 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. 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. 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.

A feared cause of bacteraemia with Gram-positives is infective endocarditis. Risk stratification scores can aid clinicians in determining the risk of endocarditis. Six proposed scores for the use i...

Patients who suffer from long-term symptoms of COVID-19, described as post COVID-19 condition, are a new and large group of patients. There is a lack of knowledge concerning health experiences in this patient group. The aim of this study was to explore patients’ health experiences of post COVID-19 condition. Data collection was performed through 14 semi-structured interviews. The qualitative content analysis resulted in six sub-categories, three categories, and an overall theme. Patients experienced symptoms of varying duration—ranging from 5–21 months. The results showed that patients’ health experiences of post COVID-19 condition moved between uncertainty and new insights. This was shown by patients experiencing: (1) loss of abilities, including losing smell and taste and lacking energy, (2) loss of control, including being foreign to oneself and seeking answers, and (3) revaluation of life, including accepting the transformed body and prioritizing health. This study illustrates that patients living with post COVID-19 condition need to be treated with flexibility, based on each individual’s unique challenges and experiences of the symptoms and the consequences for their health.

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 ...

Background: Serological response is an important aspect of COVID‐19, especially for evaluation of vaccine effect and risk of severe infection. The gold standard to assess this is analysis of neutralization capacity, but such assays are not widely available, with antibody levels often used as an approximation of the neutralizing ability. Avidity index is a measure of antibody function and avidity maturation contributes to long‐lasting immunity. Objectives: To evaluate if the avidity index gives a better estimation of the neutralizing ability compared with anti‐spike IgG levels and to compare the immune response between infection and vaccination against SARS‐CoV‐2. Study Design: Serum samples from prospectively included patients with either PCR‐confirmed COVID‐19 or COVID‐19‐naïve after vaccination were analyzed for anti‐spike IgG, avidity index, and neutralizing titer at 1, 3, and 6 months after infection or vaccination. Results: A significant correlation between anti‐spike IgG level and neutralization titer was found (Spearman r _s = 0.88, p < 0.001), but for the avidity index, the correlation was lower (Spearman r _s = 0.62, p < 0.001). Anti‐spike IgG level, avidity index, and neutralization titer were significantly higher in the vaccine cohort. Natural infection failed to yield high‐avidity antibodies. Over time, the antibody levels and neutralization titer declined in both the vaccine and infection cohorts. Conclusion: Anti‐spike IgG levels can be used as an estimation of the neutralizing titer, with the avidity index not contributing to a better estimation. There is a stronger initial immune response after vaccination, compared with natural infection. However, specific antibody levels decline over time, highlighting the importance of vaccine boosters.

Background: Serological response is an important aspect of COVID-19, especially for evaluation of vaccine effect and risk of severe infection. The gold standard to assess this is analysis of neutralization capacity, but such assays are not widely available, with antibody levels often used as an approximation of the neutralizing ability. Avidity index is a measure of antibody function and avidity maturation contributes to long-lasting immunity.