Humoral immunity in dually vaccinated SARS-CoV-2-naïve individuals and in booster-vaccinated COVID-19 convalescent subjects

Background The immune response to COVID-19-vaccination differs between naïve vaccinees and those who were previously infected with SARS-CoV-2. Longitudinal quantitative and qualitative serological differences in these two distinct immunological subgroups in response to vaccination are currently not well studied. Methods We investigate a cohort of SARS-CoV-2-naïve and COVID-19-convalescent individuals immediately after vaccination and 6 months later. We use different enzyme-linked immunosorbent assay (ELISA) variants and a surrogate virus neutralization test (sVNT) to measure IgG serum titers, IgA serum reactivity, IgG serum avidity and neutralization capacity by ACE2 receptor competition. Results Anti-receptor-binding domain (RBD) antibody titers decline over time in dually vaccinated COVID-19 naïves whereas titers in single dose vaccinated COVID-19 convalescents are higher and more durable. Similarly, antibody avidity is considerably higher among boosted COVID-19 convalescent subjects as compared to dually vaccinated COVID-19-naïve subjects. Furthermore, sera from boosted convalescents inhibited the binding of spike-protein to ACE2 more efficiently than sera from dually vaccinated COVID-19-naïve subjects. Conclusions Long-term humoral immunity differs substantially between dually vaccinated SARS-CoV-2-naïve and COVID-19-convalescent individuals. Booster vaccination after COVID-19 induces a more durable humoral immune response in terms of magnitude and quality as compared to two-dose vaccination in a SARS-CoV-2-naïve background

Verfahren und Monitordetektor zur Bestimmung der Intensität von gepulster VUV - oder EUV- Strahlung sowie Verwendung eines derartigen Monitordetekors

Hauptanspruch: Verfahren zur Bestimmung der Intensität von hochenergetischer, gepulster VUV- oder EUV-Strahlung mit folgenden Verfahrensschritten: - Durchstrahlung einer mit Gas bei einem definierten Druck <10^-4 hPa gefüllten Wechselwirkungszone (3) in eienr definierten Strahlrichtugn 1 zur Bildung von Photoelektronen und Photoionen,- Beschleunigung der Photoionen und Photoelektronen in einem definierten Winkel zur Strahlrichtung (1) durch ein elektrisches Feld derart, dass dadurch keine Ladungsvervielfachung entsteht, - seperate Detektion der beschleunigten Photoelektronen und der beschleunigten Photoionen und - Bildung eines gemittelten Detektionssignals für die generierten Photoionen als kalibrierbares Signal und eines pulsaufgelösten Detektionssignals für die generierten Photoelektrone

Immunity after COVID-19 and vaccination: follow-up study over 1 year among medical personnel

Background The long-term course of immunity among individuals with a history of COVID-19, in particular among those who received a booster vaccination, has not been well defined so far. Methods SARS-CoV-2-specific antibody levels were measured by ELISA over 1 year among 136 health care workers infected during the first COVID-19 wave and in a subgroup after booster vaccination approximately 1 year later. Furthermore, spike-protein-reactive memory T cells were quantified approximately 7 months after the infection and after booster vaccination. Thirty healthy individuals without history of COVID-19 who were routinely vaccinated served as controls. Results Levels of SARS-CoV-2-specific IgM- and IgA-antibodies showed a rapid decay over time, whereas IgG-antibody levels decreased more slowly. Among individuals with history of COVID-19, booster vaccination induced very high IgG- and to a lesser degree IgA-antibodies. Antibody levels were significantly higher after booster vaccination than after recovery from COVID-19. After vaccination with a two-dose schedule, healthy control subjects developed similar antibody levels as compared to individuals with history of COVID-19 and booster vaccination. SARS-CoV-2-specific memory T cell counts did not correlate with antibody levels. None of the study participants suffered from a reinfection. Conclusions Booster vaccination induces high antibody levels in individuals with a history of COVID-19 that exceeds by far levels observed after recovery. SARS-CoV-2-specific antibody levels of similar magnitude were achieved in healthy, COVID-19-naïve individuals after routine two-dose vaccination

Omicron’s binding to sotrovimab, casirivimab, imdevimab, CR3022, and sera from previously infected or vaccinated individuals

SARS-CoV-2 Omicron is the first pandemic variant of concern exhibiting an abrupt accumulation of mutations particularly in the receptor-binding domain that is a critical target of vaccination induced and therapeutic antibodies. Omicron's mutations did only marginally affect the binding of ACE2, and the two antibodies Sotrovimab and CR3022 but strongly impaired the binding of Casirivimab and Imdevimab. Moreover, as compared with Wuhan, there is reduced serum reactivity and a pronounced loss of competitive surrogate virus neutralization (sVN) against Omicron in naïve vaccinees and in COVID-19 convalescents after infection and subsequent vaccination. Finally, although the booster vaccination response conferred higher titers and better sVN, the effect was nonetheless significantly lower compared with responses against Wuhan. Overall, our data suggest that the antigenicity of Omicrons receptor binding motive has largely changed but antibodies such as Sotrovimab targeting other conserved sites maintain binding and therefore hold potential in prophylaxis and treatment of Omicron-induced COVID-19