Introduction
Immunocompromised patients are at high risk of severe COVID-19. Since
they might not elicit an adequate immune response after vaccination,
passive immunization using ex-vivo produced neutralizing antibodies is
one of the key therapeutic options in such
populations1. Monoclonal anti-spike antibodies have
shown a great risk reduction of hospitalization or death in
immunocompetent patients2,3. However, emerging Omicron
SARS-CoV-2 variants appeared to be completely or partially resistant to
available monoclonal antibodies4. Early treatment with
COVID-19 convalescent plasma (CCP) in unvaccinated immunocompetent
patients has been shown to be associated with a lower risk of
hospitalization5. Therefore, even if monoclonal
antibodies seem associated with a greater risk reduction of disease
progression than CCP, the polyclonal characteristics of CCP might be of
particular interest in the context of emergence of new variants. Early
in the pandemic, high titer CCP has shown some efficacy in B-cell
depleted patients6,7 but little is known on the
efficacy of CCP in immunosuppressed patients infected by Omicron
variant. Here, we report a case series of 75 immunocompromised patients
infected by the BA.1 or BA.2 Omicron SARS-CoV-2 subvariants and treated
with high titer Omicron CCP.