Due to the lower virulence of circulating Omicron variants and the high seroprevalence of
anti-SARS-CoV-2 antibodies, the incidence of cases and deaths related to the SARS-CoV-2
virus has significantly decreased in recent months worldwide. However, these infections
remain a major public health problem in severely immunocompromised patients, who have
decreased vaccine efficacy and are at higher risk of persistent SARS-CoV-2 viral
shedding, relapses, secondary invasive fungal infection, intensive care unit
hospitalization, and death than non-immunocompromised patients.

The research concerns adult patients at very high risk of severe SARS-CoV-2 disease,
suffering from SARS-CoV-2 having resulted in hospitalization in a center participating in
the study in France between June 1, 2023 and April 1, 2024 and having received mono- or
dual therapy with nirmatrelvir/ritonavir or remdesivir in order to carry out an
evaluation of direct antiviral treatments against SARS-CoV-2 in these immunocompromised
patients suffering from Covid-19.

Identifying an effective anti-SARS-CoV-2 therapeutic strategy is a real challenge in
severely immunocompromised patients because clinicians are faced with chronic carriage
and serious complications in these patients, as well as drug interactions with
immunosuppressive treatments, the emergence of resistance and the absence of
recommendations.

The data currently available in the literature remain heterogeneous and sometimes without
sufficient level of evidence. However, some teams have reported in this population the
efficacy of repeated or prolonged treatment with nirmatrelvir/ritonavir or even
multitherapies combining several antiviral treatments and/or combinations of monoclonal
antibodies on persistent carriage of the virus. Thus, some centers recommend prolonged
antiviral treatments combining 5 to 10 days of remdesivir with 10 days of
nirmatrelvir/ritonavir.

Nirmatrelvir/ritonavir and remdesivir are the currently available antiviral therapies
that are still effective against circulating Omicron virus subvariants. It therefore
seems important to have more data on their efficacy in monotherapy, dual therapy, or in
the case of prolonged treatment.

The study consists of collecting patient care data from the medical record. Patients will
be identified by practitioners at each participating French center.