Nirmatrelvir/ritonavir for COVID-19: an overview of systematic reviews

A reappraisal of the validity of the conclusions of systematic reviews (SRs) related to nirmatrelvir/ritonavir for the treatment of COVID-19.

An overview of SRs (umbrella review). The methodological quality of the SRs was assessed using the AMSTAR 2 checklist; quality of the evidence from the trials included in each SR was appraised following the GRADE approach.

Sixteen SRs with meta-analysis published between 2020 and 2023 were included in this overview. The SRs reported data from 108 overlapping reports, based on 43 individual primary studies [3 randomized clinical trials (RCTs), 40 non-RCTs]. In outpatient settings the use of nirmatrelvir/ritonavir reduced overall mortality, hospital admission and progression of disease compared with controls (from moderate to low certainty of evidence); nirmatrelvir/ritonavir reduced mortality, hospital admission and progression of disease in both immunized and non-immunized patients. No differences in the occurrence of any adverse events between groups were observed in the large majority of SRs; serious adverse events, including adverse events requiring discontinuation of treatment, were reported with lower prevalence in nirmatrelvir recipients compared with controls (from low to moderate certainty of evidence).

There is low to moderate certainty of evidence from SRs that nirmatrelvir/ritonavir reduces mortality, clinical progression and hospitalization rate in COVID-19 patients compared with controls, without increasing the occurrence of overall and serious adverse events. Based on the overall methodological assessment, on average we can have high confidence in the quality of results generated by the SRs.