SARS-CoV-2 infection rebound among patients receiving antiviral agents, convalescent plasma, or no treatment: a systematic review with meta-analysis.

BACKGROUND

There is some evidence showing rebound of COVID-19 infections in patients treated with nirmatrelvir-ritonavir between 2 and 8 days following cessation of the antiviral treatment. COVID-19 rebound is not unique to patients treated with nirmatrelvir-ritonavir, but is also observed in molnupiravir recipients, in patients who did not receive any antiviral treatment and in patients who received convalescent plasma (CP).

MATERIALS AND METHODS

This was a systematic review with meta-analysis of clinical trials evaluating rates of virologic and clinical rebound in COVID-19 patients receiving antiviral agents, CP or no treatment. Both randomized clinical trials and controlled cohort studies were considered. The methodological quality of trials was assessed using ROB-2 and ROBIN-1 checklists, and the GRADE approach.

RESULTS

Data were available from 16 trials. The occurrence of virologic rebound was more commonly observed among nirmatrelvir recipients than among untreated patients (relative risk [RR]=2.12; 95% confidence interval [CI]: 1.38-3.28; p=0.0007). No differences were observed in the occurrence of virologic rebound between nirmatrelvir-ritonavir and molnupiravir recipients (RR=1.01; 95% CI: 0.71-1.43). Similar rates of virologic rebounds were observed in molnupiravir recipients and untreated patients (RR=1.14; 95% CI: 0.81-1.6). One study in the pre-omicron period compared rates of virologic rebound between patients receiving standard of care with or without CP: no differences were observed between groups (RR=1.04; 95% CI: 0.55-1.99). Rates of clinical rebound were reported in seven trials, five evaluating nirmatrelvir-ritonavir and untreated patients, and two evaluating nirmatrelvir-ritonavir and molnupiravir recipients. No statistically significant differences between groups were observed. For all these comparisons, the certainty of the available evidence was graded as low or moderate.

DISCUSSION

Virologic rebound of COVID-19 infections appears to be mild and self-limited, and was observed more commonly in nirmatrelvir-ritonavir recipients than in untreated patients, but was also observed in patients treated with molnupiravir or CP.