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. 2024 May 14;13(6):1177–1198. doi: 10.1007/s40121-024-00976-5

Table 2.

Summary of study characteristics

Citation Locationa Study period Dominant variant(s) Relevant analysis population (N) Risk level of study population Prior immunity (%) MOV treatment initiation window Approach to confounder adjustment
Arbel (2022) [29]b, c Israel [41] 16 Jan–31 Mar 2022 Omicron (BA.1)

40–64 years of age

MOV: 224

Control: 6075

 ≥ 65 years of age

MOV: 845

Control: 12,724

 ≥ 40 years of age

High risk for progression to

severe disease

Not eligible for NMV/r due to DDI or impaired kidney function

Documented prior infection and/or ≥ 2 vaccine doses

MOV: 93

Control: 92

 ≤ 5 days after positive test Cox proportional hazards model with time-varying covariates for treatment assignment to address immortal time bias
Bajema (2022) [30, 38]d US [15] 1 Jan–31 July 2022 Omicron

MOV: 3504

Control: 3504

 ≥ 18 years of age

High risk for progression to severe disease

 ≥ 1 vaccine dose

MOV: 85.6

Control: 84.8

 < 10 days after positive test

Target trial emulation framework

Exact and propensity score-matched cohorts

Controls assigned index date same number of days after positive test as the treatment initiation date of matched MOV-treated individual to address immortal time bias

Evans (2023) [31]e UK [22] 16 Dec 2021–22 Apr 2022 Omicron (BA.1, BA.2)

MOV: 359

Control: 4973

At highest risk for

hospitalization/death

 ≥ 1 vaccine dose

Treated: 98.2f

Control: 95.6

 ≤ 7 days after positive test Cox proportional hazards model with time-varying covariate for treatment assignment to address immortal time bias
Najjar-Debbiny (2023) [32]e Israel [41] 1 Jan–28 Feb 2022 Omicron

MOV: 2661

Control: 2661

 ≥ 18 years of age

 ≥ 1 comorbidity or condition associated with high risk for severe disease

 ≥ 2 vaccine doses with most recent dose 7–180 days before diagnosis

MOV: 74.6

Control: 76.1

 ≤ 5 days after positive test

Propensity score-matched cohorts

Cox proportional hazards model

Paraskevis (2023) [33]b, c Greece [42] 2 Feb–5 Mar 2022 Omicron (BA.1, BA.2)

MOV: 4240

Control: 4240

 ≥ 65 years of age

Risk factors for progression to severe disease

 ≥ 1 vaccine dose

MOV: 87.4

Control: 79.7

 ≤ 3 days after

symptom

onset or

positive test

Matched cohorts (by age and week of SARS-CoV-2 infection diagnosis); not adjusted for comorbidities due to unavailability of data for control group
Wai (2023) [34]e Hong Kong [18] 22 Feb–31 Mar 2022 Omicron

MOV: 5345

Control: 23,430

 ≥ 60 years of age or < 60 years of age with ≥ 1 chronic disease NR  ≤ 7 days after attending participating outpatient clinic

Inverse probability of treatment weighting-adjusted Cox proportional

Model

Immortal time bias was not accounted for

Wong (2022) [35]e Hong Kong [18] 26 Feb–26 Jun 2022 Omicron (BA.2.2)

MOV: 4983

Control: 49,234

 ≥ 60 years of age or ≥ 18 years of age with risk factors for progression to severe disease

Fully vaccinatedg

MOV: 16.1

Control: 12.4

 ≤ 5 days after positive test

Propensity score-matched cohorts with Cox proportional hazards model in retrospective cohorts

Time-varying covariate for treatment assignment to address immortal time bias

Conditional logistic regression for case–control sensitivity analysis

Xie (2023) [36]b, e US [15] 5 Jan–20 Oct 2022

Omicron

(BA.1, BA.2, BA.5)

MOV: 7818

Control: 78,180

 ≥ 1 risk factor

for progression to

severe disease

 ≥ 1 vaccine dose

MOV: 85.8

Control: 82.6

 ≤ 5 days after positive test

Target trial emulation framework

Propensity score-matched cohorts

Clone method with inverse probability of censoring weighting, which also addressed immortal time bias

Yip (2023) [37]e Hong Kong [18] 16 Feb–31 Mar 2022 Omicron

MOV: 4798

Control: 4758

Elderly (not defined) or high-risk with incomplete vaccination

Complete vaccination: population rateh

MOV: 36.1

Control: 55.9

 ≤ 5 days after positive test Cox proportional hazards model with propensity score adjustment

DDI drug–drug interaction, MOV molnupiravir, NMV/r nirmatrelvir/ritonavir, NR not reported, UK United Kingdom, US United States

‘Control’ defined as individuals not receiving any approved treatment for COVID-19 and used as comparator group for molnupiravir-treated arm

aReferences are to the guidelines for the use of molnupiravir in each location

bIdentified via supplemental literature surveillance

cPre-print

dIdentified as a pre-print and subsequently published as a peer-reviewed article with updated study period and results; the peer-reviewed version was included in the SLR

ePeer-reviewed study

fA combined prior immunity percentage was reported for all individuals receiving any treatment (molnupiravir, nirmatrelvir/ritonavir, and sotrovimab arms)

gDefined as ≥ 2 doses of BNT162b2 vaccine or ≥ 3 doses of Vero Cell or CoronaVac vaccine. The time since last vaccine dose was also measured

hDefined as ≥ 2 doses of BNT162b2 vaccine or ≥ 3 doses of CoronaVac vaccine. Vaccination data were available at a population-level; background vaccination rate was defined for each participant as the corresponding population vaccination rate on index date for individuals of the same age and gender