Interleukin-2: meta-analysis of COVID-19 studies

All studies Mortality Hospitalization Serious outcomes RCTs RCT mortality Peer-reviewed All outcomes

Outcome (studies)

Improvement

Relative risk · 95% CI

All studies (2)−5%

Mortality (1)−71%

Hospitalization (1)−4%

RCTs (1)−71%

Late (2)−5%

00.511.5+

← Interleukin-2
reduces riskIncreased
risk →

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c19early.org

October 2026

Interleukin-2 COVID-19 studies

StudyImprovementRR · 95% CIOutcomeTreatmentControlRelative Risk

Zhu (PSM)−4%1.04 · 0.80–1.35hosp. time21 (n)43 (n) Pimenta B.. (RCT)−71%1.71 · 0.33–8.83death3/142/16STRUCK

Late treatment−5%1.05 · 0.81–1.363/352/595% higher risk

Tau² = 0.00, I² = 0.0%, p = 0.71

All studies−5%1.05 · 0.81–1.363/352/595% higher risk

Tau² = 0.00, I² = 0.0%, p = 0.7100.511.52+

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← Interleukin-2
reduces riskInterleukin-2
increases risk →

c19early.org

October 2026

Interleukin-2 COVID-19 mortality results

StudyImprovementRR · 95% CITreatmentControlRelative Risk

Pimenta B.. (RCT)−71%1.71 · 0.33–8.833/142/16STRUCK

Late treatment−71%1.71 · 0.33–8.833/142/1671% higher risk

Tau² = 0.00, I² = 0.0%, p = 0.53

All studies−71%1.71 · 0.33–8.833/142/1671% higher risk

Tau² = 0.00, I² = 0.0%, p = 0.5300.511.52+

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← Interleukin-2
reduces riskInterleukin-2
increases risk →

c19early.org

October 2026

Interleukin-2 COVID-19 hospitalization results

StudyImprovementRR · 95% CIOutcomeTreatmentControlRelative Risk

Zhu (PSM)−4%1.04 · 0.80–1.35hosp. time21 (n)43 (n)

Late treatment−4%1.04 · 0.80–1.3521 (n)43 (n)4% higher risk

Tau² = 0.00, I² = 0.0%, p = 0.78

All studies−4%1.04 · 0.80–1.3521 (n)43 (n)4% higher risk

Tau² = 0.00, I² = 0.0%, p = 0.7800.511.52+

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← Interleukin-2
reduces riskInterleukin-2
increases risk →

c19early.org

October 2026

Interleukin-2 COVID-19 serious outcomes

StudyImprovementRR · 95% CIOutcomeTreatmentControlRelative Risk

Pimenta B.. (RCT)−71%1.71 · 0.33–8.83death3/142/16STRUCK

Late treatment−71%1.71 · 0.33–8.833/142/1671% higher risk

Tau² = 0.00, I² = 0.0%, p = 0.53

All studies−71%1.71 · 0.33–8.833/142/1671% higher risk

Tau² = 0.00, I² = 0.0%, p = 0.5300.511.52+

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← Interleukin-2
reduces riskInterleukin-2
increases risk →

c19early.org

October 2026

Interleukin-2 COVID-19 Randomized Controlled Trials

StudyImprovementRR · 95% CIOutcomeTreatmentControlRelative Risk

Pimenta B.. (RCT)−71%1.71 · 0.33–8.83death3/142/16STRUCK

Late treatment−71%1.71 · 0.33–8.833/142/1671% higher risk

Tau² = 0.00, I² = 0.0%, p = 0.53

All studies−71%1.71 · 0.33–8.833/142/1671% higher risk

Tau² = 0.00, I² = 0.0%, p = 0.5300.511.52+

Rotate screen for more detailsIncrease width for more details

← Interleukin-2
reduces riskInterleukin-2
increases risk →

c19early.org

October 2026

Interleukin-2 COVID-19 RCT mortality results

StudyImprovementRR · 95% CITreatmentControlRelative Risk

Pimenta B.. (RCT)−71%1.71 · 0.33–8.833/142/16STRUCK

Late treatment−71%1.71 · 0.33–8.833/142/1671% higher risk

Tau² = 0.00, I² = 0.0%, p = 0.53

All studies−71%1.71 · 0.33–8.833/142/1671% higher risk

Tau² = 0.00, I² = 0.0%, p = 0.5300.511.52+

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← Interleukin-2
reduces riskInterleukin-2
increases risk →

c19early.org

October 2026

Interleukin-2 COVID-19 peer reviewed studies

StudyImprovementRR · 95% CIOutcomeTreatmentControlRelative Risk

Zhu (PSM)−4%1.04 · 0.80–1.35hosp. time21 (n)43 (n) Pimenta B.. (RCT)−71%1.71 · 0.33–8.83death3/142/16STRUCK

Late treatment−5%1.05 · 0.81–1.363/352/595% higher risk

Tau² = 0.00, I² = 0.0%, p = 0.71

All studies−5%1.05 · 0.81–1.363/352/595% higher risk

Tau² = 0.00, I² = 0.0%, p = 0.7100.511.52+

Rotate screen for more detailsIncrease width for more details

← Interleukin-2
reduces riskInterleukin-2
increases risk →

c19early.org

October 2026

Interleukin-2 COVID-19 outcomes

StudyImprovementRR · 95% CIOutcomeTreatmentControlRelative Risk

Zhu (PSM)−4%1.04 · 0.80–1.35hosp. time21 (n)43 (n) Pimenta B.. (RCT)−71%1.71 · 0.33–8.83death3/142/16STRUCK Pimenta B.. (RCT)−90%1.90 · 0.55–6.57no improv.5/143/16STRUCK

00.511.52+

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← Interleukin-2
reduces riskInterleukin-2
increases risk →