TOPLINE:

Among patients with COVID, the use of inosine pranobex (IP), an immunomodulatory agent with antiviral properties, was associated with a more than 20% reduction in the risk for mortality during the pre-Omicron period and with a more than 60% reduction in the risk during the Omicron period.

METHODOLOGY:

• Researchers conducted a retrospective study, analyzing data of all patients with COVID in the Czech Republic to determine the effect of using IP on the risk for COVID-specific mortality, with the analysis divided into the pre-Omicron (March 2020 to December 2021) and Omicron (January 2022 to December 2023) periods.
• They analyzed data of 67,841 IP recipients (42,346 patients in the pre-Omicron period and 25,495 in the Omicron period) matched with 135,682 control individuals (84,692 patients in the pre-Omicron period and 50,990 in the Omicron period), over a follow-up duration of 3 months post-diagnosis.
• The intervention group received IP at 50 mg/kg of body weight daily, administered in three to four evenly divided doses, with a maximum daily dose of 4 g; the therapy was initiated no earlier than 5 days before and no later than 5 days after a positive COVID test.
• The primary outcome was the between-group difference in the case fatality rate (CFR) within 3 months following a diagnosis of COVID, and the secondary outcome was the effectiveness of IP as a standalone therapy vs an adjunctive therapy to targeted COVID agents.

TAKEAWAY:

• During the pre-Omicron period, the CFRs in the intervention and control groups were 1.65% and 2.11%, respectively (relative risk [RR], 0.78; P < .0001), representing a 22% relative reduction in the risk for mortality.
• In the Omicron period, the CFRs in the intervention and control group were 0.13% and 0.35%, respectively (RR, 0.35; P < .0001), indicating a 65% relative reduction in the risk for mortality.
• In patients who received no additional treatment during the Omicron period, the CFR was 0.09% (23/24,613) in the intervention group compared with 0.42% (205/49,226) in the control group (RR, 0.22; P < .001), indicating a 78% relative reduction in the risk for mortality.
• Among patients who received other COVID treatments during the Omicron period, no significant difference in the risk for mortality was observed between groups.

IN PRACTICE:

“[Our] findings suggest a possible protective effect of IP, particularly in patients without access to, or indication for, other treatments,” the authors wrote.

SOURCE:

This study was led by Dalibor Veselý, Charles University, Prague, Czech Republic. It was published online on March 31, 2026, in International Journal of Infectious Diseases.

LIMITATIONS:

The study lacked data on initial symptoms and diagnostic test results. It did not capture information on other in‑hospital or outpatient co‑interventions, such as nontargeted medications or oxygen therapy. Also, treatment allocation was not randomized, and prescribing was concentrated among higher‑risk patients.

DISCLOSURES:

This study was supported by the institutional program of Charles University — Cooperatio. The authors declared having no competing interests.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.