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The following is a summary of “Evaluation of influenza antiviral prophylaxis for long-term care residents: a systematic review and meta-analysis,” published in the March 2025 issue of Clinical Infectious Diseases by Hanula et al. 

Influenza disproportionately affected long-term care residents, and guidelines recommended antiviral prophylaxis, including oseltamivir or zanamivir, despite limited supporting evidence.  

Researchers conducted a retrospective study to analyze the effectiveness of oseltamivir, zanamivir, and baloxavir prophylaxis for influenza in long-term care.  

They searched Medline, Embase, PubMed, and other databases from inception to August 16, 2023. Observational studies or randomized controlled trials (RCTs) were included if influenza-like illness (ILI) was reported or infection rates in adult long-term care populations receiving prophylaxis. Outcome values were meta-analyzed as intervention-specific pooled proportions (PPs) and risk ratios (RRs) when applicable. The risk of bias was evaluated using the Cochrane risk of bias tool 2.0 and the Joanna Briggs Institute checklist.  

The results showed that 14 studies with 12,672 long-term care residents were included. Oseltamivir and zanamivir had the lowest rates of symptomatic, test-confirmed infections (oseltamivir PP: 0.7%, 95% CI: 0.1-4.7%; zanamivir PP: 3.0%, 95% CI: 0.9-9.4%) and ILI (oseltamivir PP: 2.8%, 95% CI: 1.8-4.3%; zanamivir PP: 3.4%, 95% CI: 1.3-7.2%). No significant differences were found compared to other interventions (ILI PP range: 4.5-6.4%; infection PP range: 4.6-7.9%). Studies directly comparing antivirals to placebo showed no clear benefits despite all RRs being below 1 (0.51-0.75) due to wide 95% CIs.  

Investigators concluded that while oseltamivir or zanamivir showed potential benefit, limited statistical power necessitated further RCTs to confirm the prophylactic effectiveness. 

Source: academic.oup.com/cid/advance-article-abstract/doi/10.1093/cid/ciaf101/8064583