Influenza vaccination to improve outcomes for patients with acute heart failure (PANDA II): a multiregional, seasonal, hospital-based, cluster-randomised, controlled trial in China.

Summary

In this pragmatic cluster-randomized trial across 164 hospitals (n=7771), offering free influenza vaccination before discharge to patients admitted with acute heart failure reduced the 12-month composite of all-cause mortality or any readmission (41.2% vs 47.0%; OR 0.83; p=0.019) and serious adverse events. The strategy was feasible and scalable within routine inpatient care.

Key Findings

• Primary outcome (12-month all-cause mortality or any readmission): 41.2% vs 47.0%; OR 0.83 (95% CI 0.72–0.97); p=0.019
• Serious adverse events lower with vaccination: OR 0.82 (95% CI 0.70–0.96); p=0.013
• Large multicenter, multiseason, cluster design with point-of-care vaccination feasibility

Clinical Implications

Implement standing inpatient vaccination programs for acute HF admissions before discharge to reduce 12-month mortality/readmission, especially in low-uptake settings.

Limitations

• Cluster design may introduce imbalance; potential contamination and varying vaccine uptake
• Generalizability outside China requires validation; composite excludes early events in some strata

Future Directions

Replication in diverse health systems and evaluation of different vaccine strategies (eg, high-dose, adjuvanted) and cost-effectiveness analyses are needed.