The effectiveness of interventions to reduce the transmission of acute respiratory infections in care homes: a systematic review.

Background: Care home residents are at high risk from outbreaks of respiratory infections, such as influenza and COVID-19. We conducted a systematic review of randomized controlled trials, to determine which interventions (apart from vaccines) are effective at reducing transmission of acute respiratory illnesses (ARIs) in care homes.

Methods: We searched CINAHL, Medline, Embase and Cochrane for randomized controlled trials (RCTs) of interventions to prevent transmission of ARIs in care homes (excluding vaccines), to April 2023.

Results: A total of 21 articles met inclusion criteria. Two infection control interventions significantly reduced respiratory infections. Oseltamivir significantly reduced risk of symptomatic laboratory-confirmed influenza (OR 0.39, 95%CI 0.16-0.94, three trials), and influenza-like illness (OR 0.50, 95%CI 0.36-0.69), even in a vaccinated population. High dose vitamin D supplementation reduced incidence of ARIs (incidence rate ratio 0.60; 95%CI 0.38-0.94, one trial). Nine other RCTs of vitamin, mineral, probiotic and herbal supplements showed no significant effect.

Conclusion: Transmission of respiratory infections in care homes can be reduced by educational interventions to improve infection control procedures and compliance by staff, by antiviral prophylaxis soon after a case of influenza has been detected, and by supplementation with high-dose Vitamin D3. Further research is needed to confirm the effect of high-dose Vitamin D3.