This systematic review examined effective ways to prevent respiratory infections like flu and COVID-19 in care homes where elderly residents live. The researchers found that antiviral medications like oseltamivir can halve the risk of influenza even in vaccinated residents if given within 7 days of detecting a case. High-dose vitamin D supplementation (100,000 IU monthly) reduced respiratory infection risk by 40%. Educational programs to improve staff hygiene practices showed mixed results, while other supplements like probiotics did not significantly help.