The silent surge: the under-recognised burden of respiratory syncytial virus, human metapneumovirus, and parainfluenza viruses in adults.

Respiratory syncytial virus (RSV), human metapneumovirus (HMPV), and parainfluenza viruses (PIV) drive substantial morbidity in adults, yet remain underdiagnosed due to diagnostic gaps. While influenza and COVID-19 benefit from rapid triplex antigenic tests and PCR, HMPV and PIV lack routine diagnostics, and RSV testing is underutilised in adults, leading to frequent misdiagnosis as common colds or bacterial infections. This opinion paper highlights the burden of these "forgotten viruses" in elderly and comorbid populations, where RSV and HMPV cause significant hospitalizations. Misdiagnosis fuels cardiovascular complications and antimicrobial resistance through inappropriate antibiotic use. Recent RSV vaccine successes offer a blueprint for HMPV and PIV, but improved diagnostics are critical to guide vaccine strategies and inform prevention efforts. Addressing these gaps can reduce healthcare costs and protect vulnerable populations from these hidden respiratory threats.