Insights from respiratory virus co-infections

Table 1 Virological interactions in co-infections

Co-infection combination	Interaction type	Impact on disease progression
Dengue virus + secondary virus	Competitive	Increased risk of severe dengue outcomes (DHF, DSS)
RSV + influenza	Cooperative/competitive	Prolongs disease, increases severity and duration in some cases
RSV + other respiratory viruses (e.g., hMPV)	Varies; neutral in some models	Little to no increase in pathogenicity in some animal models

DHF: Dengue hemorrhagic fever; DSS: Dengue shock syndrome; hMPV: Human metapneumovirus; RSV: Respiratory syncytial virus.