Frequent presymptomatic household transmission of influenza A but not influenza B virus

Key Points

• Presymptomatic transmission of influenza A was common in households, unlike influenza B infection.
• The findings indicate that influenza A spreads before symptoms arise, increasing infection risk.
• Observational analysis across multiple households measured viral shedding and timing of symptom onset.
• This highlights the need for strict preventive measures during influenza seasons to limit spread.