Quantifying H5N1 outbreak potential and control effectiveness in high-risk agricultural populations

Area of Science:

• Epidemiology
• Public Health
• Infectious Disease Modeling

Background:

• Avian influenza (H5N1) poses a global threat, with recent panzootics showing increased spread and host range.
• Spillover events into mammals raise concerns about human-to-human transmission and pandemic potential.
• Current UK public health measures include contact tracing and self-isolation for avian influenza cases.

Purpose of the Study:

• To estimate potential outbreak sizes of H5N1 following bird-to-human spillover.
• To evaluate the effectiveness of contact tracing and self-isolation in managing H5N1 community outbreaks.
• To characterize social contact patterns in an at-risk agricultural population.

Main Methods:

• Utilized data from the Avian Contact Study to characterize contact patterns in an agricultural population.
• Employed a stochastic branching process model to simulate H5N1 outbreak sizes.
• Incorporated realistic social contact data into the modeling framework.

Main Results:

• Most simulated outbreaks were small (0-10 cases).
• Contact tracing and self-isolation reduced average outbreak size from 41 to 7 cases (at R0=1.1), preventing ~80% of infections.
• Control effectiveness decreased with a higher proportion of asymptomatic cases.

Conclusions:

• Contact tracing and self-isolation are effective strategies for preventing zoonotic infections like avian influenza.
• Public awareness, voluntary self-isolation, and surveillance for asymptomatic cases are key for containment.
• These public health interventions can mitigate the impact of H5N1 spillover events.