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Breakout Group: Best Methods for Studying Contact Transmission

Breakout Group: Best Methods for Studying Contact Transmission. November 4 , 2010 and November 5, 2010 – Atlanta, GA. “Understanding the Modes of Influenza Transmission” Workshop.

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Breakout Group: Best Methods for Studying Contact Transmission

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  1. Breakout Group: Best Methods for Studying Contact Transmission November 4 , 2010 and November 5, 2010 – Atlanta, GA “Understanding the Modes of Influenza Transmission” Workshop

  2. What are the key questions/ gaps remaining in understanding the contribution of contact transmission to the spread of influenza among humans?

  3. Contact Transmission Breakout Group: Remaining Key Questions/ Gaps • Methodological issues • PCR identification and quantification VERSUS culture viability VERSUS human infectivity • Lack of evidence for contribution of contact transmission on human influenza: • Infectious dose • Effect of underlying immunity • Survival on various surfaces, especially hands • Role of eyes, lips, nose, mouth exposure • Environmental microbiology of influenza • Level of contamination of various surfaces • Significance of heavily contaminated environments • Contribution of humidity, temperature, uv, matrix, to survival

  4. What are the best study designs and their pro’s/ con’s? What study designs would be best for understanding the contribution of contact transmission to the other transmission routes?

  5. Contact Transmission Breakout Group: Best Study Design and pro’s/ con’s • Survival of virus on surfaces, especially hands as a function of temperature, humidity, matrix, uv. • Pros: Basic environmental microbiology needed to inform human studies • Cons: Does not prove role in contact transmission in humans • Human inoculation experiments, focusing on roles of lips, eyes, nose, mouth as entry portals • Pros: Address major gaps • Cons: Not demonstrate role in natural infection. Ethical concerns. Confounded by differences in strain, concentration, matrix. Expensive. • Suggestion: Do first in ferrets, especially eye inoculation.

  6. Contact Transmission Breakout Group: Best Study Design and pro’s/ con’s • Determine environmental burden of influenza – laboratory & field studies • Pros: Inform human studies and models • Cons: Does not prove contact transmission • Human challenge studies: • Pros: Can selectively block different modes of transmission; human infections, can study interventions; able to control for confounders better than field studies • Cons: Expensive, ethical issues, limited virus strains, not natural infections • Suggestion: Use naturally infected donors, but logistically very problematic

  7. Contact Transmission Breakout Group: Best Study Design and pro’s/ con’s • Hand washing studies: • Pros: Best way of investigating value of intervention • Cons: Does not effectively address role of contact transmission. Lots of confounders. Lots of conflicting results. Lack of positive result does not discard contact transmission.

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