Tdap vaccination status does not change the approach to evaluating postexposure prophylaxis when HCWs are exposed to pertussis. Tdap vaccines have an uncertain role in the prevention of transmission of pertussis and herd protection. Antipertussis antibody levels begin to decline precipitously after the first year following a single Tdap vaccination. Healthcare facilities should follow the post-exposure prophylaxis protocol for pertussis exposure recommended by CDC regardless of a HCW’s vaccination status (see www.cdc.gov/pertussis/pep.html). HCW can either receive postexposure prophylaxis or be carefully monitored for 21 days after pertussis exposure. Health care personnel should be treated with antibiotics at the onset of signs and symptoms of pertussis and excluded from work for the first 5 days while receiving appropriate antibiotics. CDC supports targeting postexposure antibiotic use to people at high risk of developing severe pertussis, as well as people who will have close contact with others at high risk of developing severe pertussis.