For pertussis, past smoking was associated with a seropositive titer (anti-PT ≥ 5 IU/mL) (OR vs. non-smoking: 1.4; 1.1–2.0; p = 0.03) and with a titer indicative for previous infection or vaccination (anti-PT ≥ 50 IU/mL) (OR vs. non-smoking:1.8; 1.0–3.5; p = 0.05) and active smoking was associated with titers indicative for a recent infection or vaccination (anti-PT ≥ 100IU/mL) (OR vs. non-smoking: 4.5;1.2–18.3; p = 0.03). The gene discussed is F2; the disease is infection.