Contact Tracing Assessment of COVID-19 Transmission Dynamics in Taiwan and Risk at Different Exposure Periods Before and After Symptom Onset

Study of 100 confirmed COVID-19 cases and 2761 close contacts, reported an overall secondary clinical attack rate of 0.7%. The attack rate was higher among contacts whose exposure to the index case started within 5 days of symptom onset versus those exposed later (1.0% vs 0%).


JAMA Internal Medicine