Lessons for preparedness and reasons for concern from the early COVID-19 epidemic in Iran.

Introduction: Many countries with an early outbreak of SARS-CoV-2 struggled to gauge the size and start date of the epidemic mainly due to limited testing capacities and a large proportion of undetected asymptomatic and mild infections. Iran was among the first countries with a major outbreak outside China.

Methods: We constructed a globally representative sample of 802 genomes, including 46 samples from patients inside or with a travel history to Iran.