Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2), the etiologic agent of coronavirus disease (COVID-19), has spread globally in a very short period.

This article presents a comprehensive review of the evidence on the transmission of this virus.

Strong evidence from cases and cluster reports indicates that respiratory transmission is dominant, with proximity and ventilation being pivotal determinants of transmission risk.

The virus has heterogeneous transmission dynamics: Most persons do not transmit the virus, whereas some cause many secondary cases in transmission clusters called “Superspreading events.”

The various modes of transmission are respiratory, fomite or direct, domestic pets and farm animals, vertical, fecal aerosol, sexual and bloodborne. 

Amid the COVID-19 pandemic, initial uncertainty about transmission, at times, fueled by waves of misinformation or overinterpretation of in vitro studies, understandably led to fear among both health care workers and the general public. Through the extraordinary dedication of health care workers, public health leaders, and scientists around the globe, and with rapid knowledge sharing, we have made remarkable progress in our understanding of the transmission of this virus and how to reduce its spread.

We must continue to stay up to date with the new and emerging evidence and work quickly to revise our policies to reflect this updated information.