Defining COVID-19 Terms: Asymptomatic Transmission

June 10, 2020


Elizabeth (Izzy) Montgomery, MPA
Policy Analyst

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In this installment in our series explaining key terms and phrases used by public health officials in discussions of the COVID-19 pandemic, we look at the term “asymptomatic transmission.”

There has been substantial talk among public health officials and researchers regarding asymptomatic transmission of COVID-19. Generally, the term “asymptomatic” refers to an individual who shows no symptoms of a disease. In relation to COVID-19, an individual who is asymptomatic is infected with the new strain of coronavirus that causes COVID-19 but does not show symptoms of the disease for the duration of the infection.

It is important to distinguish between individuals who are asymptomatic and those who are pre-symptomatic. As stated above, individuals who are truly asymptomatic do not develop symptoms at any point during their period of infection. Although asymptomatic, these individuals are still capable of spreading the virus to others. In contrast, individuals who are pre-symptomatic are infected with the virus and have not yet shown symptoms, but they could develop symptoms later. Pre-symptomatic individuals may also spread the virus to others unknowingly, not realizing they are infected until symptoms develop.

Understanding and preventing asymptomatic transmission are key factors in the ongoing public health response to COVID-19. Earlier this week, an official with the World Health Organization (WHO) asserted that COVID-19 spread by asymptomatic individuals is rare. Following pushback from public health officials, the official walked back that statement, saying that scientists are still unsure as to the frequency of asymptomatic carriers passing the virus along to others.

While additional research is ongoing to fully understand the role of asymptomatic transmission, numerous studies have identified high rates of asymptomatic individuals. For example, a study assessing COVID-19’s impact on a skilled nursing facility in Washington state found that 27 out of 48 residents who tested positive were asymptomatic. At the Cummins Unit prison in Arkansas, a significant proportion of asymptomatic cases among prisoners was identified following widespread testing within the facility.

See more definitions of terms and other information about the pandemic on our COVID-19 in Arkansas page.

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