The Delayed Curve

The Epidemiological curve, or “epi-curve,” wasn’t designed to satisfy the public’s desire for instant understanding about the spread of COVID-19. Infections confirmed today were contracted days or even weeks earlier. (It takes time for symptoms to present, medical help to be obtained, tests to be taken and results confirmed.) In this visual, VPAP shows how information Virginia gathered during the week ending April 5 revealed the spread of COVID-19 in early March.

The epi-curve

For up-to-date information about the spread of COVID-19 in Virginia, please refer to

What COVID-19 Antibody Tests Can and Cannot Tell Us

Antibody tests could help scientists understand the extent of COVID-19’s spread in populations. Because of limitations in testing accuracy and a plethora of unknowns about immunity itself, however, they are less informative about an individual’s past exposure or protection against future infection.

Five Things to Remember When Interpreting Epidemiologic Data

We know that the number of cases we have on record is an underrepresentation of the true burden for several reasons. Some underrepresentation is because testing for SARS-CoV-2 might not be available for the infected person… Another factor is that not everyone will need to see a doctor for COVID-19. The World Health Organization (WHO) published a very detailed report about the outbreak of COVID-19 in China and found that 80% of cases were mild or moderate. Since then, there have been studies that have identified infections in people who never develop symptoms. If someone gets infected and recovers on their own, then public health may never find out about the case.