A new study by researchers associated with Stanford University Medical School shows prevalence estimates represent a range between 48,000 and 81,000 people infected in Santa Clara County by early April, 50-85-fold more than the number of confirmed cases. The population prevalence of SARS-CoV-2 antibodies in Santa Clara County implies that the infection is much more widespread than indicated by the number of confirmed cases.
Epidemiologists have known that a significant proportion of people who are infected are going undetected by the medical system because either they don’t feel sick enough to seek help or are asymptomatic. For example, recent research in Iceland suggests that about 50 percent of people infected with the virus have no symptoms.
The infection fatality rate for COVID-19, according to the Centers for Disease Control and Prevention (CDC) are just about the same as estimates for seasonal influenza.