COVID-19 is spread by close person-to-person contact and over long distances through respiratory droplets from speaking, coughing or sneezing. Symptoms may appear 2 to 14 days after exposure to the virus that causes COVID-19. A person does not need to have symptoms to spread the virus. COVID-19 can only be diagnosed with a laboratory test. An antibody test can show if you were previously infected and if your body has created antibodies in an attempt to defend itself from COVID-19.