According to the CDC, symptoms generally appear 2 to 14 days after exposure to the virus, although some people never exhibit symptoms. In the days leading up to symptom onset, the infected person is still contagious. The CDC estimates that 50 percent of transmissions are from pre-symptomatic people. “The possibility of pre-symptomatic transmission increases the challenges of containment measures,” the CDC states. The key to mitigating pre-symptomatic spread is to self-quarantine for two weeks if you believe you have come in contact with a COVID-19 case—even if you are not exhibiting any symptoms. The CDC says that pre-symptomatic transmissions underscore the importance of social distancing and other preventative measures.ae0fcc31ae342fd3a1346ebb1f342fcb RELATED: For more up-to-date information, sign up for our daily newsletter. A recent study published by Proceedings of the National Academy of Sciences of the United States of America (PNAS) looked at the impact of “silent transmissions” (defined as pre-symptomatic and asymptomatic spread) in controlling COVID-19 outbreaks. The study found that due to the pervasiveness of “silent transmissions,” symptom-based isolation cannot stop the spread of the coronavirus on its own. According to PNAS, quarantining those with symptoms “must be supplemented by rapid contact tracing and testing that identifies asymptomatic and pre-symptomatic cases, in order to safely lift current restrictions and minimize the risk of resurgence.” Since 50 percent of transmissions are occurring before people show symptoms of the virus, protocols must be put into place to account for this significant source of infections. And for information on asymptomatic spread, check out The Number of COVID Patients Without Symptoms Is Growing, CDC Says.
