Can Coronavirus Be Spread By Asymptomatic or Presymptomatic Carriers?

Can presymptomatic or asymptomatic individuals spread the novel Coronavirus – and what does that mean?

Undetectable Transmission?

The Centers for Disease Control and Prevention (CDC) released a new review, that includes evidence to back up the claim that presymptomatic and asymptomatic carriers can indeed spread COVID-19, providing more backup for the social distancing measures.

The CDC has been reviewing reports regarding presymptomatic and asymptomatic transmission, published in PubMed from Jan. 1st to April 2nd, discovering that some infected persons “may not exhibit signs or symptoms of illness,” adding that the SARS-CoV-2 RNA can be detected before symptoms appear, or that symptoms might never manifest, despite the person being infected by the virus.

The reports mainly focus on China, Germany and Singapore, with possible presymptomatic or asymptomatic transmission in the European country occurring before the community spread of the virus began, with Singapore’s cases further backing the possibility. China’s reports have certain issues, such as the inability of ruling out alternative exposure to the novel virus.

The CDC’s analysis of epidemiologic, virologic and modeling evidence showed that despite limitations, SARS-CoV-2 can indeed be transmitted by such carriers, which could mean another wave of the pandemic, or even more unconfirmed cases.

The evidence also suggests that the case-fatality rate could actually be lower than current estimates if you include asymptomatic infections, albeit with the possibility of such transmission, it only “reinforces the value of community interventions to slow the transmission of COVID-19.”

The agency also presented three questions in relation to the transmission that need further investigation – one being determining the incidence of asymptomatic compared to symptomatic infection, as well as quantifying “public health interventions aimed at reducing their infectiousness,” and finally – determining the level of SARS-CoV-2 immunity among the asymptomatic infected.