While scientists have been trying to understand more about Coronavirus infection since the beginning of the pandemic, many people have been asking one question—can anyone with no symptom spread the virus? Now, after several months the Centers for Disease Control and Prevention (CDC) said that most Covid-19 cases are spread by people without any symptoms.

CDC in its newly updated guidelines noted that since people without COVID-19 symptoms are mostly responsible for the spread of the virus, the use of masks is very important. The updated guideline also noted that "CDC and others estimate that more than 50 percent of all infections are transmitted from people who are not exhibiting symptoms," and it means that at least half of the new infections come from "people likely unaware they are infectious to others".

Coronavirus Transmission

Twenty-four percent of people who transmit the SARS-CoV-2 infection to others never develop symptoms and another 35 percent were pre-symptomatic, said CDC in the guideline that was updated on Friday, November 20. According to the health agency, 41 percent infected others while experiencing symptoms.

Face Mask
CDC recommends community use of masks to prevent transmission of SARS-CoV-2. Pixabay

On the website of CDC, it was also said that the peak infectiousness comes five days after the viral infection. With such assumptions, 59 percent of the infections would be transmitted when no symptoms are developed but "could range (from) 51-70 percent if the fraction of asymptomatic infections were 24-30 percent and peak infectiousness ranged four to six days".

Infection is transmitted predominately by respiratory droplets created when people cough, sneeze, talk, or breath, and some people without symptoms are spreading the virus while being unaware of the fact that they are COVID-19 positive. But CDC said that cloth masks can help people to stop exhaling the little globs of mucus or saliva that carry the SARS-CoV-2.

Those particles can fly directly on to others, fall on surfaces to be picked up, or can linger in the air, specifically in closed room. Hence, CDC recommends "community use of masks, specifically non-valved multi-layer cloth masks, to prevent transmission of SARS-CoV-2."

As many people are planning for Thanksgiving, expecting to welcome some guests at home, CDC is asking to celebrate the occasion with people you live with. However, health officials fear that not following the CDC's recommendations could lead to seeing another spike in Coronavirus cases.