While no one wants to consider themselves a Covid-19 super broadcaster, a new study has supported the idea that “silent transmission” – the spread of the virus by someone with no obvious symptoms – could be responsible for half of all new cases of coronavirus in the United States.
More than a third of silent infections should be identified and isolated to suppress a future epidemic, the study found.
According to data from Johns Hopkins University on Tuesday morning, 31 states are reporting higher rates of new Covid-19 cases this week compared to last week. According to the data, 15 other states are holding their ground and only four are trending downward.
“We are still on our knees in the first wave of this situation,” Dr Anthony Fauci, a member of the White House Coronavirus task force, said on Monday during a live event on Facebook / Twitter.
“And I would say it wouldn’t be considered a wave. It was a surge, or a resurgence of infections superimposed on a baseline … that never really got where we wanted to go,” said Fauci. “So this is a serious situation which we must tackle immediately.”
Asymptomatic or presymptomatic spread
Alison Galvani, director of the Center for Infectious Disease Modeling and Analysis at Yale University, and her colleagues have used models of coronavirus transmission to determine the extent to which silent transmission contributes to the spread of Covid-19.
They based the study on existing research, which indicates that asymptomatic infections account for 17.9% to 30.8% of all infections.
Assuming that 17.9% of cases are asymptomatic, the team found that presymptomatic people represent 48% of transmission and asymptomatic people represent 3.4% of transmission.
If 30.8% of the cases are asymptomatic, they found that the presymptomatic people would be responsible for 47% of the transmitted cases and the asymptomatic people would represent respectively 6.6% of the transmission.
The model assumes that Covid-19 may be most contagious at the presymptomatic stage, which is rare for respiratory infection. The team found that even the immediate isolation of all symptomatic cases would not be enough to control the spread.
To suppress a future outbreak below 1% of the population, the study revealed that it would be necessary to identify and isolate more than a third of the silent transmitters, in addition to all symptomatic cases.
Researchers stressed the need to both test and find contacts to safely lift the current social distance and restrictions on staying at home.
What you can do
Even with a mask, stay away from large crowds and 6 feet from anyone who is not in your “bubble”. If you don’t socialize, try to limit it to outdoor locations with excellent circulation and air filtration. Keep your hands away from your face.
And take a lesson from the typhoid Marie mistakes: wash your hands with soap and water frequently, for at least 20 seconds. And if some public health officials tell you that you need to take precautions, don’t ignore them. Although Mary died alone after 26 years of forced quarantine, there is still time for you to protect yourself, your loved ones and the strangers around you.