New, preliminary research suggests that people who have a SARS-CoV-2 infection are more likely to pass the virus on during the first week after contracting it.
The CDC recommend that people wear cloth face masks in public places where it is difficult to maintain physical distancing. This will help slow the spread of the virus from people who do not know that they have contracted it, including those who are asymptomatic. People should wear cloth face masks while continuing to practice physical distancing. Instructions for making masks at home are available here. Note: It is critical that surgical masks and N95 respirators are reserved for healthcare workers.
All data and statistics are based on publicly available data at the time of publication. Some information may be out of date.
Since January, when the World Health Organization (WHO) declared the new coronavirus outbreak a global public health emergency, international experts have kept on researching the virus.
The main goal is to learn enough about SARS-CoV-2 to allow specialists to develop the most effective preventive and containment strategies.
While many unknowns remain, research about the new coronavirus has been progressing fast.
One of the most recent studies — conducted by researchers from the Bundeswehr Institute of Microbiology in Munich, the Klinikum München-Schwabing, Charité Universitätsmedizin Berlin, and University Hospital LMU Munich, all in Germany — claims to have found out when the virus is at its most infectious.
The new study has not yet been published in a peer-reviewed journal, meaning that external specialists have not yet examined it for quality and accuracy.
However, its authors have made a preprint of the research paper available online. The paper’s first author is Roman Wölfel, Ph.D., from the Bundeswehr Institute of Microbiology.
To find out how likely the virus was to spread at different stages of an infection, and through what mediums, the researchers analyzed various samples that they collected from nine individuals who had contracted SARS-CoV-2.
These were all people who had attended a hospital in Munich for diagnostics and treatment, and they all experienced mild symptoms. All of these individuals were young to middle-aged adults who had no significant underlying health conditions.
The researchers analyzed samples of saliva and mucus, as well as blood, urine, and stool samples collected at various stages of the infection. They tested each of them to see if the virus was present, and if it had the ability to infect further.
Samples from the patients’ throats revealed that the virus was most infectious during the first week after the person had contracted it. This was the case with 16.66% of throat swabs and 83.33% sputum (saliva and mucus) samples.
The researchers were unable to isolate the virus in samples that they collected after the 8th day from a person’s exposure to the virus.
While blood and urine samples did not present any virus traces, stool samples did yield viral RNA.
However, the researchers were unable to create a viral culture from the virus RNA present in stool, which suggests that this may be an unlikely source of infection.
“The prolonged viral shedding in sputum is relevant not only for hospital infection control but also for discharge management,” the researchers write.
Based on their findings, they suggest that going forward, medical professionals may be able to avoid hospital bed shortages by discharging people from the hospital early on and advising self-isolation.
They note that:
“In a situation characterized by limited capacity of hospital beds in infectious diseases wards, there is pressure for early discharge following treatment. Based on the present findings, early discharge with ensuing home isolation could be chosen for patients who are beyond day 10 of symptoms […]”