One of the main questions asked during this crisis was whether asymptomatic Covid-19 were contagious. A study by the Chinese Center Disease Control and Prevention has attempted to answer this very question by studying 455 subjects exposed to asymptomatic carriers.
Subjects were divided into 3 groups:
196 family members
224 hospital staff members
The study looked at epidemiological information, clinical records, auxiliary test results and therapeutic programs. The average contact time for patients was 4 days (5 days for relatives).
Cardiovascular disease accounted for 25% of the patients’ original diseases.
In addition to hospital staff, both patients and family members were isolated.
During the quarantine, 7 patients and a family member experienced respiratory symptoms (of which fever was the most frequent) while the blood count returned to normal intervals in most subjects.
All CT images showed no signs of Covid-19 infection and no Sars-Cov-2 infection was detected for severe acute respiratory syndrome in 455 contacts when they underwent nucleic acid tests.
To summarize, the 455 contacts studied were not infected by Covid-19 and it was concluded that the contagiousness of some asymptomatic carriers of Sars-Cov-2 could be weak.
The ISS and WHO admit the possibility of transmission of the virus from infected asymptomatic subjects, but stress that this is a rarity.
If a person has no symptoms, it means that he has no fever, cold, cough and has very little chance of passing on the virus.
“Based on what is already known about coronaviruses, writes the ISS, we know that asymptomatic infection could be rare and that transmission of the virus from asymptomatic cases is very rare. Based on this data, the WHO concludes that the transmission from asymptomatic cases is probably not one of the main means of the Covid-19 transmission.”