Читать книгу Viruses: More Friends Than Foes (Revised Edition) - Karin Moelling - Страница 15

A surprising property of CoV-2 is the fast transmission and infection rate. People can be virus carriers before they fall ill and while they still show no symptoms. They do not know that they may be infectious; in fact they are most highly infectious for two or three days before symptoms of the disease occurs. This danger, too, can be reduced by wearing a mask.

Infectiousness before disease symptoms appear differs between coronavirus disease and Influenza; in the latter, high fever occurs at the beginning of the illness. CoV-2 is thought to be unique in this respect — but this is not true. The children’s disease chickenpox is similarly contagious (its German nickname is “wind-pox”, as fast as the wind). Its medical name is Varicella zoster, and it is a herpes virus that most children no longer get, thanks to vaccination. However, the disease can be reactivated and return in the elderly as Herpes zoster. Worldwide, about 140 million cases of chickenpox and Herpes zoster occur every year. Transmission of SARS-CoV-2 resembles that of chickenpox virus!

The viral load of the new coronavirus CoV-2 is highest 2 to 3 days before the onset of manifest disease and then continues to be high for about 4 days before it declines. Low amounts of virus persist for longer, 2 or 3 more weeks, though most probably without high infectiousness.

The incubation period (the time between infection and beginning of the disease) is about 5 to 7 days, sometimes 2 to 14 days. For safety reasons the time in quarantine (the maximum time between encountering an infectious person and the beginning of the disease) is 14 days. The quarantine period is set to be so long and strict so that nobody who is infected escapes detection. Could it be made shorter? The German authorities have published two quarantine periods, 8 days for health-care workers (they are described as “relevant” for keeping the health “system” up and running) and two weeks for other people. Surprising.

Daily news bulletins are reporting about the statistics of the disease. At the beginning of May 2020, the worldwide registered number of cases was close to 3 million, and the death toll was close to 200,000 cases.