It has been suggested that those with coronavirus are most infectious at the point when they first begin to develop symptoms.
The US and Germany have launched preliminary studies into this. It is thought that people with mild symptoms can be infectious for up to nine days.
The World Health Organisation (WHO) believes that this has contributed to the difficulty in controlling the spread of coronavirus, but it can be contained through social distancing measures and testing.
Coronavirus is more present early on
Maria van Kerhove, a WHO epidemiologist, explained how people have more of the virus in their body when they first develop symptoms.
During a live session on social media, van Kerhove said, “It appears from very limited information we have right now that people have more virus in their body at or around the time that they develop symptoms, so very early on.
“It can be a lot longer for people who are more severely ill”
During the session, van Kerhove was also asked about how some people with coronavirus may not develop symptoms, but if they can then still infect others.
She said, “Some estimates of around 40 percent of transmission may be due to asymptomatic [cases], but those are from models.
“So I didn’t include that in my answer yesterday but wanted to make sure that I made that clear.”
‘You might feel well, but your viral load is high’
WHO’s top emergencies expert, Dr Mike Ryan, explained that, unlike other viruses such as SARS or MERS (which are primarily found within the lower tract), coronavirus travels in the upper respiratory tract. This allows the virus to transmit droplets.
Dr Ryan said, “Now as we look at Covid-19, we have an infectious pathogen that is present in the upper airway for which the viral loads are peaking at the time you are just beginning to get sick.
“That means you could be in the restaurant feeling perfectly well and start to get a fever, you are feeling ok, you didn’t think to stay home, but that’s the moment at which your viral load could be actually quite high.
“And it’s because the disease can spread at that moment that the disease is so contagious, that’s why it spread around the world in such an uncontained way, is because it’s hard to stop this virus.”