3. This is not ‘flu.

As we covered earlier, viruses need to hijack human cellular machinery to replicate themselves – in the case of the influenza virus, SARS-CoV-1 and SARS-CoV-2, these cells are mainly in the throat and lungs. The symptoms tend to follow the spread of the infection: You get a fever because your immune system reacts to the infection; You cough because of the need to clear your airways and protect your lungs; the virus hijacks this to spread itself.

Although the initial symptoms of SARS-CoV-2 are “influenza-like” – it is important to distinguish it from Influenza. With ‘flu, the classical symptoms of fever, malaise, aches come on after a few days, usually at about the same time as you become infectious. Practically-speaking, this means that those infected usually self-isolate at the most important time of the infection cycle, and there is little chance of spreading the ‘flu further.

Symptoms of COVID-19

This is not the case with SARS-CoV-2. Unlike ‘flu, most of the spread SARS-CoV-2 is before the onset of symptoms. With this virus, symptoms tend to start 5-11 days (mean 5.2 days) after exposure,  which may be several days after you became infectious. This allows for this virus to be spread widely, quickly>

Think about this difference: With ‘flu, you would socially isolate at the point of being infectious, but with SARS-CoV-2 you might not – you could continue to interact with people for days at exactly the time when you are spreading the infection. This is why social isolation for this disease, even in the absence of symptoms, is so important.

From the perspective of taking x-rays, you may not think of this as an issue; most patients admitted into this part of the care pathway are often exhibiting symptoms. But what about people admitted because of an accident, or if you are simultaneously treating patients without symptoms? We will cover how the virus is transmitted, later in this document.