Why some people get very sick with COVID-19, some not at all

There are so many mysteries still to be determined about COVID-19 – how much antibody is enough to ward off infection, why long COVID-19 happens and in whom, does loading dose matter in terms of getting infected, what is the rate and risk of re-infection, does asymptomatic infection offer as much long-term protection as a severe case, and on and on and on – but certainly one the most important is why do some people get so sick with COVID-19 while others walk away with only an asymptomatic infection.

So the good news is that a new study from British researchers has come up with what seems like at least a partial explanation.

What this research determined from the UK experience is, unsurprisingly, that people with asymptomatic cases tended to mount a stronger antibody response (at least for certain types of antibodies) than did people with more severe disease.

Does this mean, then, that people with asymptomatic infections – given that they produced more antibodies – will have better protection against re-infection perhaps than people with more severe illnesses?

Not at all.

The ability to fight off re-infection is not simply governed by the immediate response of antibodies – both amount and type – to that virus but is determined by several other aspects of immunity as well.

Another small step for good science.