In 10 seconds? According to a recent study falling ill with COVID-19 does not guarantee that everyone would “seroconvert” against future infections by the coronavirus. This might be due to age or the amount of viral particles in the body.
What did they discover? They have found that only 63.9% of the patients (tested 3 weeks after they’ve become symptom-free of COVID-19) had detectable level of antibodies. In other words, 36% did not develop antibodies, despite falling ill.