4.3. Chance of re-infection
The main conundrum is whether primary COVID-19 infection prevents the second infection and how long the patient is immune. Unfortunately, affliction to COVID-19 does not appeared to prevent further infection, especially for a long time. This finding most likely reduces the success of vaccine candidates. Furthermore, studies suggest that there are genetically distinct strains of the SARS-CoV2 in communities where infection with one does not confer full immunity against the others. The finding was made in a case study by Tillett et al. that the infection occurred with two genetically distinct SARS-CoV2 strains which did not appear to have occurred naturally during evolutionary mechanisms in the human host shortly [32].