https://thenextweb.com/syndication/2020/04/11/heres-why-well-never-know-if-a-high-viral-load-corresponds-to-a-worse-case-of-coronavirus/

Healthcare workers are likely to be in contact with many COVID-19 patients every day. Being in contact with more people with the disease means that, in theory, they will be exposed to higher doses of the coronavirus over time. Does that mean they are at greater risk of contracting the disease, as reports from some countries suggest?

We know for some diseases that the dose of virus a person is exposed to will directly correlate with how severe the disease is. A good example of this is influenza. A 2015 study from the US showed that the higher the dose of influenza virus given to healthy volunteers, the worse their symptoms. Viruses are tiny particles that must get into our cells in order to replicate, so the logic is that the more starting virus particles there are, the more cells will be infected.