The R0 values tell us that COVID-19 is more contagious. But what factors contribute to making its spread so exponential? For this comparison, there are two main factors:
◎ Incubation Period: The time it takes from the moment you are infected to the time you show symptoms; a person is contagious during this time and for a short time thereafter.
○ The Flu: Usually about two days - you get infected and almost immediately feel sick.
○ COVID-19: Anywhere from 5 - 12 days - by the time you feel sick, you may have been going about your everyday life, spreading the virus! In some cases, people are completely asymptomatic (meaning, they never show symptoms).
◎ Herd Immunity: A form of indirect protection from infectious disease that occurs when a large percentage of a population has become immune to an infection, either through previous infections or vaccination.
○ The Flu: A percentage of the population is already immune to the seasonal flu, either because they received their annual flu shot or because they had previously been infected with the same flu strain; having a large number of people immune limits the spread of infection (example c).
○ COVID-19: A brand new disease. No vaccine and no one has developed any natural immunity; so infection spreads person-to-person without limit (example a).
The last few months have been challenging. We have watched anxiously as COVID-19 spread globally - all of us doing our parts to “flatten the curve”. But with social distancing and hygiene measures now in place, herd immunity slowly building, and collaborative research underway to develop a vaccine, scientists and medical professionals seem confidently hopeful that the spread of COVID-19 can be curtailed.