When you are infected with a virus, the effects can range from nothing to you die. You could get infected without even getting sick, and then infect someone that is vulnerable and they die. It seems to be that most people that get the virus don't even get sick (I guess this from the numbers of cases while they are leveling off--if most people got sick, I would expect a country like Germany to see closer to 10 million cases instead of 100,000 at peak). This shows what an even somewhat healthy immune system can do to this virus.
When you get infected with the truth, you get relief from the lie. This can so easily spread because the truth actually makes sense. Once something actually makes sense, you are not going to revert to the lie except under force. Besides this, how many people became "infected" with the truth due to the lie itself? That would be as stupid as having people catching coronavirus simply due to being kept isolated from it or due only to being cut off from it. How often does that happen? Then why did we not have coronavirus cases prior to late 2019? We did, however, have the first case of the Truth long before anyone had the "infection".