Total isolation isn’t the only way to reduce #coronavirus spread. Reducing unnecessary contacts (only invite the best people to your birthday party) helps. Based on school maths: if you roll a die 10 times, the probability of 1 or more 6s is 84%. If you roll it twice, it’s 31%.
This also applies if you reduce the nature of your contacts. For example, if you stop licking your friend’s face, maybe you go from a 6-sided die to a 20-sided die. Then the probability of at least 1 20 at your 2-mate birthday party goes down to 10%.
Even partial reduction goes a long way to reducing transmission below a critical threshold. R0 = prob of transmission on contact * infectious duration * contact rate. If we have R0 = 2 = 0.04*5*10, then halving the contact rate gets us to 0.04*5*5 = 1.
You can get there by reducing the probability of transmission (face licking intensity) too: 0.02*5*10 = 1.
