Clinical studies show that vaccines have an efficacy rate, which means it doesn't guarantee those who get the vaccine will not get infected by COVID. Statistics demonstrate: -If two individuals are both vaccinated, with 90 percent chance they will stay safe and healthy for more than 6 months, and only with 10 percent probabilities, the vaccinated people will go to the hospital due to COVID infection. -If one individual is vaccinated and the other one is not, the vaccinated one will remain healthy with 80 percent chance and with 20 percent he or she will end up going to the hospital due to COVID infection. -And if both individuals are not vaccinated with 75 percent probabilities they will get infected, while they only have 25 percent chance of remaining safe while they are not jabbed. We know the cost of getting a vaccine (opportunity cost of going to the clinic to get the vaccine, after vaccination symptoms, opportunity cost of resting home a day after and so on) is 60 units. Needless to say, this cost is zero if the player decides not to take the vaccine option. Let's assume the benefit or the value of not infection is 100 units and the value of infection is zero.

Player 2 Vaccination (V) Not Vaccination (NV) Prob (No infection V, V) 0.9 Prob (No infection V, NV) 0.8 Vaccination (V) Prob (Infection V, V) 0. 1 Prob (Infection|V, NV) 0.2 Player 1 Prob (No infection NV,V) 0.8 Prob (No infection NV, NV) 0.25 Not Vaccination (NV) Prob (Infection NV, V) 0.2 Prob (Infection NV, NV) 0.75 Benefit Cost Net Benefit No Infection 100 Vaccination (V) Infection 0 Player 1 Benefit Cost Net Benefit No Infection 100 Not Vaccination (NV) Infection 0