The world is in the midst of the deadly Covid-19 pandemic . An increment in the numbers of daily cases around the world is terrifying. The researchers are working hard and round the clock to find a vaccine to this deadly virus. A number of vaccines are going through different phases. But how much efficient should a vaccine be to stop the pandemic? Let us learn about the minimum efficiency required and the various vaccines in making. Will a vaccine alone be enough to stop the pandemic? It depends on the efficiency of a vaccine. A vaccine with a higher efficiency rate might be able to stop this pandemic whereas a vaccine with low efficiency rate might not be enough to stop this pandemic alone. What Does the Computer Simulations Show? The computer simulations introduces the Covid-19 virus with the virtual population with different ways and can show scenarios spreading it from person to person. The results of the simulation indicates how vaccines with different efficiency rate would affe