The world will be close to the herd immunity threshold

New models suggest that some parts of the world could experience the benefits of herd immunity sooner than previously thought. In Mumbai, studies have found that herd immunity is already beginning to show up. And in the U.S. In a study from the Tata Institute for Fundamental Research, researchers estimated that 75% of people living in slum pockets of Mumbai and 50% of people in non-slum pockets will have Covid-19 antibodies.^[1] This study, coupled with recent findings that the herd immunity threshold for Covid-19 could be as low as 43%, means Mumbai could reach herd immunity by January.^[2] If Mumbai—one of the largest cities in the world with a population of over 19 million people—can reach the herd immunity threshold, it shouldn't be long before the rest of the world follows. In the U.S., on the other hand, a model by statistician and Emergency Risk Manager Dave Ingram suggests that if the New Infection Rate (NIR)—the most recent day’s new cases divided by the sum of the prior 14 days’ new cases—can hover around 8%, the U.S. can benefit from herd immunity at a much lower level than previously thought and by early next year. He adds that safety precautions must continue to happen regardless of the herd immunity threshold in order for his models to come to fruition, but that if the NIR can remain at 8%, herd immunity could be reached with 27% of the population being infected.^[3] Herd immunity is an incredibly scary subject that requires a significant portion of the population to get sick, and possibly die. But the benefits, which could be coming soon, will benefit us all.