While California officials are optimistic about the state’s continuous drop in coronavirus cases, a fourth wave of infections could stifle attempts at reopening the economy due to several factors.

4th Coronavirus Wave

University of California, San Francisco epidemiologist and infectious disease expert Dr. George Rutherford expects that about 67% of a region’s population needs to have COVID-19 immunity for herd immunity to be considered. In this situation, the transmission of the disease between humans is much more unlikely.

However, Rutherford said the number is not a set threshold, as the U.S. government’s top infectious diseases expert, Dr. Anthony Fauci, said the needed immunity was at 70% to 85%.

Experts believe across the United States, 40% of the population have immunity from the COVIF-19 virus. This is either due to vaccinations or the people who were survivors of the disease, KTLA reported.

In a campus forum last week, Rutherford said about 26% to 39% of California residents were potentially immune from the coronavirus. However, the number was much lower than the country’s average “because we haven’t had so much infection and, as a result, have not had as much naturally acquired immunity.”