Coronavirus cases are dropping across the country—even if that drop appears to be tied to a recent official redefinition of what counts as a coronavirus “case.”

WHO recently admitted that a PCR test with a high cycle threshold is prone to generating false positives. Thus, it now recommends that those who test positive but show no symptoms not be counted as “cases.”

Regardless of whether this drop in cases is a genuinely new phenomenon or whether it has actually existed for some time and was only revealed recently because of these changes, there are definite signs of developing herd immunity against COVID-19.

For this reason, many experts are starting to be hopeful that we may have already gotten through the worst of the pandemic.

Optimism Among Scientists

Epidemiologists are becoming hopeful that 2021 won’t show another resurgent wave of COVID-19, indicating the emergence of herd immunity.

This change in the data cannot be credited to the vaccine as very few people have thus far been vaccinated. It’s estimated that 12% of Americans have received at least one dose of the vaccine but that about 25% of Americans have been infected with the virus.

In particular, cases in California have been dropping precipitously. Dr. George Rutherford, an epidemiologist at UC San Francisco, says that one of the factors fueling this development has been “naturally acquired immunity, mostly in Southern California.” He estimates that as much as 50% of Southern California residents may have already been infected with COVID-19.

“We’re really talking something starting to sound and look like herd immunity,” Rutherford said. Sounding a note of caution, however, he added that he thought “true herd immunity is a ways off in the future.”

Dr. Paul Offit, a vaccine specialist at the Children’s Hospital of Philadelphia, largely concurred with this assessment. “I could be wrong, but I don’t think we’re going to see a big fourth surge,” he said. “I think we’ve seen the worst of it.”

Some scientists have claimed that as much as 90% of the population must have antibodies to the virus in order to reach herd immunity. Emerging new variants of the virus may also slow us down on the path to achieving that goal.

“I don’t want to provide a false sense of assurance here,” said L.A. County chief science officer Dr. Paul Simon. “I think we need to continue to be vigilant.”