(ABC4) – COVID-19 case numbers are rising in all parts of the United States. But is there a way we could determine how much of the population has been infected with the virus and achieve that all-important herd immunity?

The concept of herd immunity has been proposed as one way to address the ongoing COVID-19 pandemic.

Achieving herd immunity would mean enough of the population has developed immunity to the coronavirus after either having been infected with it or having gotten a vaccine.

When enough people are immune to the virus, it’s much harder for it to spread, and the pandemic curve will begin to fall towards zero. but experts estimate we would need 60-70 percent of the population to be immune to establish herd immunity.

One way we can determine how much of the population has had COVID-19 and therefore is immune to the virus is by checking a person’s blood for antibodies to the virus.

To do this, a team at the CDC used blood samples collected between July and September from all 50 states as well as D.C. and Puerto Rico and determined how frequently these samples carried antibodies to the novel coronavirus, which suggests prior infection and potential immunity.

The team was able to estimate the proportion of the population who’d previously had COVID-19 in 48 of the studied areas, and in 42 of them, fewer than 10% of the population had antibodies to COVID-19.

The Northeast had the highest estimate of people with evidence of prior COVID-19, but even that was only 23 percent.

Still, a long way away from the 60-70 we need to establish herd immunity, which means the vaccines will be the major key to returning to normal.

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