Herd immunity in U.S. may remain elusive but vaccination is key

NEW YORK - As New York City, once the epicenter of the global pandemic, shows signs of returning to normal, health officials warn COVID-19 may be here to stay. 

Early on in the pandemic, health officials suggested the U.S. could reach so-called herd immunity — meaning the virus would have nobody left to infect — if about 70% of the population developed antibodies from a COVID infection or got vaccinated against the virus. 

New, more infectious variants have made the goal of herd immunity elusive. 

Dr. Suraj Saggar, the chief of infectious diseases at Holy Name Medical Center in Teaneck, New Jersey, said herd immunity is a moving target. 

"We now have these variants out there that are much more transmissible," Saggar said. "So if something is more infectious, you need that much more of a percentage of the population to be vaccinated."

Dr. Carl Bergstrom, an evolutionary biologist at the University of Washington in Seattle, said even if COVID never disappears and we never reach herd immunity, dealing with it will become more manageable. 

"It doesn't mean we won't have pockets of herd immunity," Bergstrom said. "We should be able to get death rates and hospitalization down extremely low in this country by vaccinating the people who are at the highest risk."

Bergstrom is optimistic the U.S. is well on its way to achieving the goal of allowing us all to return to what life was like before the pandemic.