Nearly 45% of Americans have received at least one dose of Covid-19 vaccine and nearly a third are fully vaccinated, according to the Centers for Disease Control and Prevention. As the vaccination total has grown, new infection rates have fallen, with the seven-day average of new cases dropping below 50,000 this weekend for the first time since October.
But as the vaccination rate slows — it averaged 2.4 million a day over the past week, down from 3.4 million a day as of April 13 — many of those left unvaccinated either have difficulty accessing the shots or are hesitant to receive them.
Those challenges and others now have scientists and public experts saying that the United States isn’t likely to reach “herd immunity,” the point at which enough of the population is immune to the virus that its spread becomes less likely and even the unvaccinated have some protection. Apoorva Mandavilli of The New York Times reports:
“[T]here is widespread consensus among scientists and public health experts that the herd immunity threshold is not attainable — at least not in the foreseeable future, and perhaps not ever.
“Instead, they are coming to the conclusion that rather than making a long-promised exit, the virus will most likely become a manageable threat that will continue to circulate in the United States for years to come, still causing hospitalizations and deaths but in much smaller numbers. …
“If the herd immunity threshold is not attainable, what matters most is the rate of hospitalizations and deaths after pandemic restrictions are relaxed, experts believe. …
“Over the long term — a generation or two — the goal is to transition the new coronavirus to become more like its cousins that cause common colds. That would mean the first infection is early in childhood, and subsequent infections are mild because of partial protection, even if immunity wanes.”