Herd immunity, or as some experts now call it, “population immunity” or “community immunity” is when the majority of the population is immune to a particular disease, whether through natural infection or vaccination. When the population reaches this point, the virus has nowhere to go and the disease disappears. Then even people who do not have individual immunity are protected.
As with any disease, how many people need to be immunized to provide protection in the community depends on how contagious it is. For Covid-19, experts estimate that the magic number could be between 70 and 90% of the population immunized against the virus. The world is not close to this level.
“Given where we are today when we look at the United States and when we look at the globe, it doesn̵
That’s a good goal, Myers said, but it takes into account a number of factors in this particular pandemic that suggest the chances aren’t in its favor: vaccinating so many people would be nearly impossible; this particular virus is spreading too fast; more contagious variants threaten to make vaccines less effective; there are entire countries and pockets in the United States that have few fully vaccinated people; there are problems with access to vaccines and justice; children have not yet been vaccinated; and about a quarter of the population is hesitant or unwilling to be vaccinated.
“We know how fast this virus is spreading and how secretly. We really should have a lot of people immunized before we destroy this virus,” Myers said.
For the future, however, Dr. Bill Hanaj, an epidemiologist at the Harvard School of Public Health in Chan, said several infectious diseases have once disappeared worldwide.
“We really did eradicate smallpox once, and if it weren’t for a few extra interventions outside of vaccines, even that could still be with us,” Hanage said. “Most people who know something about an infectious disease don’t think a complete eradication is possible.”
But all is not lost. The world does not have to live in lock forever.
For example, in Israel, after about 50-55% of the population has been vaccinated, the incidence has dropped dramatically.
“We can probably get enough immunity in a population where the virus is not a major threat everywhere,” Hanaj said. Public health officials will have to keep an eye out for cases and options in the fall, but he believes people may return to some level of normal behavior anyway. “We will get there eventually and hopefully it will be through vaccination, not through infection, because the infection can kill people,” he said.
In the United States, more than 40 percent of adults are fully vaccinated, according to data released Monday by the U.S. Centers for Disease Control and Prevention. The number of new cases has dropped by 15% since last week, but the United States still averages 49,209 cases a day for the past seven days.
If the number of cases ever becomes low enough, even without the herd’s immunity, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said last Sunday, the country will begin to move toward “normalcy.”
“It’s not going to be like turning the lights on and off – we’re going from where we are right now to completely normal. It’s going to be gradual,” Fauzi told CNN’s Jim Acosta. “Little by little you will see this approach to normal.”
It is unclear how many people will need to be vaccinated to get closer to normal, Fauzi said. “I can’t tell you exactly what that number is now, because we don’t know,” he said.
If the cases are low enough, the Covid-19 becomes manageable.
“We may not get to zero. We probably won’t,” Dr. Ashish Ja, dean of Brown Medical School, told CNN’s New Day on Monday. “But if we can get infections at very low levels, most of us can get back to life in a normal way. I think we can probably live with that.”
The way to normalize is to keep testing, look for options, and vaccinate as many people as possible as soon as possible. Vaccines protect the individual and prevent the spread of variants.
“The more people get vaccinated, the fewer options. You don’t want to see this disease develop a selective advantage that makes them more contagious and then mutate in a way that would make vaccines ineffective or make the disease more severe. deadly, “said Dr. Claudia Hoyen, a specialist in infectious diseases and molecular epidemiology at University Hospitals at Cleveland Medical Center.
Hohen said the country is in a much better place than three months ago because so many of the vulnerable have been vaccinated. “But again, we have to make sure that the final game is that we try to stop this if we can,” Hohen said.
The vaccination rate is slowing down.
“Every 1% from now on will be an incredible advance for the country,” Andy Slavitt, a senior official in the White House’s coronavirus response team, told CNN last week.
That’s why the states and the Biden administration have begun to shift their focus to stimulating and encouraging people to get the vaccine.
“I think we’re going to need a lot more than this kind of effort – to get the vaccine to the people, to build trust with the communities,” said Samuel Scarpino, an assistant who runs the Emergency Epidemic Laboratory at Northeastern University.
According to him, in Israel, the vaccinators visited a bar that raised sections of people if they were vaccinated. New Jersey has just launched the Shot and Beer campaign, which offers free beer to those of age who show their completed CDC vaccination card to participating breweries.
“I was joking that you could offer tourists to break the long lobster lines in Maine in the summer if they get vaccinated,” Scarpino said.
“I think if we take that attitude and get enough vaccines for people, we could actually get to the right level to make this serious disease, which is completely disabling from a social and economic perspective, something that hasn’t been eradicated, but this is something closer to the common cold, which becomes more manageable. ”
CNN’s Ryan Prior, Jeremy Diamond, Caitlan Collins and Laura Lee contributed to this report