Herd immunity, or as some experts now call it, is “crowd” or “community” immunity, which refers to the time when most people are immune to a certain disease through natural infection or vaccination. When the population reaches this point, the virus has nowhere to go and the disease subsides. In this way, even people without personal immunity are protected.
As with any disease, how many people need to be immunized to provide community protection depends on its infectiousness. For Covid-19, experts believe that the magic number may be 70% to 90% of the population immune to the virus. The world is still far from this level.
Covid-19 director Lauren Ancel Meyers said: “Considering where we are today, when we look around the United States and the world, it seems that this will not happen in the foreseeable future.” University of Texas at Austin Modeling Alliance.
Meyers said this is a good goal, but she pointed out many factors in this pandemic, which indicate that the disadvantages are small: it is almost impossible to vaccinate so many people. This particular virus spreads too fast; more infectious variants may reduce the effectiveness of the vaccine; in the entire United States, there are few people who are fully vaccinated; there are vaccine access and fairness issues; children have not yet been vaccinated ; About a quarter of the population is hesitant or unwilling to get vaccinated.
Meyers said: “We know how fast this virus spreads and how latent it is. Before we can eliminate this virus, we really must have a lot of people immunized.”
However, from a perspective point of view, Dr. Bill Hanage, an epidemiologist at Harvard University’s Chenhe School of Public Health, said that almost no infectious disease has become extinct on a global scale.
Hannager said: “We have only really eliminated smallpox. If it is not for further interventions in addition to vaccines, even if that may still exist.” “Most people who don’t know anything about infectious diseases think that eradication is impossible. of.”
However, all is not lost. The world does not have to live in a blockade forever.
For example, in Israel, after about 50-55% of the population received the vaccination, the incidence rate dropped sharply.
Hannage said: “We may gain enough immunity in people where the virus is not a major threat everywhere.” In the fall, public health officials must pay attention to cases and mutations, but he thinks people can recover anyway. Some degree of normal behavior. He said: “We will eventually get there, hoping that this will be through vaccination rather than infection, because infection will kill people.”
According to data released by the US Centers for Disease Control and Prevention on Monday, more than 40% of adults in the United States have received full vaccination. Since last week, the number of new cases has fallen by 15%, but in the past 7 days, the United States still has an average of 49,209 cases per day.
Dr. Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases, said that if the number of cases is reduced to a low enough level, the country will begin to move towards “normal” even if there is no herd immunity.
Fauci told CNN’s Jim Acosta (Jim Acosta): “This will not be like a light switch, we will return to the current position to be completely normal. This will be a gradual process.” Normal. ”
Fauci said it is not yet clear how many people need to be vaccinated to get close to normal levels. He said: “I can’t tell you the exact number now because we don’t know.”
If the number of cases is small enough, Covid-19 becomes easier to manage.
Dr. Ashish Jha, Dean of the Brown University School of Health, told CNN’s “New Day” on Monday: “We may not reach zero. We may not reach zero.” “But if We can reduce the infection rate to a very low level, so most of us can resume our lives in a normal way. I think we can tolerate this.”
The way to return to normal is to continue testing, monitor variants, and get more people vaccinated as soon as possible. Vaccines protect individuals and prevent the spread of variants.
“The more people vaccinated, the fewer variants. You don’t want to see this disease have a selective advantage to make them more infectious and then mutate to make the vaccine ineffective or make the disease more deadly. “Said Dr. Claudia Hoyen, an infectious disease and molecular epidemiology expert at Cleveland University Hospital.
Horn said the situation in the country is much better than three months ago, because many vulnerable people have been vaccinated. Horn said: “However, we still need to make sure that the end result is that if we can, we will do our best to stop this situation.”
The vaccination rate has been declining.
Andy Slavitt, a senior official of the White House Coronavirus Response Team, told CNN last week: “From now on, every 1% of the number will represent incredible progress in the country.”
This is why the states and the Biden government began to shift their focus to motivating and encouraging people to get vaccinated.
Samuel Scarpino, an assistant professor at Northeastern University’s Emergency Epidemiology Laboratory, said: “I think we will need more of these efforts-to bring vaccines to people and build trust with the community.”
He said that in Israel, vaccinators visited a bar, and if they were vaccinated, they would pick up people’s labels. New Jersey has just launched the “Shooting and Beer” campaign, which provides free beer to people of the age who present a complete CDC vaccination card at participating breweries.
Scarpino said: “I joked that if you get vaccinated in the summer, you can offer tourists to cut off the long lobster roll line in Maine.”
“I think if we adopt this attitude and provide people with enough vaccines, we can actually reach the right level so that this serious disease has been completely debilitating from a social and economic point of view and cannot be eradicated. , But it’s more similar to the common cold, it becomes easier to control.”
CNN’s Ryan Prior, Jeremy Diamond, Kaitlan Collins and Laura Ly contributed to this report