Herd Immunity Against COVID-19 ‘May Not Be Possible’: CDC
Herd immunity against the virus that causes COVID-19 may be impossible to reach, a federal health official said in little-noticed remarks earlier this month.
“We would discourage a strict goal of a threshold where we think if we reach that, that community transmission will then cease,” Dr. Jefferson Jones, a medical officer on the Centers for Disease Control and Prevention’s (CDC) COVID-19 Epidemiology Task Force told a panel of the agency’s vaccine advisers.
“I think thinking that we will be able to achieve some kind of threshold where there’ll be no more transmission of infections may not be possible,” Jones said.
Herd immunity, or community immunity, refers to a situation where a certain percentage of a population has immunity against an infectious disease. Immunity can come from vaccination or prior illness. When the percentage is reached, the collective immunity offers some protection to people without immunity because “the disease has little opportunity to spread within the community,” according to the CDC.
Some officials had hoped that the combination of vaccine-conferred immunity and natural immunity, or protection from prior illness, would one day reach a high enough proportion of certain areas, and eventually the entire United States, to achieve herd immunity.
Dr. Anthony Fauci, for instance, said last year that an impact would be seen when as little as 50 percent immunity was reached. Blanket herd immunity, or a wider range of protection, would take up to 85 percent immunity, he said during an NPR interview.
Waning protection against infection from vaccines is driving the newer predictions that herd immunity may never be reached.
Achieving community immunity will be “very complicated with waning immunity,” Jones said during the Nov. 2 meeting. All three shots authorized in the United States decline sharply in effectiveness as time elapses, studies have shown. The number of COVID-19 cases, hospitalizations, and deaths in people who have been vaccinated has risen in recent months.
“Emerging evidence shows that vaccine effectiveness against COVID-19 infections is decreasing over time,” Dr. Rochelle Walensky, the CDC’s director, told a Senate panel during a recent hearing.
Jones was answering a question from Dr. Oliver Brooks, chief medical officer of Watts Healthcare and a member of the agency’s vaccine advisory panel. Brooks wanted to know if vaccinating 5- to 11-year-olds would help reach herd immunity; shots for that age group were recently cleared by U.S. drug regulators and the CDC.
Brooks told the Los Angeles Times that more Americans need to get a COVID-19 vaccine but that the CDC’s new message ““almost makes you less motivated to get more people vaccinated.”
About 68 percent of the U.S. population is fully vaccinated as of Nov. 15.
Dr. John Brooks, a CDC official helping lead the agency’s response to COVID-19, answered by saying 70- to 80-percent immunity is good enough for herd immunity against many other diseases but the CCP (Chinese Communist Party) virus, which causes COVID-19, “has a lot of tricks up its sleeve, and it’s repeatedly challenged us.”
“It’s impossible to predict what herd immunity will be in a new pathogen until you reach herd immunity,” he added.
Experts have been debating herd immunity since the beginning of the pandemic. Many reached the conclusion that herd immunity was practically impossible months ago. “We need to be cognizant that even with the vaccine, we probably will never reach herd immunity,” Kamran Kadkhoda, medical director of the Immunopathology Laboratory at the Cleveland Clinic, wrote in a January paper.
Professor Francois Balloux, director of the University College London’s Genetics Institute, said over the summer that the emergence of the Alpha and Delta strains of the CCP virus made it more likely that most people around the world would get infected by the virus more than once over their lifetime.
Initial vaccine trials that suggested a high efficacy against infection led to optimism but herd immunity “rapidly turned out to be impossible” because of the waning immunity and the newer, more transmissible strains, Balloux told The Epoch Times over Zoom.
“Unless we get another generation of vaccines, which are better blocking transmission, I think we won’t see anything like traditional herd immunity in the sense of measles,” he added.
The waning vaccine effectiveness triggered clearance for booster doses for tens of millions of Americans in recent months. Some of the most-vaccinated states, meanwhile, are seeing new case records lately, including Vermont.
A growing number of experts have said they think COVID-19 and the CCP virus will be a problem the world will be dealing with for years, if not permanently.
“We’re going to be dealing with this for at least another five to 10 years,” Dr. Michael Saag, professor of medicine and infectious diseases at the University of Alabama Birmingham, told The Epoch Times last month.
“The virus will never go away. It will be endemic. We’ll always have it with us. It’s always going to kill a few older people ever year, just like the annual influenza does, but we won’t have these huge waves,” Martin Kulldorff, senior scientific director at the Brownstone Institute, told The Epoch Times last month.
Balloux also sees the pandemic heading towards an endemic stage. While many people who get infected a second or third time will see few ill effects, those at higher risk of severe effects, like the elderly, should get vaccinated to protect themselves, he added.
In the United Kingdom, officials long ago shifted away from targeting herd immunity, Balloux said. The strategy is now focused on reducing people’s risk of hospitalization and death, primarily through vaccinating more people.
“I don’t think in the UK anyone still hopes actually to eliminate the virus,” he said. “You might find someone, but not many.”