Natural Immunity Better Than COVID-19 Vaccination Against Omicron: CDC Study

The U.S. Centers for Disease Control and Prevention (CDC) headquarters in Atlanta, Ga., on April 23, 2020. Tami Chappell/AFP via Getty Images

Post-infection immunity is superior to protection from COVID-19 vaccines, according to a new study from U.S. Centers for Disease Control and Prevention (CDC) researchers.

Natural immunity, or postinfection immunity, provided 76 percent protection against COVID-19-associated hospitalizations while Omicron was the dominant virus strain in the country, the researchers found. A primary series of the Moderna or Pfizer vaccine, in people without a prior infection, provided just 39 percent protection.

Natural immunity also lasted longer at higher levels than both primary series of vaccination and vaccination with a messenger RNA booster on top of a primary series, according to the study. During Omicron predominance, natural immunity against hospitalization was 74 percent 150 or more days after infection. A primary series without prior infection remained just 39 percent protective beyond 149 days, while three doses started at 81 percent protection but waned to just 31 percent after 150 or more days following the third dose.

The paper was published ahead of peer review by The Journal of Infectious Diseases. It was funded by the CDC.

“Protection from COVID-19 mRNA vaccination and/or prior SARS-CoV-2 infection against COVID-19-associated hospitalizations ... regardless of variant [was high],” Catherine Bozio of the CDC and the other researchers said. SARS-CoV-2 causes COVID-19.

The agency, which recommends a primary series and a bivalent booster for virtually all Americans 6 months of age and older, regardless of prior infection, did not respond to an email asking if the study’s findings would lead to a recommendation change.

Robert Moffit, a senior research fellow at the Heritage Foundation’s Center for Health and Welfare Policy, told The Epoch Times that the study’s acknowledgment of natural immunity “is a very significant development.”

“Natural immunity has very direct relevance for federal policy, and really, the vaccine policy, particularly the enforcement of mandates on individuals, not only in the government but also the private sector,” he said.

Researchers examined data from the CDC-run VISION Vaccine Effectiveness Network to examine patients who went to emergency room departments, urgent care facilities, or hospitals. The study period started on August 26, 2021, while Delta was still dominant, and went through June 13, 2022.

People were counted as unvaccinated if they had no record of vaccination. People who received Johnson & Johnson’s vaccine, people who only received one vaccine dose, and people who received two vaccine doses but 14 days had not elapsed before testing, were excluded. People were counted as having a prior infection if they tested positive 90 days or more before the index test date, defined as “the date of specimen collection associated with the most recent positive SARS-CoV-2 test result within the 14 days prior to” a COVID-19-associated health care visit, or the date of the visit itself if testing occurred later.

New Study Confirms Previous Research

The study comes about a year after a CDC study found natural immunity was superior to vaccination while Delta was the dominant strain.

Omicron displaced Delta in late 2021.

Other studies have also determined that vaccine-bestowed protection was not as good against Delta or Omicron as that found in people who recovered from COVID-19.

Researchers in Qatar, for instance, reported in late 2022 that natural immunity protected better against infection and severe or critical COVID-19 from Omicron than a Moderna or Pfizer primary series.

An Israeli study found as early as August 2021 that prior infection was superior to vaccination during the Delta era.

For the new paper, researchers looked at part of that time. And they found that during Delta, natural infection provided 91 percent protection against COVID-19-associated hospitalization, versus 73 percent from a primary series.

While natural immunity grew stronger over time, vaccination-bestowed immunity grew weaker, the researchers found. Against Delta, two doses dropped from 85 percent protection to 69 percent protection after 150 or more days, and three doses provided 66 percent protection beyond 149 days.

So-called hybrid immunity, or vaccination on top of natural immunity, was better than vaccination alone. Some experts support vaccinating people with infection-induced immunity but others have warned against it, noting some research has found the naturally immune are at higher risk of side effects.

Alignment With CDC Guidance

As is typical with the CDC and CDC-funded studies, the researchers included statements in support of vaccination.

“Although infection-induced immunity provides protection, SARS-CoV-2 infection can cause severe disease, death, and long-term morbidity,” they wrote.

“COVID-19 vaccination is safe and effective at preventing severe COVID-19 disease, and staying up to date continues to provide protection, regardless of history of prior infection. COVID-19 vaccination also enhances protection in persons who have been previously infected,” they added.

The researchers did not mention vaccine side effects or examine vaccine safety in their study.

“One of the more remarkable features of this entire pandemic has been the tendency of the CDC and other federal officials to either ignore scientific evidence relating to natural immunity and COVID-19 or to downplay it. And I think that has been a very serious problem,” Moffitt said.

In its investigation of COVID-19 and the vaccines, Congress should examine, Moffitt said, the pursuit of vaccine mandates and the consistent downplaying or ignorance of natural immunity.