Risk of Infection Increases With Each mRNA COVID-19 Vaccine Dose, Study Shows

A study in Clinical Infectious Diseases found that the COVID-19 vaccine increased susceptibility to infection and was only 19 percent effective against the dominant variant when approved.

By Megan Redshaw

New research raises serious questions about the COVID-19 vaccine's long-term effectiveness and potential role in increasing susceptibility to infection.

In a recent peer-reviewed study published in Clinical Infectious Diseases, researchers found that the risk of COVID-19 increased as the number of vaccine doses increased and the vaccine became increasingly less effective against variants different from those it was designed to target.  

The study evaluated 48,210 employees at Cleveland Clinic with diverse vaccination and infection histories to determine whether the 2023-2024 formulation of the “messenger” RNA (mRNA) COVID-19 vaccine protected against COVID-19. 

(Note: Although the Centers for Disease Control and Prevention (CDC) on a recently removed webpage says that mRNA COVID-19 vaccines are “made of mRNA,” or “messenger RNA,” the U.S. Food and Drug Administration’s (FDA) product label shows COVID-19 vaccines contain artificially modified RNA—a key ingredient that is not naturally occurring and poses a substantial risk to human health. Pfizer, on its own website, confirms its COVID-19 vaccine contains modRNA.)

The 2023-2024 vaccine was designed to target the XBB lineages of the Omicron variant, but by the time it was made available to the public, most people in the U.S. were being infected by post-XBB strains. 

Of the 48,210 employees who participated in the study, 7,978 (or 17 percent) received the 2023-2024 COVID-19 vaccine formulation, and 89 percent of doses administered were Pfizer-BioNTech. 

The study showed the COVID-19 vaccine was only 42 percent effective before JN.1 became the dominant variant and only 19 percent effective after. Participants recently infected by the XBB variant or other recent variants had the lowest risk of COVID-19, as did those who received fewer vaccine doses.

According to the authors of the study, the original antigenic sin hypothesis or immune imprinting could explain why people who received more vaccine doses had an increased risk of infection. 

This hypothesis suggests that the immune system, when first exposed to a virus, develops a memory response based on that initial exposure to the antigens in the prior vaccine. If the virus later mutates, the immune system tends to rely on its "memory" of the original virus, potentially leading to a less effective immune response to the new variant. 

This concept has been observed in influenza and is being explored in the context of SARS-CoV-2, where previous exposure or vaccination might influence the effectiveness of responses to new variants. In the meantime, U.S. health agencies continue to roll out “updated” formulations of COVID-19 vaccines with little regard.  

The researchers said people with immunocompromised conditions could explain why vaccines wouldn’t appear effective; however, that would not explain the results of this study as the mean age of participants was 42 years, there were no children included, and there were few elderly participants. 

Although COVID-19 vaccines are said to work by preventing severe disease, the number of severe illnesses was so small among all participants—vaccinated or not—that researchers couldn’t examine the severity of the disease as an outcome.

Recently Approved COVID-19 Vaccines Are Already Outdated 

The study suggests that the reduced vaccine effectiveness could be due to natural immunity conferred from previous SARS-CoV-2 infection or because the COVID-19 vaccine was no longer matched to the circulating strains by the time it was approved. 

The FDA on Aug. 22 approved and authorized for emergency use new formulations of the Pfizer-BioNTech and Moderna COVID-19 vaccines for the 2024-2025 season. These vaccines are specifically designed to target the KP.2 strain of the SARS-CoV-2 virus. The KP.2 strain is part of the Omicron variant family and is closely related to the JN.1 lineage. 

Yet, as was the case with the previously approved 2023-2024 COVID-19 vaccine analyzed by researchers, vaccines targeting the KP.2 variant are already outdated, which could render the most recent version of the vaccine minimally effective. 

According to CDC data from Aug. 19, the most prevalent variant is KP.3.1.1, which surpassed KP.3 in dominance after it overtook KP.2 back in June. KP3.1.1 is currently the only major variant increasing in proportion nationally.

So, people are now lining up for their sixth or seventh dose of a vaccine developed for a variant that’s already been replaced by subsequent variants, and U.S. health agencies are ignoring the vast amount of research that shows that not only is the shot likely to be minimally effective, but may increase the risk of infection. 

Risk of Developing COVID-19 Increases With Vaccination 

A growing body of evidence, including the study in Clinical Infectious Diseases, suggests COVID-19 vaccination actually increases an individual’s risk of acquiring COVID-19. 

Another study published online in April 2022 in Clinical Infectious Diseases evaluated 39,766 Cleveland Clinic employees and found no advantage to administering more than one vaccine dose to people who previously had COVID-19. Additionally, those who received two doses of a COVID-19 vaccine were at a higher risk of infection than those who only received one dose. 

In a 2023 paper published in Open Forum Infectious Diseases, researchers evaluated the bivalent COVID-19 vaccine among 51,017 participants. They found the bivalent vaccine was only 29 percent effective against the BA 4/5 strains it was developed to target, 20 percent effective against the subsequent BQ lineages, and only 4 percent effective against the XBB lineage. Data show that the risk of COVID-19 increased with the number of vaccine doses previously received. 

A 2023 study in PLoS One compared the risk of COVID-19 among those "up-to-date" and "not up-to-date" on COVID-19 vaccination using CDC criteria. At the time, the CDC defined being "up-to-date" on vaccination as having received at least one dose of a COVID-19 bivalent vaccine.

The study found that adults considered “up-to-date” on COVID-19 vaccination when the XBB lineages became dominant did not have a reduced risk of infection than those who were not “up-to-date” on vaccination. 

According to CDC data published in December 2022, vaccine efficacy appeared lower in persons aged 50 and over who received three or four monovalent vaccine doses before receiving their bivalent booster than those who only received two doses before receiving a bivalent booster.

In a 2022 population-based cohort study published in JAMA Network, researchers aimed to estimate the proportion of persons reinfected with SARS-CoV-2 during the Omicron wave in Iceland. To their surprise, two or more vaccine doses were associated with a “slightly higher probability of reinfection compared with one dose or less.”

Finally, a preprint study published in March 2023 on medRxiv compared SARS-CoV-2 infection rates among individuals in Qatar who initially had Omicron infection but different vaccination histories. Although the data suggest two doses of a COVID-19 vaccine reduced the risk of reinfection, receiving a booster dose was associated with a higher risk of reinfection than two doses alone. 

One thing is clear: Research suggests the government's COVID-19 whack-a-mole strategy that involves repeatedly vaccinating Americans with endless outdated boosters designed to target ever-evolving variants that evade “vaccine protection” could actually be driving SARS-CoV-2 infections—in addition to subjecting people, including children, to a host of potential risks. The only entities that benefit from this type of vaccine strategy are the pharmaceutical companies.