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[Note: If you want to read the series about COVID shot effectiveness in chronological order, please start with, “The Truth About The COVID Shots,” posted on August 11, 2025.]
This one is interesting because it was a pediatric study done by the CDC in conjunction with medical institutions in Washington, Oregon, Michigan, Arizona, and Utah. It’s called Protection from COVID-19 vaccination and prior SARS-CoV-2 infection among children aged 6 months – 4 years, United States, September 2022-April 2023. Even though the study period ended in early 2023, the paper was not published until January 2025.
First, it showed that natural immunity is effective protection from infection. “Participants with evidence of prior SARS-CoV-2 infection were less likely to be infected with SARS-CoV-2 and experience symptomatic COVID-19 compared with those who had no evidence of prior infection (HR: 0.21 [95% CI: 0.08-0.54]).” This amounts to a 79% reduction in risk of infection.
Overall, the vaccinated group had a 61% increased risk of infection compared to the unvaccinated group (HR: 1.61 [95% CI: 0.65-4.03]).
However, when looking specifically at the Pfizer vaccine combined with lack of natural immunity, that group’s performance was exceptionally poor. Pfizer-vaccinated children from the age of 6 months to 4 years without prior infection were 257% (HR 3.57, 95% CI: 1.10-11.63) more likely to develop symptomatic COVID-19 compared to the children who were unvaccinated.
This paper had 35 authors from 15 different medical institutions across the country, including the CDC and the University of Michigan. Funny, I didn’t hear about this study in the news. Did you?
A study was done using data from the Veteran Health Administration (VHA) system collected from October 2023 through May 2024, and published in March 2025. The title of the study was Effectiveness of the 2023-2024 XBB.1.5 COVID-19 Vaccines Over Long-Term Follow-up. Approximately 587,000 vaccinated veterans were compared to 587,000 unvaccinated veterans.
In the first paragraph of the Discussion section, the authors wrote, “the COVID-19 vaccine targeting the XBB.1.5 variant of Omicron was not protective against documented SARS-CoV-2 infection and had a relatively low estimated effectiveness against SARS-CoV-2-associated hospitalization (VE, 16.64%) and death (VE 26.61%).”
Indeed, the VE was -3.26% (95% CI, -6.78% to -0.22%) against documented SARS-CoV-2 infection. So, again – as demonstrated in the studies from the previous posts, the vaccinated group had a statistically significant higher infection rate than the unvaccinated control group.
This next study by Nakatani et al. was done in late 2023 in Japan and was published in 2024. It focused on employees at small and medium sized companies. It found “the odds of contacting COVID-19 were higher among vaccinated individuals compared to unvaccinated individuals (adjusted OR 1.85 (95% CI: 1.33-2.57, p<0.001).” In other words, being vaccinated increased the odds of getting infected with COVID by 85% compared to those who were unvaccinated.
When looking a little deeper and focusing on the impact of the number of COVID shots, here were the results.
“Participants who received one to two doses had an adjusted OR of 1.63 (95% CI: 1.08-2.46, p=0.020).
Those who received three to four doses had an adjusted OR of 2.04 (95% CI: 1.35-3.08, p=0.001).
Those who received five to seven doses had an adjusted OR of 2.21 (95% CI: 1.07-4.56, p=0.033).”
As people received more doses of COVID shots, their risk of infection went up significantly.