"mRNA vaccines increase infectious diseases by 559% in Korean study" is false—Reading the paper correctly [Fact Check]

Claims being spread

On social media, the following claims are being spread, citing a large-scale study from South Korea:

❌ Summary of false claims

• The more mRNA vaccines you get, the more colds, upper respiratory infections, pneumonia, and tuberculosis increase

• Up to 559% increased risk

• Particularly serious in children

• "VAIDS (Vaccine-Acquired Immunodeficiency Syndrome)" has been confirmed

• A secondary article written by Nicolas Hulscher seems to be the source.
  It appears almost verbatim in "BREAKING: 51 Million-Person Study Finds COVID-19 “Vaccines” Increase Risk of Respiratory Infections by up to 559%" (Public Health Policy and Law).

Conclusion: False/Distorted

This post is a gross misinterpretation and exaggeration of the paper's content. Below, we verify this against the actual content of the original paper.

Actual content of the paper

Original paper:
Song J, Jeong S, Chun AY, Jung J, Park SJ, Park SM. Incidence of Respiratory Infections after the COVID-19 Pandemic (2023-2024) and Its Association of Vaccination Among Entire Populations in Korea. Int J Infect Dis. 2025:108194.
https://www.ijidonline.com/article/S1201-9712(25)00416-3/fulltext

<Abstract> Added in parentheses ( ).
Objective: To examine national trends in respiratory infections during and after the COVID-19 pandemic and to evaluate the risk according to the number of COVID-19 vaccine doses.

Methods: Trends were evaluated using a SARIMAX model using a database that integrated health insurance claim data and vaccination records for the entire Korean population (N=51,645,564). The association between the number of doses received by June 1, 2023, and the incidence of respiratory infections was examined using Cox hazard models and Fine-Gray models.

Results: Compared to the pre-pandemic period (2017–2019), the incidence of influenza-like illness (ILI) and pneumonia decreased by more than 90% in 2020–2021 (during the pandemic). Subsequently, in 2023–2024 (post-pandemic), upper respiratory tract infection (URI) and common cold increased again. The incidence of pertussis rose to 46 times the expected level in the latter half of 2023.

(The above represents changes over time unrelated to vaccines.)
(From here on, it relates to vaccines)

Individuals with a history of 4 or more doses (≥4th dose) compared to those who were unvaccinated or only partially vaccinated, had ILI (adjusted hazard ratio 0.55 [95% confidence interval 0.54–0.57]) and pertussis (0.06 [0.04–0.08]) risks were lower, while URI (1.32 [1.32–1.33]) and common cold (1.63 [1.62–1.64]) risks were higher.

Conclusion: With changes in respiratory infection patterns, COVID-19 vaccination in the post-pandemic period may have associations with respiratory infections that vary by disease. This reflects changes in population-level immune status and indicates the need for public health strategies that can be adaptively changed according to the situation.

What the paper actually shows

Study Overview

Subjects: Approximately 51.64 million people in South Korea (2016-2024)
Design: Retrospective cohort study
Objective:

1. Analyze changes in respiratory infections before and after COVID-19 during the following periods

Pre-pandemic (2017-2019)
During the pandemic (2020-2022)
Post-pandemic (2023-2024)

2. Evaluate the association between COVID-19 vaccination and post-pandemic respiratory infection risk

✅ Correct interpretation

1. Significant decrease in respiratory infections during the pandemic

• Due to NPIs (masks, hand washing, behavioral restrictions), influenza and pneumonia decreased by over 90%

• This led to the accumulation of "immunity debt"

2. Post-pandemic rebound

• 2023-2024 saw upper respiratory infections increase by about 2 times and pertussis by 46 times

• This is due to the resumption of social activities and the resolution of immunity debt

3. Complex association with vaccination

Risk for the group vaccinated 4 or more times
ILI (Influenza-like illness) 0.55 (45%decrease)✅
Pertussis 0.06 (94%decrease)✅
URI (Upper respiratory infection) 1.32 (32%increase)
Common cold 1.63 (63%increase )

4. The authors' cautious interpretation

• Regarding the increased risk of URI (upper respiratory infection) and common cold, multiple possible explanations are presented:

  • Differences in age composition (vaccination concentrated in the elderly)

  • Differences in healthcare-seeking behavior (people with high health awareness get vaccinated)

  • Residual confounding (factors that cannot be fully adjusted for, such as occupation and home environment)

  • Increased exposure due to the resumption of social activities

• The paper reports this as an "association" rather than "causality"

• Clearly states that the influence of confounding factors cannot be completely excluded

Why does such misinformation arise?

1. Cherry-picking data

Extracting only a portion of the paper's data (URI/common cold HR increase) and ignoring the context

2. Misinterpretation of causality

Misinterpreting 'association' as 'causality.' Even if there is a statistical association, it does not necessarily mean it is the direct cause

3. Confirmation bias

If one has a preconceived notion that 'vaccines are dangerous,' they selectively read only the information that can be interpreted that way

4. Misuse of technical terminology

Mixing in medically non-existent coined terms like 'VAIDS' to add authority

The true significance and limitations of the paper

📊 Value of the research

• Visualizing trends in respiratory infectious diseases on a nationwide scale

• Quantifying the impact of the pandemic on infectious disease ecology

• Important as foundational data for public health policy

⚠️ Limitations of the research (also clearly stated by the authors)

1. It is an observational study and cannot prove causality

2. Possibility of residual confounding (health behaviors, occupation, home environment, etc.)

3. Mild cases are not included because it is based on claims data

4. Details on vaccine type and timing are not adjusted

Perspective of medical professionals

Correct clinical interpretation

Q: Do vaccines increase the common cold?
A: It cannot be determined from this study alone. Rather:

• Elderly people and those with underlying conditions received priority vaccination

• They were a high-risk group to begin with

• Exposure increased for everyone due to the resumption of social activities after the pandemic

Confounding factors such as these should be considered.

Q: Are vaccines ineffective?
A: The opposite is true. In this study:

• Influenza-like illness decreased by 45%

• Pertussis decreased by 94%

These results demonstrate a protective effect against infectious diseases that carry a risk of severe illness.

Summary: How to read information correctly

✅ Checkpoints

1. Check the original research paper (Do not judge based solely on secondary information)

2. Read the authors' conclusions (Beware of cherry-picking)

3. Understand the limitations (No study is perfect)

4. Consider the context (Do not judge based on a single numerical value)

5. Refer to expert commentary

🚫 Warning signs

• Sensationalist expressions such as 'shocking truth' or 'was being covered up'

• Cherry-picking only the numbers

• Use of terminology not present in the paper

• Extreme interpretation

References

For those who want to know more about this paper, please refer to the following:

• Concept of immunity debt: Cohen R, et al. Pediatric Infectious Disease Group (GPIP) position paper. Infect Dis Now. 2021

• Decrease in infectious diseases during the pandemic: Brueggemann AB, et al. Lancet Digit Health. 2021

While scientific discussion is welcome, the spread of misinformation that distorts papers harms public health. Let's strive to share accurate information.

Note: Nicolas Hulscher
is an epidemiologist at the McCullough Foundation, and
its president, Peter McCullough, has been reported as someone who had his medical license revoked for spreading misinformation about COVID-19 and vaccines. (McCullough Foundation)

• The journal where Hulscher published the article, Science, Public Health Policy & the Law, is described by media bias rating sites as a
  pseudoscience site that frequently publishes vaccine misinformation and has a low rating for factual reporting. (Media Bias/Fact Check)

Evaluation of the secondary article written by Nicolas Hulscher

• Almost no consideration of confounding factors (e.g., children with high vaccination counts are often high-risk children)

• Treating only the indicators that suit one's convenience as 'real' and inconvenient indicators as 'artifacts'

• Leaping from there to very large conclusions such as 'VAIDS' and 'immune collapse'

• In addition, given that the publisher is an organization criticized for spreading vaccine misinformation, it must be evaluated as dangerous to use this interpretive article as scientific evidence.

(Translation was reviewed using ChatGPT-5.1 thinking)