New Studies Probe COVID Vaccine Links to Respiratory Illness and Kidney Risks — Experts Urge Caution

Two major studies published this month are raising new questions about potential health risks associated with the COVID-19 vaccine — but researchers and independent experts warn the findings should be interpreted carefully and not taken as proof of harm.

According to Fox News, one study out of Korea, published in the International Journal of Infectious Diseases, examined how patterns of infectious disease shifted during and after the pandemic and whether vaccination played a role.

Lead author Jihun Song, Ph.D., said the research showed a dramatic change in how respiratory illnesses spread.

“While influenza-like illness dropped sharply during the early pandemic, upper respiratory infections and the common cold surged in 2023 and 2024, far above expected levels,” Song told Fox News Digital. “Most strikingly, pertussis increased more than 40-fold compared to historical trends.”

The study found that people who received four or more vaccine doses were less likely to contract flu-like illnesses and whooping cough, but more likely to get common colds or other mild respiratory infections.

“We did not expect to see such divergent associations,” Song said. “These mixed associations likely reflect complex changes in immunity, behavior, and healthcare use in the post-pandemic era.”

Experts caution, however, that such results do not show causation. Dr. Jacob Glanville, CEO of Centivax, noted that the group receiving the most doses was significantly older — averaging 67 years old — which naturally increases the likelihood of hospital visits for respiratory symptoms.

“They need to do age matching and then run the analysis again,” Glanville said. “Obviously, old people go to the hospital more for colds and upper respiratory infections.”