New US research adds fresh evidence that forever chemicals may impair the body’s ability to fight infections, with stronger effects in vulnerable groups.
A growing body of evidence suggests that exposure to PFAS – widely known as “forever chemicals” – may weaken the immune system in adults, according to new research from Michigan State University.
The findings deepen concerns about the long-term health implications of these persistent environmental contaminants, particularly as regulatory efforts continue to evolve.
Persistent chemicals with long-term effects
PFAS – short for per- and polyfluoroalkyl substances – are a large group of synthetic chemicals used in a wide range of industrial and consumer products, including nonstick cookware, water-repellent textiles and firefighting foams.
They are often referred to as forever chemicals because they resist degradation in both the environment and the human body. Some compounds can remain in the bloodstream for years.
One chemical highlighted in the study, perfluorohexanesulfonic acid (PFHxS), can persist in the body for nearly a decade. Its longevity makes it a useful indicator of long-term exposure and raises particular concern among researchers studying cumulative health risks.
Study finds reduced antibody response
The research focused on individuals previously exposed to PFAS through contaminated drinking water.
Scientists observed that participants with higher concentrations of these chemicals in their blood produced fewer antibodies when confronted with a new viral infection.
Antibodies are central to the body’s immune defence, identifying and neutralising harmful pathogens. A reduced antibody response suggests the immune system may be less able to mount an effective defence against infections.
The study offers a clearer picture than earlier research, which often produced inconsistent results due to difficulties isolating PFAS exposure from prior immune responses. By examining how the body reacts to a novel virus, researchers were able to assess immune function more directly.
Stronger effects in certain populations
The analysis found that the impact of PFAS on immune response was not uniform across all groups.
The reduction in antibody production was most pronounced among older adults, men and individuals with higher body weight.
These groups are also more likely to carry elevated levels of PFAS, suggesting a compounding effect where both exposure and susceptibility intersect.
While the study focused on adults, previous research has already established links between PFAS exposure and impaired immune function in children. The new findings extend those concerns across the lifespan.
Real-world exposure and public health implications
Communities affected by contaminated water supplies have been central to understanding PFAS-related health risks. In areas where industrial pollution has entered drinking water systems, residents often experience prolonged exposure without immediate awareness.
Such cases have brought attention to potential downstream effects, including reduced vaccine effectiveness and increased vulnerability to infectious diseases.
Researchers note that while PFAS exposure is widespread, it is not inevitable. Drinking water remains one of the most significant pathways, making it a critical target for intervention.
Regulatory landscape still evolving
The findings arrive amid ongoing policy debates in the United States over how to regulate PFAS in drinking water.
Federal authorities introduced the first enforceable limits on certain PFAS compounds in 2024, though timelines and enforcement mechanisms continue to shift.
Scientists argue that the latest evidence strengthens the case for stricter controls and sustained monitoring. Reducing PFAS levels in water supplies is considered one of the most effective strategies for lowering population-wide exposure.
A continuing area of research
Despite increasing clarity, questions remain about the full scope of PFAS-related health effects.
Researchers emphasise the need for long-term studies to understand better how chronic exposure interacts with ageing, metabolic factors, and immune resilience.
What is becoming clearer, however, is that these chemicals may have broader biological consequences than previously understood, including the potential to weaken the immune system in adults.