A new Danish study has found that perfluoroalkyl substances (PFAS), which people may have acquired from waterproofing materials, firefighting foam and pizza boxes, are associated with worse outcomes of COVID-19.
The pandemic has brought the world to its knees. Everywhere, hospitals are flooded with people with COVID-19, and while some barely notice that they have it, some people get really sick.
A new Danish research project shows that people’s blood concentrations of PFAS, which comes from waterproofing materials, firefighting foam and pizza boxes, increase the risk that COVID-19 appears not as a mild flu but definitely becomes dangerous.
The research has been published in PLOS ONE
“We found that the more of a specific PFAS you have in your blood, the greater your risk of having a more severe illness trajectory of COVID-19. This is especially important because both the European Union and Denmark are currently launching initiatives to reduce the concentrations of PFAS contaminants in the environment below the tight limit values set by the European Food Safety Authority and others,” says the first author, Philippe Grandjean, a physician and Professor of Environmental Medicine, University of Southern Denmark, Odense.
PFAS can harm the immune response
Philippe Grandjean has focused on how PFAS affects the human body for many years.
PFAS are fluorinated substances in which fluoride is bound to a carbon compound. They have very useful properties, including repelling water, oil and grease, which is why they are used to coat nonstick pans, carpets, rainwear and shoes.
The problem with PFAS, however, is that they are extremely persistent and do not degrade easily in the environment. This means that we all have measurable concentrations of PFAS in our bodies, depending on our exposure.
Philippe Grandjean’s previous research has shown that elevated exposure to PFAS can affect the immune system.
For example, one such study showed that PFAS in the blood can reduce the effectiveness of vaccinating children against tetanus and diphtheria. Children with a high concentration of PFAS in their blood when vaccinated developed far fewer of the protective antibodies, and sometimes the vaccine did not seem to work at all.
“Since we have found that PFAS can adversely affect the immune system, investigating whether they could also affect the severity of COVID-19 was very relevant,” explains Philippe Grandjean.
Measuring PFAS in the blood of 323 people with COVID-19
Philippe Grandjean obtained the necessary permits to link the analysed blood samples with the outcome of COVID-19 among 323 people in Denmark.
The blood samples from people with COVID-19 were obtained from the Danish National Biobank at Statens Serum Institut, and Philippe Grandjean’s laboratory at the University of Southern Denmark analysed the blood to determine the concentration of various PFAS and then linked this with how ill people became.
The illness trajectories were obtained from the Danish National Patient Registry, and the strict rules for processing personally sensitive information in Denmark meant that the results from the blood samples were linked to the data on illness on a secure computer.
The researchers thereby obtained data averages without being able to identify the various people and how COVID-19 affected them individually.
PFAS in the lungs associated with a more severe trajectory of COVID-19
In the study, 215 of the 323 people investigated had been hospitalized with COVID-19, and of these, 53 ended up in intensive care or died.
The results show very clearly that higher concentrations of a specific PFAS in the blood were associated with an increased risk of a more severe trajectory of COVID-19.
Specifically, people with measurable levels of perfluorobutanoic acid (PFBA) in the blood had a 2.19 times higher risk of intensive care or death than people without measurable levels. After the data were adjusted for age, sex and other factors, the risk was still 1.77 times higher. For blood samples taken close to the time of diagnosis, the risk was greater.
However, Philippe Grandjean was surprised because he had expected that perfluorooctanoate (PFOA), with its longer carbon chain, would be especially associated with a severe illness trajectory. However, PFBA, a short-chain PFAS, was the substance most strongly associated with the risk of a severe trajectory of COVID-19.
Nevertheless, PFBA fit with other pieces of the puzzle regarding immunotoxicity and COVID-19.
“In contrast to the other PFAS, PFBA accumulates especially in the lung tissue, and this makes good sense because respiratory illness is a serious manifestation of COVID-19. In addition, studies conducted in both the United Kingdom and the United States have shown that air pollution can increase the risk of a severe illness trajectory in COVID-19. This indicates that exposing the lungs to such toxic substances may disable the immune system so that it cannot cope with COVID-19 to the same degree,” explains Philippe Grandjean.
PFAS should be removed from the environment and people’s bodies
According to Philippe Grandjean, these results improve the insight into why COVID-19 affects some people more severely than others. He thinks that the results should have a long-term effect on what we do about the quantity of PFAS that is still emitted into the environment or disseminated via consumer products and how quickly we act.
PFAS were previously used in Denmark in food-wrapping paper and many other food-related uses; this is banned today in Denmark but not in other parts of the world. Although PFAS are used in many other products, the European Union is planning to phase them out completely. This is emphasized by the fact that the European Union’s most recent environmental exposure limit value is less than 3% of the previous one.
However, both Denmark and the other countries in the European Union often exceed the limit value.
“Since we can see how strongly any exposure to PFAS can affect our health, let’s do something about this. This is the practical implication of this study. It clearly shows that PFAS are harmful and that they can aggravate the illness trajectory from infections, including COVID-19,” says Philippe Grandjean.