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Essential Science: Microbial concerns with vaping products grows

This year has seen an increase in scientific studies looking at microbial contamination in vaping liquids. While the reports show variability with product types and manufacturers, the concerns are sufficient and suggest a new health standard is needed.

Vaping has an association with some cases of lung injury relating to susceptible people within the population. There are multiple reasons for this, and one of those reasons could be microbial contamination.

In considering the risks, this article does not side one way or another with the use of e-cigartete and vaping products. In terms of the relative differences, a vaporizer works in much the same way as an e-cigarette. With the vaporizer, a rechargeable battery heats a small element that in turn vaporizes the e-liquid in the device. Unlike e-cigs though, most vaporizers use a tank to hold the e-liquid rather than a cartridge. e-cigarettes have the potential to benefit some people and harm others.

Current research

Speculation that vape products may present a concern with microbial risks specifically appears in a study published in the American Journal of Respiratory and Critical Care Medicine (“Microbial Toxins in Nicotine Vaping Liquids”). e-Cigarettes come in many shapes and sizes but generally contain a battery, a heating element, and an e-liquid reservoir; yet some general conlcusions can be drawn out.

In this research piece, scientists from Harvard state that one of the potential causes for acute lung inflammation, as detected with vapers, appears related to exposure to microbial toxins. This connects with studies that show levels of microbial toxins present in many vaping liquids, as used with e-cigarette devices.

There are other factors that trigger lung disease in association with vaping products, including the effects of different chemicals. This is to the extent that the Centers for Disease Control and Prevention (CDC) has adopted a term for all conditions called “E-cigarette, or vaping, product use–associated lung injury (EVALI)”.

In terms of microbial risks, there are two main types: endotoxin and beta-glucan. The former is associated with bacteria, the second with fungi.


Bacterial endotoxin is a component of the outer cell membrane of Gram-negative bacteria (such as the types of bacteria found in water) called lipopolysaccharide (LPS). LPS is the biologically active portion and one part, called Lipid A, exerts a powerful biological response modifier which can function to stimulate the mammalian immune system, triggering fever and sometimes endotoxic shock (which is a form of sepsis).

In terms of risks, there are established concerns about exposure to bacterial endotoxins, specifically the role cellular fragments play in relation to respiratory inhalation health. This includes triggering conditions such as asthma. We know that endotoxin in outdoor air, as linked to certain pollutants, is significantly associated with an increased risk of asthma exacerbation in children.

In another study, published in Environmental Health Perspectives, researchers took 37 cartridges and 38 e-liquid products. The analysis showed that endotoxin and glucan were present. Endotoxin concentrations were over the limit of detection in 17 of 75 products tested (or 23 percent).

More research is required to help to identify sources and routes of contamination, and evaluate health effects associated with the use of contaminated products.

More concerningly, the same study found that glucan concentrations were greater than the limit of detection in 61 of 75 products (or 81 percent).


Glucans are the most abundant polysaccharides in the cell walls of fungi, and their structures are highly variable. The exact relationship between glucans and human health is complex. This could extend to immune system suppression as well as respiratory problems including asthma and infections.

Sources of contamination

With the origins of the microbial toxins are, there are different potential sources. These, as I’ve written elsewhere, include the cotton wicks in cartridges, tobacco leaves as the origin of natural nicotine, storage containers for the e-liquids, and the raw materials for producing synthetic nicotine and flavoring chemicals.

In addition to the sources, weak controls around manufacturing conditions could compound the problem. Consequently, contamination of the products can potentially occur at any point during the production of the ingredients or of the finished e-cigarette product.

Essential Science

This article forms part of Digital Journal’s long-running Essential Science series, where new research relating to wider science stories of interest are presented on a weekly basis.

Last week the topic was the development of coronavirus vaccines and mutations, both of these the issues have hit the news agenda. With mutations this included stories about minks and cross-infection to humans, and a predominant mutation within the US and Europe. In terms of good news, the presence of the mutation may help to develop an effective vaccine.

The week before the focus was with several new reports concerning obesity and ill-health effects. Included within these reports are on-going concerns about obese people and a greater chance of developing more severe COVID-19 symptoms.

Tim Sandle/Digital Journal