Parents in Florida sent the University of Florida Mass Spectrometry Research and Education Center six masks to be tested for various pathogens. Results determined that they tested positive for at least 11 pathogens, some of which are common human flora and/or commonly found in soil and water. The findings were not the result of a regimented, peer-reviewed study, however, and do not support the conclusion that wearing masks could be doing more harm than good. Because there was no standardization in collecting the samples, the results did not indicate to what extent masks may collect harmful pathogens.
In June 2021, a research facility at the University of Florida tested six masks worn by children during their school day and found that at least 11 disease-causing pathogens were present on the mask material.
Following publication of the results by Florida newspaper Alachua Chronicle, a COVID-19 conspiracy theory Facebook group called PANDA promoted the findings as evidence in a June 18 post to suggest that wearing masks could be doing more harm than good, as did politically conservative websites like Town Hall and the conspiracy theory-promoting website Rational Ground.
In an email to Snopes, the University of Florida confirmed that a laboratory affiliated with the college had conducted the lab test, but that the institution did not have plans to release the report.
“The University of Florida Mass Spectrometry Research and Education Center routinely conducts lab tests for members of the public as requested, as it did for Ms. Donoho. However, it is important to note that we had no way of establishing the chain of custody for these masks and to what conditions they were exposed prior to the lab test,” a spokesperson told Snopes.
“To draw any conclusions is premature and a more controlled, peer-reviewed research is warranted. It is also important to note that Centers for Disease Control and Prevention studies indicate wearing a mask is among the most effective measures for preventing and mitigating the spread of COVID-19.”
Snopes spoke with Kari Basso, director of the Mass Spectrometry Research and Education Center at the University of Florida (MSREC), who tested the masks and shared the findings with us directly. Before we go into the details of Basso’s conclusions, it is important to note that what she found was not the result of a standardized study, nor have the findings been published in a peer-reviewed journal. Furthermore, some medical experts have expressed concern over how the study was conducted and how the results were used to question the safety and efficacy of wearing masks. The World Health Organization described the findings as a “pseudo-study.”
MRSEC is a service facility where anyone can send samples for analysis. In particular, Basso employs the use of proteomics, a study of the expression of genes that uses the structure and function of their proteins to sequence genomic data. A method known as liquid chromatography-mass spectrometry (LC-MS/MS) is used to analyze microorganisms like bacteria by extracting proteins, treating each with an enzyme to cut the protein into smaller fragments, and then measuring these fragments in such a way that the sequence is determined. Bacterial species can be detected at the strain level to identify microorganisms at all taxonomic levels, according to a 2015 study published in the journal Systematic and Applied Microbiology. LC-MS/MS is different than the traditional culturing of bacteria, which takes a sample of bacterial cells and multiplies microbial organisms to determine what types are present.
Basso instructed parents to put a fresh mask on their children. At the end of the day, they were told to put it in a zip-closed bag and place it in the freezer. A 1-centimeter square was cut from the center region of two cotton-based masks, a neck-gaiter, a T-shirt, and three surgical masks. These samples were compared against three blank masks (fresh and not worn) that were provided as a control sample. From the 1-centimeter squares, a sample was cut into smaller pieces before being placed overnight in a solution to extract the proteins.
The small-scale study did not differentiate the inside of the mask from the outside, so it is impossible to say whether the bacteria came from the skin and saliva of the child wearing the mask, or whether the mask had been contaminated through external contact. And because Basso did not directly oversee how the parents collected the mask samples, it is unclear at what point in the process they may have become contaminated. Simply put, Basso was able to determine what pathogens were present on the masks but not how they came to be there.
Below were some of the highlighted bacteria found on the masks and the conditions they can cause, according to the lab results:
| Pathogen | Description |
| Acinetobacter baumanni | Commonly found in soil and water and can cause infections in the blood, urinary tract, and lungs. Infections typically occur in people in healthcare settings and the bacteria can spread from one person to another through contact with contaminated surfaces. |
| Streptococcus pyogenes | A common bacterium that can cause strep throat, rheumatic fever, scarlet fever, and other skin infections. Streptococcal bacteria can spread through the respiratory droplets of an infected person or via shared food or drinks. |
| Porphyromonas gingivalis | This bacterium can live in the oral cavities of people and is common in individuals with poor oral hygiene or periodontal disease |
| Staphylococcus aureus | Staphylococcus bacteria is found on the skin and in the nose of healthy individuals but in some cases can cause skin infections ranging from minor boils to endocardium, a life-threatening condition of the heart. Staph bacteria are also one of the most common causes of food poisoning. |
| Neisseria meningitidis | Meningitidis bacteria are common and responsible for nearly 90% of disease caused by that bacterial species worldwide. The bacteria is found in the nose and throat of about one in 10 people without causing illness. When it invades the body, the bacteria can cause serious disease. |
| Rickettsia rickettsii | R. rickettsia is the bacterial agent responsible for Rocky Mountain spotted fever, a disease that is only spread through the bite of an infected tick. |
| Corynebacterium diphtheriae | Diphtheria is a serious infection caused by strains of this bacteria, however, most public school systems require childhood vaccination that protects against infection. |
| Legionella pneumophila | Legionella bacteria are naturally found in freshwater environments but can cause an infection when they grow and spread in human-made water systems like showerheads, hot tubs, and plumbing systems. People can contract a serious lung infection known as Legionnaires’ disease when they breathe in small droplets of water that contain the bacteria. |
Despite hyperbolized accounts of the above bacteria in media reports, a majority of the pathogens are common and rarely cause severe illness or disease. And as the study itself noted, not all bacteria are harmful or pathogenic — many of those listed in the above table are part of the human flora on skin, saliva, or in the gut, and are natural to the environment in soil and water. In several of the samples, the most abundant proteins detected are human proteins found in saliva and skin. So while the listed pathogens can be dangerous, their detected presence alone isn't enough to suggest that wearing masks may present an increased risk of exposure to deadly diseases.
Basso told Snopes that she was “shocked” by her results and that they present an opportunity for further study, but that it is not within her expertise to determine if it is factual to say that wearing masks does more harm than good. As of this writing, the Centers for Disease Control and Prevention recommends that those who are not fully vaccinated or who have a condition that may weaken their immune system should continue to wear masks in public.