We tested two widely used nasopharyngeal test swabs used for COVID-19 PCR test sample collection by the SEM-EDS method. Scanning electron microscopic (SEM) analysis demonstrated fairly uniform artificial fibers that showed a great degree of heterogeneity in their internal composition. Elemental analysis by electron dispersion spectroscopy (EDS) revealed carbon, oxygen, nitrogen, aluminum, and silicon as main components at highly variable concentrations within the cross-sections of the fibers. In some spots, the concentrations of aluminum and silicon were as high as 7.25% and 14.06%, respectively. The base matrix appeared to be nylon with inorganic ingredients mixed in. Aluminum and silicon can both present health hazards, and this can explain the rapid-onset nasal bleed and strong and lasting adverse reactions reported by the tested individuals.
Introduction
Respiratory specimen collection techniques for the detection of SARS-CoV-2 were defined by the WHO and CDC (1,2) in March 2020, and these have become standard methods worldwide. The most widely used technique is the nasopharyngeal test swab, (3) even though a more effective and less irritating method is available (4).
The swab has a long shaft with a fiber tip made of nylon, rayon or polyester. It was reported that the specimen collection may cause a mild discomfort (3). However, numerous tested persons have reported epistaxis (4) and/or a rapid-onset irritation reaction that may even require medical attention. In one study, 28% of the swabbed individuals reported significant side-effects (5). Unfortunately, such observations are typically not followed up and often dismissed as insignificant.
However, the rapid onset of these adverse reactions suggest mechanical and/or chemical damage to the nasopharyngeal mucosa. Since the swabbing procedure is administered by trained professionals, we wanted to check out if the swabs themselves could be responsible for the observed reactions. Our test method was SEM-EDS, which allows morphological examination of the fibers and a determination of the main elements present in them. This also allows for the discovery of material heterogeneities in test samples.
Results and discussion
We tested two specimen collection swabs widely used in COVID-19 PCR diagnostic tests. Swab “K” (Figure 1A) was manufactured by Noble Bio Clinical Diagnostics Products, Republic of Korea, lot number NFS-12011-02. This is a sterile flocked nylon swab. The other sterile swab “M” (Figure 1B) provides lot number 20201130 on its packaging, but no manufacturer information is listed. This is in violation of both U.S. and European labeling requirements for diagnostic products.
Figure 1A. Swab “K” packaging
Figure 1B. Swab “M” packaging
The fiber tips of the two swabs were placed into the sample holder of a Zeiss Quant SEM-EDS system, and the fibers analyzed for morphology and elemental composition. Specifically, we were interested in finding out if the fibers have sharp surface features that could account for the reported injuries of the nasal microvasculature. Figure 2 exhibits the images of sample “M” and subsequently the EDS analysis results.
Figure 2. Fibers of sample “M”.
The endpoint of a fiber was analysed at three spots by EDS and the bulk elemental composition and concentrations were recorded. The X-ray spectra are shown in Figure 3.
.Figure 3. Elemental composition of the sample “M” swab nylon fiber.
Table 1. Elemental composition of fibers in sample “M”.
The spectra and tabulated data reveal that the fibers were not in fact made of nylon exclusively, but contained unreported bulk components of aluminum and silicon. This is in violation of prevailing regulations that require the identification of all constituents in diagnostic products. The concentrations of aluminum and silicon were variable, at some spots as high as 1.68% and 14.06%, respectively. The distribution of these inorganic components across the fibers was highly uneven, a factor that could be caused by an uncontrolled manufacturing process.
Swab “K” was tested under the same conditions and the morphology of the fibers was comparable, suggesting that both manufacturers use similar technology. However, the elemental compositions were different, with aluminum being the dominant inorganic component.
Figure 4. Fibers of sample “K”.
Figure 5. Elemental composition of the swab “K” nylon fiber.
Considering the strict manufacturing and quality procedures embodied in Current Good Manufacturing Practices, it is reasonable to suggest that this heterogeneity of the fibers is by design. Silicon is likely present as silicon dioxide (quartz) microparticles, an abrasive that can have sharp edges randomly distributed inside and on the surface of the fibers. Rotating such a fiber tip inside the nasal cavity may injure the microvasculature of the nasal mucosa, leading to the observed nose bleeds.
Table 2. Elemental composition of fibers in sample “K”.
The presence of high levels of aluminum in the fibers is another disturbing finding, particularly in sample “K” (as high as 7.25% aluminum), which is hard to rationalize. These swab fibers contain ingredients that are known health hazards to humans, but this fact is undisclosed by the manufacturers, and apparently missed by the regulatory agencies.
Aluminum is a neurotoxin and can enter the brain viathe nasal cavity. Accumulation of aluminum in the brain leads to encephalopathy-related dementia. Considering the mass (and repeated) COVID-19 PCR testing of healthy individuals, aluminum exposure of the population via swabbing could constitute a health hazard and should be discontinued. Nasal uptake of aluminum is facilitated by mucosal injury, which can be another factor involved in the reported adverse reactions. It is likely that testing more fibers at more spots could reveal even more heterogeneities in the fibers’ compositions.
There is an alternative to swabbing: The nasal rinse procedure, which is more effective in recovering respiratory pathogens and is far less intrusive to the tested individuals (6). In this study, 91% of the test subjects opted for the nasal rinse because it is easier to tolerate. Apparently, the well being of patients is of little concern for the medical industry currently; this is just one more iatrogen effect that is accepted as “normal.”
Our results revealed a disturbing pattern of noncompliance with regulatory requirements, combined with the lack of concern for the well-being of test subjects. It is ironic that the medical establishment that now strives to control human health is incapable of producing a safe and simple product in conformance with current regulatory standards.
Since the COVID-19 PCR technique is standardized, these commonly used test swabs should be reevaluated for regulatory and manufacturing compliance. We have contacted Noble Bio Clinical Diagnostics Products for further safety information on their product, but our inquires have so far gone unanswered. This is unacceptable corporate behavior, and should prompt the regulatory agencies to take action to protect patient health.
The optimal decision would be to promote nasal rinse or oral saliva sampling and discontinue the use of swabs. If viral RNA can be detected from wastewater (7), why can’t COVID-19 diagnostics tests use other sources, e.g., urine samples? These are logical questions that need an answer, and the continued proliferation of COVID-19 testing argues for improved testing protocols. Hopefully, protecting the profits of healthcare providers will not become the overarching issue here. The current atmosphere, in which essential scientific debate about COVID-related issues is discouraged, unfortunately leads to the situation we are reporting in this communication. We urge researchers to be courageous enough to scrutinize the fundamental risks and benefits of COVID-19 testing protocols, and be forthright about bringing these to light.
Acknowledgement
We are indebted to Gregory M. Vogel for his valuable comments and suggestions on the manuscript.
Competing interests
None.
References
1. World Health Organization. Laboratory testing for coronavirus disease 2019 (COVID-19) in suspected human cases: interim guidance. March 2, 2020.
2. Centers for Disease Control and Prevention. Interim guidelines for collecting, handling, and testing clinical specimens from persons for coronavirus disease 2019 (COVID-19). April 14, 2020, accessed on 08/15/2021.
3. Marty FM, Chen K, and Verrill, KA. How to obtain a nasopharyngeal swab specimen. N Engl J Med 2020; 382:e76
4. Gritzfeld JF, Roberts P, Roche L, El Batrawy S, and Gordon SB. Comparison between nasopharyngeal swab and nasal wash, using culture and PCR, in the detection of potential respiratory pathogens. BMC Res Notes 2011; 4:122-122.
5. Healthline, accessed on 08/15/2021.
6. Gupta, K, Bellino, PM and Charness, ME. Adverse effects of nasopharyngeal swabs: Three-dimensional printed versus commercial swabs. Infect Control Hosp Epidemiol. 2020 Jun 11:1.
7. Aizza Corpus MV, Buonerba A, Vigliotta G, et al. Viruses in wastewater: occurrence, abundance and detection methods. Sci Total Environ. 2020; 745:140910.