WO2021237293A1

WO2021237293A1 - Swab

Info

Publication number: WO2021237293A1
Application number: PCT/AU2021/050508
Authority: WO
Inventors: Eric H. Bert; Simon R. Logsdail
Original assignee: 3DMEDiTech Pty Ltd
Priority date: 2020-05-27
Filing date: 2021-05-27
Publication date: 2021-12-02

Abstract

Embodiments generally relate to a swab and a kit comprising the swab. The swab may be used to collect a fluid sample from a patient for testing. For example, the swab may comprise a nasopharyngeal swab, which may be used to test a patient for the presence of the COVID-19 virus. The swab comprises a handle, a head, and a neck extending between and connecting the head and the handle, the head comprising a plurality of spines protruding radially away from a central hub of the head relative to a longitudinal axis of the swab. The swab may be fabricated using additive manufacturing or 3D printing, for example.

Description

"Swab"

Technical Field

[0001] Embodiments generally relate to a swab and a kit comprising the swab. The swab may be used to collect a fluid sample from a patient for testing. For example, the swab may comprise a nasopharyngeal swab, which may be used to test a patient for the presence of the COVID-19 virus.

Background

[0002] Swabs are often used for collecting fluid samples from patients, such as saliva or mucus. There has recently been a high demand for nasopharyngeal swabs due to the scale of testing required during the COVID-19 pandemic.

[0003] Some swabs have been developed using 3D printing to meet this growing demand. However, there is room for improvement in efficacy, ease of use and patient comfort.

[0004] It is desired to address or ameliorate one or more shortcomings or disadvantages associated with existing swabs or to at least provide a useful alternative.

[0005] Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

[0006] Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each of the appended claims. Summary

[0007] Some embodiments relate to a swab comprising a handle, a head, and a neck extending between and connecting the head and the handle, the head comprising a plurality of spines protruding radially away from a central hub of the head relative to a longitudinal axis of the swab.

[0008] In some embodiments, the spines are substantially cylindrical with a rounded tip.

[0009] In some embodiments, the spines are arranged in a series of similar rows, each row of spines extending circumferentially around the hub with a similar angle of separation between the spines of each pair of adjacent spines in the row.

[0010] In some embodiments, each row is angularly offset about the longitudinal axis from the next adjacent row along the longitudinal axis.

[0011] In some embodiments, the offset angle between adjacent rows is substantially equal to half of the angle of separation between spines within a row.

[0012] In some embodiments, the number of spines per length along the longitudinal axis is in the range of 4 to 10 spines per millimetre.

[0013] In some embodiments, the number of spines per area relative to the surface area of an imaginary cylindrical surface defining the radial extent of the spines is in the range of 0.5 to 2.5 spines per square millimetre.

[0014] In some embodiments, the head further comprises a rounded distal tip devoid of spines.

[0015] In some embodiments, a maximum diameter of the distal tip is less than a maximum tip-to-tip span of the spines. [0016] In some embodiments, the swab further comprises a tapered portion connecting the head to the neck, wherein a maximum diameter of the tapered portion is less than a maximum tip-to-tip span of the spines, and the tapered portion tapers down to match the diameter of the neck.

[0017] In some embodiments, the swab further comprises a break-off portion connecting and extending between the handle and the neck, the break-off portion being connected to the handle by a breakpoint portion

[0018] In some embodiments, the breakpoint portion has a larger diameter than a diameter of the neck.

[0019] In some embodiments, transitions between the breakpoint portion, the handle, and the break-off portion are radiused.

[0020] In some embodiments, the swab is formed of a material comprising nylon.

[0021] In some embodiments, the material comprises nylon 12.

[0022] In some embodiments, the swab is formed as a single contiguous piece of material.

[0023] In some embodiments, the swab is formed by selective laser sintering.

[0024] Some embodiments relate to a test kit comprising a swab according to any one of the embodiments described herein.

[0025] In some embodiments, the test kit further comprises a vial containing a transport medium and configured to receive and enclose part of the swab.

[0026] In some embodiments, a length of the vial is similar to a total length of the swab head, neck and break-off portion when separated from the handle. Brief Description of Drawings

[0027] Embodiments will now be described for exemplary purposes only with reference to the drawings, in which:

[0028] Figure 1A is a side view of a swab according to some embodiments;

[0029] Figure IB is a close-up side view of a head of the swab of Figure 1 A;

[0030] Figures 1C and ID are different close-up perspective views of the head of the swab of Figure 1A;

[0031] Figure IE is a distal end view of the swab of Figure 1 A;

[0032] Figure IF is a lateral cross-section of the head of the swab of Figure 1 A illustrating the hub and spines of the head according to some embodiments;

[0033] Figure 1G is a proximal end view of the swab of Figure 1A;

[0034] Figure 1H is a close-up side view of a breakpoint portion of the swab of Figure 1A, according to some embodiments; and

[0035] Figure 2 is a schematic diagram of a test kit comprising a swab according to some embodiments;

[0036] Figure 3A is a perspective view of a swab, according to some embodiments; [0037] Figure 3B is a side view of the swab of Figure 3A;

[0038] Figure 3C is a close up side view of the head of the swab of Figure 3A;

[0039] Figure 3D is a proximal end view of the swab of Figure 3A; [0040] Figure 4A is a plot showing Cycle threshold (Ct) values for detecting the SARS-CoV-2 E gene with various swab types at Viral concentration, 160 plaque forming unit (PFU) equivalents/mL;

[0041] Figure 4B is a plot showing Cycle threshold (Ct) values for detecting the SARS-CoV-2 E gene with various swab types at Viral concentration, 16 PFU equivalents/mL.

[0042] Figure 4C is a plot showing Cycle threshold (Ct) values for detecting the SARS-CoV-2 E gene with various transport media using Design G 3D-printed swab, at Viral concentration, 160 PFU equivalents/mL;

[0043] Figure 4D is a plot showing Cycle threshold (Ct) values for detecting the SARS-CoV-2 E gene with various transport media using Design G 3D-printed swab, at Viral concentration, 16 PFU equivalents/mL; and

[0044] Figure 5 shows results for a Clinical evaluation study: Cycle threshold (Ct) values for RNAse P detection in nasal samples collected from fifty hospital staff members with Copan ESwabs or design G 3D-printed swabs..

Description of Embodiments

[0045] Embodiments generally relate to a swab and a kit comprising the swab. The swab may be used to collect a fluid sample from a patient for testing. For example, the swab may comprise a nasopharyngeal swab.

[0046] Referring to figures 1A to 1H, a swab 100 is shown, according to some embodiments. The shape and dimensions of the swab 100 make it suitable for use as a nasopharyngeal swab, though dimensions and proportions may be varied for other applications. All dimensions in the present disclosure are provided for exemplary purposes only.

[0047] The swab 100 comprises a handle 101 and a head 110. In some embodiments, the swab comprises a neck 111 extending between and connecting the head 110 and the handle 101. The head 110 comprises a plurality of spines 112 protruding radially away from a central hub 114 of the head 110 relative to a longitudinal axis 102 of the swab 100.

[0048] The spines 112 may alternatively be referred to as protrusions, protuberances, tines, fingers or nodes. The spines 112 may be substantially cylindrical with a rounded tip. For example, the spines may have hemispherical tips.

[0049] Each of the spines 112 may have a length in the range of 1mm to 1.6mm, 1.2mm to 1.4mm or about 1.3mm, for example. Each of the spines 112 may have a diameter in the range of 0.5mm to 1.3mm, 0.5mm to 0.7mm, or about 0.6mm, or about 0.7mm, for example.

[0050] In some embodiments, all of the spines 112 of the swab head 110 may be substantially identical to each other. In other embodiments, some of the spines 112 of the swab head 110 may be different from others of the spines 112. [0051] The head 110 may be generally cylindrical in shape with tips of the spines 112 mapping onto an imaginary cylindrical surface defining the radial extent of the head.

[0052] The portion of the head 110 comprising the spines 112 may have a length in the range of 12mm to 25mm, 17mm to 21mm, or about 20 mm. A maximum diameter of the head 110 defined by the maximum tip-to-tip span of the spines 112 may be in the range of 2mm to 4mm, 3mm to 4mm, 3.5mm to 4mm, 3.7mm to 3.9mm, or about 3.8mm.

[0053] The hub 114 may have a diameter in the range of 0.5mm to 2mm, 0.8mm to 1.6mm, or about 1.2mm. The hub diameter may be in the range of 10% to 50%, 20% to 40%, 25% to 35%, or about 30% of the maximum diameter of the head 110.

[0054] The spines 112 may be arranged in a series of similar rows 120, each row of spines extending circumferentially around the hub 114 with a similar angle of separation between the spines of each pair of adjacent spines in the row.

[0055] The number of spines in each row may be in the range of 4 to 10 spines, 5 to 8, spines, 5 to 7 spines or 6 spines, for example. The number of rows of spines may be in the range of 10 to 30, 15 to 25 or about 20.

[0056] The angle of separation between the spines 112 may be in the range of 45 degrees to 90 degrees, 50 degrees to 70 degrees or about 60 degrees, for example.

[0057] Each row 120 may be axially spaced from the next adjacent row 120 along the longitudinal axis 102 by a distance or pitch in the range of 0.5mm to 1.5mm, 0.75mm to 1.5mm, 0.8mm to 1.2mm or about 1mm.

[0058] In some embodiments, the spines 112 may be arrange in a different pattern, such as a helical arrangement, for example. In which case the pitch between adjacent spines in a direction along the longitudinal axis 102 may be in the range of 0.5mm to 1.5mm, 0.75mm to 1.5mm, 0.8mm to 1.2mm or about 1mm. [0059] The spines 112 of each row 120 may be angularly offset about the longitudinal axis 102 (i.e., in an azimuthal direction) from the next adjacent row 120 along the longitudinal axis 102. This offset angle is illustrated in Figures IE and IF between a first row 120a and a second row 120b, for example.

[0060] The offset angle between adjacent rows 120 may be a fraction of the angle of separation between spines 112 within a row 120. Such as half, one third or one quarter of the angle of separation between spines within a row.

[0061] The number of spines 112 per length along the longitudinal axis 102 may be in the range of 4 to 16 spines per millimetre, 4 to 10 spines per millimetre, 5 to 8 spines per millimetre, or about 6 spines per millimetre.

[0062] The number of spines per area relative to the surface area of an imaginary cylindrical surface defining the radial extent of the spines may be in the range of 0.5 to 2.5 spines per square millimetre, 0.7 to 2.1 spines per square millimetre, 1 to 2 spines per square millimetre, 1.5 to 2 spines per square millimetre, 1.8 to 2 spines per square millimetre, 0.5 to 1.5 spines per square millimetre, 0.8 to 1.2 spines per square millimetre, about 1.9 spines per square millimetre, or about 1 spines per square millimetre.

[0063] The head 110 may further comprises a rounded distal tip 116. The distal tip 116 may be devoid of spines. The distal tip 116 may be hemispherical or part spherical. The rounded distal tip 116 may facilitate smooth insertion of the swab 100 into the nasal and/or pharyngeal passages of a patient and reduce discomfort for the patient compared to previous swab designs.

[0064] A maximum diameter of the distal tip 116 is less than a maximum tip-to-tip span of the spines (the maximum diameter of the head). The maximum diameter of the distal tip 116 may be in the range of 1mm to 3mm, 1mm to 2mm, 1.5mm to 2.5mm, 1.8mm to 2.2mm or about 2mm. The maximum diameter of the distal tip 116 may be in the range of 20% to 80%, 30% to 70%, 40% to 60%, or about 50% of the maximum diameter of the head 110.

[0065] The swab 100 may further comprise a tapered portion 118 connecting the head 110 to the neck 111. The tapered portion 118 may facilitate smooth removal of the swab head 110 from the nasal and/or pharyngeal passages of the patient and reduce discomfort for the patient compared to previous swab designs.

[0066] A maximum diameter of the tapered portion 118 may be less than the maximum tip-to-tip span of the spines (or the maximum head diameter), and the tapered portion 118 tapers down to match the diameter of the neck 111. A maximum diameter of the tapered portion 118 may be in the range of 50% to 95%, 60% to 90%, 70% to 90%, 75% to 85%, or about 80% of the maximum diameter of the head 110.

[0067] The tapered portion 118 may be conical with a taper angle in the range of 5 degrees to 30 degrees, 7 degrees to 20 degrees, 9 degrees to 13 degrees, or aboutll degrees.

[0068] The neck may be substantially cylindrical. The diameter of the neck 111 may be in the range of 0.8mm to 1.4mm, 0.8mm to 1.2mm, 0.9mm to 1.1mm or about 1mm. The length of the neck 111 may be in the range of 17.5mm to 27.5mm, 19mm to 23mm, about 22mm, or about 21.75mm. The neck 111 may be similar in length or longer than the length of the head 110.

[0069] The swab may further comprise a break-off portion 105 connecting and extending between the handle 101 and the neck 111. This may facilitate safe storage of the swab head 110 in a vial along with the fluid sample taken from the patient.

[0070] Once the swab head 110 has been inserted and removed from the patient, the head 110, neck 111 and break-off portion 105 may be inserted into the vial and the handle 101 bent down against a rim of the vial so as to break the break-off portion away from the handle 101. This allows the head 110, neck 111 and break-off portion 105 to be stored in the vial while the handle 101 is discarded.

[0071] The break-off portion 105 may be connected to the handle 101 by a breakpoint portion 106. The breakpoint portion 106 is narrower in diameter than the break-off portion 105 and the handle 101, so as to encourage breaking at the breakpoint rather than the handle 101, break-off portion 105 or neck 111.

[0072] The breakpoint portion 106 may have a larger diameter than a diameter of the neck 111. The breakpoint portion 106 diameter may be about 1.2mm. The breakpoint portion 106 diameter may be larger than the diameter of the neck 111 by at least 5%, at least 10%, at least 20%, at least 30%, 20% to 50%, about 20%, or about 30%. This may provide sufficient stiffness in the breakpoint portion 106 to allow good control of the swab head 110 while holding the handle 101, while also allowing sufficient flexibility in the neck 111 for bending around curves in the nasopharyngeal passage.

[0073] The transitions 107 between the breakpoint portion 106, the handle 101, and the break-off portion 105 may be radiused, as shown in Figure 1H. That is, instead of having a sharp edge at either end of the breakpoint portion 106, the edge may be smoothed or rounded. This may reduce the likelihood of the breakpoint 106 breaking at the transitions 107 and instead focus stress towards the centre of the breakpoint portion 106. This allows for more precision when breaking off the break-off portion 105, which facilitates capping of the vial containing the swab head 110, neck 111 and break-off portion 105.

[0074] The length of the breakpoint portion 106 (not including transitions 107) may be in the range of 1.5mm to 2.5mm, 1.6mm to 2mm, 1.7mm to 1.9mm or about 1.8mm.

[0075] The total length of the swab head 110, neck 111 and break-off portion 105 may be designed specifically to fit into a certain vial. The depth of the vial may be in the range of 40mm to 100mm, 60mm to 80mm, about 70mm or about 75mm. The total length of the swab head 110, neck 111 and break-off portion 105 may be in the range of 40mm to 100mm, 60mm to 80mm, 75mm to 80mm, about 80mm, about 70mm or about 75mm.

[0076] Referring to Figure 2, a test kit 200 is shown according to some embodiments. The test kit 200 comprises a swab 100 according to any one of the described embodiments.

[0077] The swab 100 may be enclosed in a sterile package 210, which may be sterilized with an autoclave, gamma radiation, or Ethylene oxide sterilization.

[0078] The test kit 200 may further comprise a vial 220 containing a transport medium and configured to receive and enclose part of the swab 100. The vial 220 may comprise 2-3mL of transport medium. For example, the transport medium may comprise saline, Universal Transport Medium, liquid amines, or Viral Transport Medium, depending on the application.

[0079] A length of the vial 220 may be similar to or slightly larger than a total length of the swab head 110, neck 111 and break-off portion 105 when separated from the handle 101.

[0080] The test kit 200 may further comprise a sample package 230 (such as a biohazard bag, for example) to receive the vial 220 containing the swab 110 once the fluid sample has been taken. The test kit 200 may further comprise a procedure package 202 to accommodate the swab 100, sterile package 210, vial 220 and sample package 230. The procedure package 202 may or may not be sterilised depending on the application of the test kit 200.

[0081] Referring to Figures 3A to 3D a swab 300 is shown, according to some embodiments. The swab 300 may be similar to swab 100 in many respects, with like features indicated with like reference numerals. The swab 300 may comprise any one or more of the features described in relation to swab 100 including the described variations in structures, geometries, dimensions and configuration. [0082] The swab 300 comprises a handle 101, a head 110, and a neck 111 extending between and connecting the head 110 and the handle 101. The head 110 comprises a plurality of spines 112 protruding radially away from a central hub 114 of the head 110 relative to a longitudinal axis 102 of the swab 300.

[0083] The spines 112 may comprise any of the shapes, dimensions and configurations described in relation to swab 100. For example, the spines 112 may be substantially cylindrical with a rounded tip, and arranged in alternating angularly offset rows of 6 evenly spaced spines 112, as shown in Figures 3C and 3D, in a similar arrangement to that of swab 100 as shown in Figures 1C to IF.

[0084] The spines 112 shown in Figures 3C and 3D are slightly larger in diameter than the spines 112 shown in Figures 1C to IF; 0.7mm and 0.6mm, respectively. However, any suitable diameter may be chosen for the spines 112.

[0085] The head 110 may be generally cylindrical in shape with tips of the spines 112 mapping onto an imaginary cylindrical surface defining the radial extent of the head.

[0086] The head 110 may further comprises a distal tip 116. The distal tip 116 may be devoid of spines. The distal tip 116 may be rounded to facilitate smooth insertion of the swab 100 into the nasal and/or pharyngeal passages of a patient and reduce discomfort for the patient compared to previous swab designs.

[0087] The distal tip 116 shown in Figures 3 A to 3D differs from the distal tip 116 shown in Figures 1A to IE in that it is larger in diameter and comprises a flat disc shape rather than a hemispherical shape.

[0088] The distal tip 116 of swab 300 defines a flat surface 116a, perpendicular to the longitudinal axis 102, and a rounded edge 116b extending circumferentially around the flat surface 116a. The radius of curvature of the rounded edge 116b in a plane parallel to the longitudinal axis 102 may be in the range of 0.3mm to 3mm, 0.5mm to 2mm, 0.8mm to 1.2mm or about 1mm, for example. [0089] A maximum diameter of the distal tip 116 may be similar to or equal to a maximum tip-to-tip span of the spines (the maximum diameter of the head). The maximum diameter of the distal tip 116 may be slightly larger or slightly smaller than the maximum tip-to-tip span of the spines 112. The lateral radial extent of the distal tip 116 may be similar or equal to the lateral radial extent of the spines 112. The maximum diameter of the distal tip 116 may be in the range of 80% to 105%, 90% to 103%, 95% to 102%, or 98% to 101% of the maximum tip-to-tip span of the spines 112 or the diameter of a cylindrical envelope defined by the tips of the spines 112.

[0090] The swab 300 may comprise any of the features described in relation to swab 100 and may form part of a kit, as described in relation to kit 200, instead of swab 100.

[0091] The swab 100, 300 may be formed of a polymer material, such as a thermosetting plastic. The swab 100 may be formed of a material comprising nylon.

The material may comprise nylon 12, for example, (or PA 2200 Balance 1.0 PA12).

The swab 100 may be formed as a single contiguous piece of material.

[0092] The swab 100, 300 may be formed by selective laser sintering. For example, the swab 100, 300 may be formed with selective laser sintering using EOS P396 (Electro Optical Systems). Tensile strength may be lesser in the z-direction when building up a part with selective laser sintering. Therefore, it may be preferable to fabricate the swab 100, 300 with the longitudinal axis 102 aligned horizontally, i.e., in the x-y plane perpendicular to the z-direction.

[0093] The table below shows the technical specifications for Nylon 12 material fabricated with selective laser sintering.

[0094] It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive Validation studies

In vitro validation

[0095] The swab 100 shown in Figures 1 A to 1H (also referred to as “design G” below) was tested and compared with conventional flocked swabs in their effectiveness in collecting patient samples.

[0096] The recovery of SARS-CoV-2 from different transport media using the design G swabs was assessed, and compared with that of two swabs currently used in Australia to collect specimens for SARS-CoV-2 testing. The following swab/transport medium combinations were assessed:

- flocked Copan ESwabs and liquid Amies medium (Copan; catalogue number 480CE);

- flocked Kang Jian swabs and viral transport medium (Kang Jian Medical; catalogue number KJ502-19);

- design G 3D-printed swabs and viral transport medium (University of Melbourne Media Preparation Unit; product number 2512);

- design G swabs and liquid Amies medium (University of Melbourne Media Preparation Unit; product number 2162); and

- design G swabs and normal saline.

[0097] Virus stock (SARS-CoV-2 strain VICOOl; circa 10^L7 copies/mL) was prepared in minimum essential medium (Sigma) containing 2% foetal bovine serum (Gibco), and gamma-irradiated to allow subsequent handling in PC2 (physical containment level 2) conditions.

[0098] The mock sample matrix of nasopharyngeal swabs consisted of 20 mL pooled nasopharyngeal swab samples collected in liquid Amies medium from patients negative for SARS-CoV-2 by RT-PCR; 10 mL aliquots of the pooled sample were spiked with gamma-irradiated SARS-CoV-2 to produce two different viral concentrations (16 or 160 plaque-forming unit [PFU] equivalents/mL). [0099] Two swabs for each swab/medium combination listed above were swizzled in 500 pL aliquots of spiked mock sample at each concentration for five seconds, then immediately placed into 2 mL of the corresponding transport medium (liquid Amies, viral transport medium, or normal saline).

[0100] Samples were tested for SARS-CoV-2 by RT-PCR at time zero, 24 hours, and 48 hours; between assays, samples were stored at 4°C. Viral RNA was extracted with the QIAamp 96 vims QIAcube HT kit (QIAGEN); RT-PCR for the envelope protein (E) gene was performed with previously published primers and probes. {Corman VM, Landt O, Kaiser M, et al. Detection of 2019 novel coronavirus (2019-nCoV) by real time RT-PCR. Euro Surveill 2020; 25: 2000045.}

Clinical evaluation

[0101] The performance and tolerability of 3D-printed swabs (design G) was compared with those of standard swabs (Copan ESwabs). The participants were hospital staff members attending a COVID-19 screening clinic at the Royal Melbourne Hospital and inpatients with laboratory-confirmed COVID-19.

[0102] A flocked nasopharyngeal swab sample was collected with the Copan ESwab and a mid-nasal sample from the other nostril with the 3D-printed swab (design G); each swab was placed into 1 mL liquid Amies transport medium. The order of collection was randomised 1:1. Participants were asked to complete a brief survey about their level of discomfort with each swab.

[0103] Nucleic acid was extracted and SARS-CoV-2 RT-PCR performed as described above. In addition, samples from inpatients with laboratory-confirmed COVID-19 were assessed for SARS-CoV-2 by RT-PCR using the Xpert Xpress SARS-CoV-2 assay (Cepheid) according to the manufacturers’ instructions. Semi-quantitative real time RT- PCR detection of a human housekeeping gene (RNase P) served as a surrogate marker for the amount of cellular material derived from each swab. Statistical analysis

[0104] Differences between samples collected with control and 3D-printed swabs (design G) in RNAse P cycle threshold (Ct) values (a lower Ct value indicates fewer PCR cycles were required for detection, and therefore higher target concentrations) were assessed in a Wilcoxon matched pairs rank test undertaken in R 3.5.1; plots were prepared with GraphPad Prism 8.4.2.

Results

In vitro performance

[0105] Qualitative agreement with respect to detecting SARS-CoV-2 using Copan ESwabs, Kang Jian swabs, and design G 3D-printed swabs in the three transport media was complete; SARS-CoV-2 was detected at both concentrations, at all three time points, and with each swab/medium combination as shown in Table 1 below.

[0106] Table 1. In vitro validation study: SARS-CoV-2 E gene cycle threshold values for mock nasopharyngeal samples, by swab types and transport medium (two samples for each combination) PFU = plaque-forming units.

[0107] Differences between the three swab types in Ct values for E gene detection at each concentration and each of the three time points were negligible (see Figures 4A and 4B). In addition, Ct values for E gene detection using the 3D-printed swab (design G) were similar for each of the three transport media (see Figures 4C and 4D).

[0108] Figures 4A to 4D show Cycle threshold (Ct) values for detecting the SARS- CoV-2 E gene.

By swab type:

- 4A. Viral concentration, 160 plaque-forming unit (PFU) equivalents/mF;

- 4B. Viral concentration, 16 PFU equivalents/mF. and by transport medium using Design G 3D-printed swab:

- 4C. Viral concentration, 160 PFU equivalents/mF;

- 4D. Viral concentration, 16 PFU equivalents/mF.

(Fines mark mean Ct values.)

Clinical evaluation and acceptability

[0109] SARS-CoV-2 E gene was not detected by RT-PCR in nasal swabs (one nostril each with a Copan ESwab and a design G 3D-printed swab) collected from 50 hospital staff who attended a COVID-19 screening clinic at Royal Melbourne Hospital. Qualitative agreement between the Copan ESwab and 3D-printed swab for RNase P detection by RT-PCR was complete, and the distribution of Ct values for the two swab types were similar (ESwabs: median, 27.2; interquartile range [IQR], 26.4-29.0; design G 3D swabs: median, 27.1; IQR, 25.7-28.3; see Figure 5).

[0110] Figure 5 shows results for the Clinical evaluation study: Cycle threshold (Ct) values for RNAse P detection in nasal samples collected from fifty hospital staff members with Copan ESwabs or design G 3D-printed swabs. Fines represent the median and interquartile range Ct values (ns=not significant).

[0111] Three paired swabs were collected from two patients with laboratory- confirmed COVID-19 admitted to Royal Melbourne Hospital. Qualitative agreement between the Copan ESwab and design G 3D-printed swab for SARS-CoV-2 E gene detection by RT-PCR and with the Xpert Xpress SARS-CoV-2 assay was complete as shown in Table 2 below.

[0112] Table 2. SARS-CoV-2 results for samples collected from two patients with laboratory-confirmed COVID-19 infections (*Two samples collected from same patient more than 24 hours apart).

[0113] The 52 study participants scored the discomfort experienced with the design G 3D-printed swab (median, 5 points on a 10-point scale; IQR, 4-6 points) and the Copan ESwab (median, 5 points; IQR, 3-6) similarly; 35 participants (67%) preferred the design G 3D-printed swab, ten (19%) the Copan ESwab, and eight had no preference (15%). Health care providers described the swabs as easy to use, moderately easy to snap at the breakpoint, and as providing a good balance between flexibility and rigidity. Two of the four health care providers involved preferred the 3D-printed swab, and two had no preference..

Claims

CLAIMS:

1. A swab comprising a handle, a head, and a neck extending between and connecting the head and the handle, the head comprising a plurality of spines protruding radially away from a central hub of the head relative to a longitudinal axis of the swab.

2. The swab of claim 1, wherein the spines are substantially cylindrical with a rounded tip.

3. The swab of claim 1 or 2, wherein the spines are arranged in a series of similar rows, each row of spines extending circumferentially around the hub with a similar angle of separation between the spines of each pair of adjacent spines in the row.

4. The swab of claim 3, wherein each row is angularly offset about the longitudinal axis from the next adjacent row along the longitudinal axis.

5. The swab of claim 4, wherein the offset angle between adjacent rows is substantially equal to half of the angle of separation between spines within a row.

6. The swab of any one of claims 1 to 5, wherein the number of spines per length along the longitudinal axis is in the range of 4 to 10 spines per millimetre.

7. The swab of any one of claims 1 to 6, wherein the number of spines per area relative to the surface area of an imaginary cylindrical surface defining the radial extent of the spines is in the range of 0.5 to 2.5 spines per square millimetre.

8. The swab of any one of claims 1 to 7, wherein the head further comprises a rounded distal tip devoid of spines.

9. The swab of claim 8, wherein a maximum diameter of the distal tip is less than a maximum tip-to-tip span of the spines.

10. The swab of any one of claims 1 to 9, further comprising a tapered portion connecting the head to the neck, wherein a maximum diameter of the tapered portion is less than a maximum tip-to-tip span of the spines, and the tapered portion tapers down to match the diameter of the neck.

11. The swab of any one of claims 1 to 10, further comprising a break-off portion connecting and extending between the handle and the neck, the break-off portion being connected to the handle by a breakpoint portion

12. The swab of claim 11, wherein the breakpoint portion has a larger diameter than a diameter of the neck.

13. The swab of claim 11 or 12, wherein transitions between the breakpoint portion, the handle, and the break-off portion are radiused.

14. The swab of any one of claims 1 to 13, wherein the swab is formed of a material comprising nylon.

15. The swab of claim 14, wherein the material comprises nylon 12.

16. The swab of any one of claims 1 to 15, wherein the swab is formed as a single contiguous piece of material.

17. The swab of claim 16, wherein the swab is formed by selective laser sintering.

18. A test kit comprising a swab according to any one of claims 1 to 17.

19. The test kit of claim 18, further comprising a vial containing a transport medium and configured to receive and enclose part of the swab.

20. The test kit of claim 19, when directly or indirectly dependent on claim 11, wherein a length of the vial is similar to a total length of the swab head, neck and break-off portion when separated from the handle.

21. Any one of the structures, features, integers and/or elements disclosed herein or indicated in the specification of this application, or any combination of two or more of said structures, features, integers and/or elements.