Exhaled Breath Condensate vs Nasal Swab Sampling
In January 2024, a VosBio™ employee tested positive for SARS-CoV-2 using an FDA-approved at-home molecular test that employs a nasal swab. Over the next 2 weeks, breath and nasal swab samples were collected and tested for the presence of virus. Breath samples were tested using VosBio LAMP and qPCR protocols, while nasal swab samples were tested using the same FDA-approved at-home molecular test, as well as a lateral-flow antigen test.
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VosBio™ qPCR was able to quantify the amount of virus being shed each minute in the employee’s breath, which ranged from 0 – 4,000 copies per minute. VosBio’s™ LAMP protocol gave rapid results within 20 minutes, indicating the presence of virus in every sample above 30 copies per minute.​​
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While the FDA-approved molecular test detected the virus on most days during the study, it did not correlate with the days in which the employee was most infectious. At various times it failed to detect virus when the employee was highly infectious, and it continued giving positive results after viral shedding in the breath had subsided.
While the at-home molecular test is sensitive and reliable in detecting whether the virus is present, the sampling method means that it does not detect infectiousness. There is no correlation between the amount of virus present in the breath and the amount present in the nose. Generally the viral load in the breath peaks days earlier than in the nose, before symptoms are present.
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Throughout this period, the employee never experienced COVID symptoms, and the FDA-approved antigen test never detected the virus. If the employee had not taken the initial molecular test, there would be no indication that he was infected or infectious.
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A large percentage of viral transmission begins in pre-symptomatic or asymptomatic individuals [2]. To break the chain of transmission, people without symptoms must be tested for infectiousness before engaging in activities prone to spread the virus. Fortunately, VosBio’s™ breath collection system is fast, comfortable, and cost-effective enough for widespread use.
Exhaled Breath Condensate vs Saliva
Researchers and public health officials looking for simpler, less invasive sampling methods often turn to either saliva or Exhaled Breath Condensate (EBC). While these two sample types initially seem similar, there are important practical differences. EBC is an extremely clean sample, suitable for analysis with little or no preparation. Saliva contains a complex mix of cells, mucus, enzymes and a wide range of organic compounds. This mixture can complicate any analysis, so typical protocols using saliva are typically purified to isolate the compounds of interest.
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Compared with saliva, EBC is an extremely clean sample matrix that is easy to process and analyze.
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​The VosCryo™ breath collector does not allow a significant amount of saliva into the EBC sample. Users breath through the tube at a comfortable angle, approximately horizontal. This prevents any saliva from dripping into the sample due to gravity. Sample times are low stress and very short, typically under a minute. This prevents saliva from accumulating over time, while breath condensate is rapidly collected. Finally, the VosCryo™ system's patented reverse-flow collection allows breath to condense efficiently over a wide surface area, while saliva is captured in the mouthpiece.
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