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.
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