ImportanceReal-world evidence of SARS-CoV-2 transmission is needed to understand the prevalence of infection in the Japanese population.ObjectiveTo conduct sentinel screening of the Japanese population to determine the prevalence of SARS-CoV-2 infection in asymptomatic individuals, with complementary analysis for symptomatic patients as reported by active epidemiologic surveillance used by the government.Design, Setting, and ParticipantsThis cross-sectional study of a sentinel screening program investigated approximately 1 million asymptomatic individuals with polymerase chain reaction (PCR) testing for SARS-CoV-2 infection between February 22 and December 8, 2021.

Amongst the multiple ways to diagnose coronavirus disease-2019 (COVID-19), reverse transcription polymerase chain reaction (RT-PCR) remains the reference gold standard, providing fast and accurate results.

The initial (and still most commonly used antigen tests) for COVID-19 diagnosis were constructed using monoclonal antibodies (mAbs) specific to severe acute respiratory syndrome coronavirus (SARS-CoV) nucleocapsid protein (NP).

Saliva samples and a cycle threshold (Ct) value of approximately 40 as standard in Japan were used.

Among these, severe acute respiratory syndrome (SARS-CoV) and Middle East respiratory syndrome (MERS-CoV) have posed significant threats to human health in the past.

The initial (and still most commonly used antigen tests) for COVID-19 diagnosis were constructed using monoclonal antibodies (mAbs) specific to severe acute respiratory syndrome coronavirus (SARS-CoV) nucleocapsid protein (NP).

The sensor has a response time of 5 min with a limit of detection (LOD) reaching 200 and 500 pM for the freely suspended spike (S) protein in phosphate buffer saline (PBS) and human saliva, respectively.

Nasopharyngeal swabs were collected from suspected cases and were tested using the Abbott SARS-CoV-2 kit, a rapid diagnostic test (RDT) and compared to the reference standard RT-PCR.

In all RT-PCR positive samples, COVID-VIRO ALL IN displayed 78.8% agreement, 0.698 sensitivity, 1.000 specificity, 0.583 negative predictive value (NPV) and 1.000 positive predictive value (PPV) compared to RT-PCR.

A label-free rapid electrochemical point-of-care (POC) biosensor for SARS-CoV-2 detection in human saliva is reported here to help address the shortcomings of traditional nucleic acid amplification methods and give a quantitative assessment of the viral load to track infection status anywhere, using disposable electrochemical sensor chips.