COVID-19 Facts

FUNDAMENTAL STRUCTURE

The novel coronavirus, is a virus belonging to the family Coronaviridae, with approximately 120 nm in diameter.

Club-shaped glycoprotein spikes in the envelope give the viruses a crownlike, or coronal, appearance.

The nucleocapsid, made up of a protein shell known as a capsid and containing the viral nucleic acids, is helical or tubular. The coronavirus genome consists of a single strand of positive-sense RNA [ribonucleic acid).

The N antigen (N protein) is a component protein of nucleocapsid of SARS-Cov-2, with molecular weight of about 46kDa. It is highly conserved and rich in the virus. Currently, N protein is an ideal detection marker of SARS-COV-2.

REPLICATION IN THE CELL

For some RNA viruses, the infecting RNA produces messenger RNA (mRNA). This is translation of the genome into protein products. For others with negative stranded RNA and DNA, viruses are produced by transcription then translation. The mRNA is used to instruct the host cell to make virus components.

SYMPTOMS OF COVID-19 PATIENTS

The signs and symptoms of COVID-19 present at illness onset vary, but over the course of the disease, most persons with COVID-19 will experience the following: Fever,Cough, Fatigue, Anorexia, Shortness of breath, Sputum production and Myalgia. Atypical symptoms such as headache, confusion, rhinorrhea, sore throat, hemoptysis, vomiting, and diarrhea.

DIAGNOSTIC METHODS

qPCR Nucleic Acid Detection

PCR nucleic acid detection can be used to diagnose COVID-19 in the early stage, which is a common diagnostic method at present. But the detection process is complex, and there will be false negative and false positive problems.

Main Reasons for False Negative:

Sampling Deviation
Low Viral Load
Difference in different course and parts

Main Reason of False Positive:
The experimental process is complex and prone to cross contamination.

SARS-CoV-2 Antigen Detection

The rapid antigen test is based on the detection of viral protein in respiratory sample materials. Simple and uncomplicated quick tests use a lateral flow strip in a test cassette for immediate visual evaluation on site. Antigen tests are a useful addition to the qPCR test where a first decision about the possible existence of a transmission-relevant infection in a person should be made quickly in the early phase of the infection (WHO, 2020a). The prerequisite for proper application with regard to the intended support of the questions that arise in practice is a sensitivity of the respective test, which indicates an infection from the beginning of the virus in the upper respiratory tract to the end of the contagiousness of the person concerned. The results of comparative studies or clinical studies in the practical application of the test are decisive for this. The performance parameters of the current antigen test make it possible to use it for clearly defined questions, thereby relieving the qPCR diagnostics and shortening the time to diagnosis. The CoV-2 antigen rapid test presented here fulfills this definition.