If I have a cold or flu, will the nucleic acid and antigen tests be positive?

[This issue's rumors]:

Recently, there has been a claim that after catching a common cold or flu, a nucleic acid or antigen test will also be positive. Many people are skeptical and worried about this. So, what is the truth?

【NetEase Health Assessment】：

rumor!

【Rumor Identification Points】:

1. Colds, flu, and COVID-19 are caused by different viruses

In terms of symptoms, colds, flu, and new coronavirus infections may all cause fever, cough, headache, etc., but these three diseases are caused by different viruses:

Colds: Generally caused by pathogenic microorganisms such as bacteria, viruses, mycoplasma, chlamydia, rickettsia, etc. Among them, viruses are mostly rhinovirus, parainfluenza virus, respiratory syncytial virus, adenovirus, etc.

Flu: caused by influenza virus. Influenza virus belongs to the family Orthomyxoviridae and is a single-stranded, negative-stranded, segmented RNA virus. It is divided into four types: A, B, C, and D according to the difference in nucleoprotein and matrix protein. Currently, the main types that infect humans are the H1N1 and H3N2 subtypes of influenza A virus and the Victoria and Yamagata strains of influenza B virus.

COVID-19: caused by the 2019 novel coronavirus (2019-nCoV). 2019-nCoV is the seventh known coronavirus that can infect humans. The other six are HCoV-229E, HCoV-OC43, HCoV-NL63, HCoV-HKU1, SARS-CoV (which causes severe acute respiratory syndrome), and MERS-CoV (which causes Middle East respiratory syndrome).

2. Nucleic acid and antigen testing are conducted on the new coronavirus

Nucleic acid testing: Nucleic acid is the general term for deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), which is widely present in all animal and plant cells and microorganisms. The new coronavirus nucleic acid test is based on this principle, using the principle that the nucleic acid of each virus is different to test the unique gene sequence of the new coronavirus.

Antigen testing: Antigen testing is to detect whether there are protein components of the new coronavirus in the specimen. Generally, the test targets the N protein, which is the nucleocapsid protein of the new coronavirus . If there is the new coronavirus N protein in the specimen, it will combine with the specific antibodies in the test plate, and then the test line will show color.

From the above, we can know that both nucleic acid testing and antigen testing target the genetic characteristics of the new coronavirus. Therefore, if the patient simply has a cold or flu and the new coronavirus is not present in the body, then the new coronavirus nucleic acid test or antigen test will not show a positive result.

NetEase Health reminds everyone that wearing masks, paying attention to hygiene, and avoiding gathering can help us stay away from the virus. If suspicious symptoms such as fever, dry cough, fatigue, decreased sense of smell and taste, nasal congestion, runny nose, sore throat, conjunctivitis, myalgia and diarrhea occur, you should seek medical attention immediately.