Guidance on how to do COVID antigen tests, what to do after testing positive

Writer: Zhang Yu  |  Editor: Zhang Chanwen  |  From: Shenzhen Daily  |  Updated: 2022-12-14

Q&A about COVID rapid antigen tests

1. After being infected with the Omicron variant, how long will rapid antigen tests show a result?

An antigen test is faster and more convenient. However, rapid antigen tests will generally show a result when the virus replicates to higher levels and there is a high viral load detected in an infected person.

According to Omicron’s incubation period, it can be detected two to three days after infection. It may take five days or even longer for some infected people, especially asymptomatic infections, due to continued low viral loads and other reasons.

2. If the antigen test results come out negative, does it mean there is no infection?

If the virus has not been replicated to a high level and excreted from the body and cannot reach the sensitivity of antigen tests, the results will be negative. Thus, some people may have been infected, or even have some mild symptoms, but the antigen test results still come out negative. However, the viral load is usually low, and the infectivity is weak.

There is no need to take antigen tests twice or even three times a day. If necessary, take one test a day.

3. Why do some people show positive antigen test results but negative nucleic acid test results?

The sensitivity of the two testing methods is different, and the sampling operation is not necessarily standard. Generally speaking, the accuracy of nucleic acid testing is higher.

One can end home quarantine if the symptoms are obviously improved or there is no obvious symptom, the results of an antigen self-test and two consecutive nucleic acid tests (the interval between the two tests is more than 24 hours) come out negative.

4. What should we do if the antigen test result is positive?

If the antigen test result is positive, and there are no symptoms or mild symptoms, the patient can quarantine at home and take appropriate medicines for treatment according to the medication guidelines. However, when the symptoms get worse, they must go to medical institutions’ fever clinics in a timely manner.

If senior citizens have positive antigen test results, they must choose medicines under the guidance of medical workers. When the symptoms get worse, they must go to tertiary hospitals in a timely manner.

In addition, if the antigen test result is positive, report the result to the grassroots medical institutions as required.

Q&A about testing positive for COVID

1. Is it an asymptomatic infection if one tests positive for COVID and only has symptoms of cough and fever?

If one tests positive for COVID and only has symptoms of cough and fever without a pulmonary infection, it can be classified as a mild case, but it is not an asymptomatic infection.

Current national data shows that over 90% of those infected with Omicron are asymptomatic or mild cases.

According to the current definition, asymptomatic infections refer to those who are positive in a pathogenic COVID-19 test and have no relevant clinical manifestations such as fever, dry cough, fatigue, sore throat, hypoesthesia (sensory loss) and diarrhea that can be perceived or indentified clinically, and have no certain CT imaging features.

Mild COVID patients may show symptoms of upper respiratory tract infection such as moderate and low-grade fever, dry throat, sore throat, nasal congestion, runny nose, as well as fatigue, loss of smell or taste, but not pneumonia symptoms.

2. Will COVID patients test positive again? How long until a secondary infection can possibly occur?

After infection with COVID, the immunity formed by the human body will play a protective role. However, Omicron may quickly mutate into new subvariants that have a strong ability to escape the immune system, so recovered COVID patients cannot completely avoid a secondary infection.

However, statistics from foreign countries show that the probability of a secondary infection within 3 to 6 months is quite low, regardless of whether there are symptoms after people are infected with Omicron. Most people will not be repeatedly infected with Omicron over a long period of time.

For individuals, the best way during the epidemic is to maintain protective measures, including wearing a mask, observing hand hygiene, keeping social distancing and getting vaccinated to reduce the risk of infection.

3. Does repeated infection make the symptoms even worse?

At present, there is no final conclusion that a repeated infection will lead to more serious clinical symptoms. From current cases, even if individual patients tend to experience aggravated symptoms when repeatedly infected, the number is also very low.

The pathogenicity of Omicron is weakening. Whether it is the first or secondary infection, the probability of developing severe illness is very low.