Q&A on COVID-19 reinfection

The more virulent Delta strain of COVID-19 is not currently circulating in China and the circulating nine strains are all variants of Omicron, according to epidemiological data, experts said.

While many people are recovering from the novel coronavirus infection, some people worry if they could get reinfected quickly. Let's check the facts on reinfection.

1. What is the COVID-19 reinfection?

The COVID-19 reinfection refers to a COVID-19 infection that occurs after a person has recovered from their previous COVID-19 infection.

2. How to determine COVID-19 reinfection?

Different countries or regions have different definitions of the COVID-19 reinfection, but the basic condition is to have a period of time pass between the first and second infection. The interval is defined as at least 90 days in the UK, and 60-90 days or more in the United States.

COVID-19 reinfection is comprehensively determined by considering symptoms, clinical manifestations, immune responses, and other indicators.

3. What is the probability of a COVID-19 reinfection?

The probability of a COVID-19 reinfection is primarily related to one's immunity level and variation in the newly contacted virus strain.

When a person comes into contact with a new strain of the COVID-19 virus, the higher the antibody and other immune reaction indicators, the less the virus strain varies from strains encountered during previous inflections, and the lower the probability of reinfection.

4. How to distinguish rebound positivity from reinfection?

Rebound positivity refers to when a COVID-19 patient's nucleic acid retest is found to be positive again despite no longer having any symptoms of infection and meeting hospital discharge standards.

Patients with rebound positivity generally have no obvious clinical symptoms and are basically not infectious.

COVID-19 reinfection is equivalent to having a new infection. It is being infected a second time after recovery. There may be signs of clinical symptoms after reinfection, and the patient is infectious due to a high nucleic acid load.

5. The relationship between antibody levels and COVID-19 reinfection?

Many studies have shown that vaccination or immunization from natural infections can reduce the probability of COVID-19 reinfection. People with low immunity or low antibody levels are relatively more vulnerable to reinfection.

6. Are the symptoms more severe during COVID-19 reinfections?

The severity of a disease during reinfection may be related to the quantity of the virus, the variation and mutation of the virus, and personal health conditions.

In general, the probability of reinfection leading to more severe symptoms is very low.

7. What kind of people are likely to have COVID-19 reinfections?

In general, people with lower or weaker immunity functions such as elders and children, people with immunodeficiency such as AIDS patients and immunosuppressant users, and people working in high-risk environments such as medical staff and public transport operators, are more likely to have COVID-19 reinfections.

8. Under what circumstances are COVID-19 reinfections likely to occur?

People who have recovered from their previous COVID-19 infection for half a year or longer are more likely to experience a reinfection.

It is also easier to get re-infected when not wearing proper personal protection.

9. How to prevent COVID-19 reinfection after recovery?

Regularly and properly wear face masks, strengthen personal and hand hygiene, and maintain proper social distances.

In addition, after recovering from a COVID-19 infection for at least six months, it is recommended to receive another shot of COVID-19 vaccine to strengthen immunization.