Q&A about COVID reinfection, second booster shot

Writer: Zhang Yu  |  Editor: Zhang Chanwen  |  From: Shenzhen Daily  |  Updated: 2022-12-23

COVID-19 reinfection has come into focus as some infected people have recovered from COVID. Health experts, including Li Tongzeng from Beijing Youan Hospital, Capital Medical University, Wang Xinyu from Huashan Hospital, Fudan University, and Guo Wei from Tongji Hospital, Huazhong University of Science and Technology, have answered relevant questions.

1. Is it reinfection if one tests positive again after the nucleic acid test has turned negative?

Still testing positive for COVID usually occurs within a short period of time, for instance, two to three week. It means that the nucleic acid test has not completely turned negative.

Reinfection means that a person was infected, recovered, and then later became infected again. It usually occurs at an interval of more than half a year.

2. Why has the nucleic acid test still come out positive?

In clinical practice, it is found that some people have repeated viral shedding, that is to say, viral shedding is intermittent. In some cases, the patient has lung disease or a large viral load. The nucleic acid test has turned negative due to treatment, and then turned positive again after the treatment.

3. Is it contagious if one who still tests positive for COVID or if one is infected with the virus again?

It is generally believed that some fragments of the virus are detected in someone who still tests positive for COVID. The fragments are neither infectious nor pathogenic. If it is a reinfection, it is infectious.

4. Is there a high probability of still testing positive for COVID?

It is unnecessary to pay too much attention to the situation of still testing positive for COVID, because these people usually do not pose a risk of infection to people around them. Based on data, it is common that the test is negative and then positive again. The test result will be stabilized in about a week.

5. Under what circumstances is reinfection more likely to occur?

After one has recovered from an infection, the antibody level in the body will gradually decrease. Meanwhile, if the prevalent viral strains become different, the probability of reinfection will increase.

People with weak immunity are also vulnerable to reinfection. According to the current research data, even if a secondary infection occurs, the body will experience milder symptoms and recover faster.

6. After being infected with the BA5.2 subvariant, will one get infected with the BF.7 subvariant?

Generally speaking, after infection with one virus subvariant, there is still a high level of neutralizing antibodies in the human body in a short period of time. Thus, after infection with the BA5.2 subvariant, the possibility of an infection with the BF.7 subvariant in a short time is relatively low. But taking the long view, there is a possibility that one will be infected repeatedly with different subvariants.

7. Will symptoms worsen after a reinfection?

If the person is infected with subvariants that belong to the same sublineage, the symptoms will be milder and the recovery will be faster. The currently prevalent BA5.2 and BF.7 subvariants belong to the same sublineage.

8. Are the currently prevalent sibvariants cause reinfection easily?

It is generally believed that people with normal immunity will not be reinfected within three to six months.

9. How to avoid reinfection after recovery?

After recovery, good habits such as wearing a mask, washing hands frequently, opening windows more for ventilation and maintaining social distancing and cough etiquette should be continued. In addition to protecting against COVID, masks also have good protection effect against other infectious respiratory diseases.

After the nucleic acid test turns negative, patients should pay close attention to their health. Clothes, bed sheets, towels, tableware and other daily necessities should be used separately.

For people who have not been infected at present, it is better to wear a high-level protective mask such as N95 or KN95 in these one or two months, and avoid gatherings. It is recommended to complete the whole vaccination course as soon as possible, and get a second booster shot if possible.

10. Do I still need vaccination to prevent reinfection after recovery?

There is a possibility of reinfection after recovery. Theoretically speaking, it is still necessary to get vaccinated again. It is advised to wait at least six months after recovery, and consult the doctor to assess whether the body condition is suitable for vaccination.