A comprehensive interpretation of secondary infection in COVID-19： What is secondary infection？ Are the symptoms less severe？

How to judge whether you are infected again? Here are some key symptoms:

1. Dyspnea: Dyspnea is one of the most obvious symptoms. If you feel shortness of breath, shortness of breath and wheezing, it may be a sign of secondary infection.

2. High fever: The first infection usually has symptoms of fever, but if your temperature keeps above 38℃ for several days, it may be a second infection.

3. persistent cough: even if you have no symptoms of fever or dyspnea, be alert to persistent cough. If you cough for more than a week, accompanied by fatigue and fatigue, then you may need to consider whether to carry out relevant examinations and tests.

4. Headache and physical discomfort: Some patients may have headaches, body aches and discomfort. If these symptoms appear in the course of the disease and last for several days, then you need to consider whether to have the corresponding examination.

5. Changes in taste or smell: These symptoms are usually one of the early symptoms of Covid-19 infection. If you have regained your sense of smell and taste, but suddenly lose these senses, then you need to consider whether to test it.

The topic of "the second wave of COVID-19" rushed to the hot search, and some netizens also commented that they or their family and friends around them had the phenomenon of "two yang in COVID-19".

In this regard, many people are very scared.Is the second wave of COVID-19 epidemic really coming?

Is the level of COVID-19 antibody in your body enough to resist a new round of Covid-19?

Is there a high probability of secondary infection in COVID-19? Which groups of people are prone to secondary infection? How to distinguish whether you are "relapsing yang" or secondary infection?

How should we treat "Er Yang" rationally?

This paper comprehensively sorts out and answers the hot issues that everyone is highly concerned about at present.

At present, public opinion generally believes that Covid-19 will not disappear in a short period of time, and it may become influenza-like, and "appear sporadically" repeatedly among some people.

Although it has not disappeared, we can deal with it with a mature and calm mind, and do a good job of daily protection, and finally defeat it.

1. Why did the positive cases suddenly increase after May Day?

The press conference of the State Council Joint Prevention and Control Mechanism held on May 8th informed that the national epidemic situation reached the lowest level since November 2022 in early April this year due to the objective law that people’s immunity decayed with time after vaccination and Covid-19 infection, but it began to rise slowly in the near future. Liu Qing, deputy director of the Department of Infectious Disease Prevention and Control of the National Bureau of Disease Control and Prevention, said that the epidemic situation in some areas increased slightly during the May 1 ST period, but the number of severe cases in hospitals in various places did not increase significantly. It is unlikely that there will be a regional and large-scale epidemic, which will not have a significant impact on medical treatment and social operation in the short term.

Tan Xiaodong, a professor at the School of Public Health, Wuhan University, said that there were more tourists and returnees during the May 1 holiday, and the large turnover of people was superimposed with the decrease in antibody titer in the body, which led to an increase in positive cases. "With the increase in foreign exchanges, the composition of the main epidemic strains in COVID-19 in China has been significantly increased by international influence." Meng Jie, chief physician of the Department of Respiratory and Critical Care Medicine, Xiangya Hospital, Central South University, said that China CDC monitoring showed that XBB series mutants accounted for 97.5% of the imported cases in China in late April, which was basically consistent with the global XBB series mutants, and arcturus was also monitored in China in early April. Relevant research shows that the transmission efficiency of arcturus is 1.27 times higher than that of the original XBB variant, but its pathogenicity has not increased significantly.

2. Does the Infection Summit occur every March to June?

For a long time, according to the virus epidemic situation in some countries, scientists have predicted that the COVID-19 pandemic will eventually enter the seasonal transmission mode like influenza, with the peak of infection occurring every six months. Even with the emergence of strains with higher transmission efficiency, such as Arcturus, the number of infected cases may surge every three to four months, entering a small-scale wave-like repeated epidemic mode.

Experts said that this law has not appeared in China at present, and it is difficult to predict whether it will happen in the future, but there may be "small epidemics" and "small fluctuations", and high-risk places with relatively dense crowds such as schools and hospitals may be greatly affected. Tan Xiaodong said that it has been nearly six months since the last peak of infection in China, and the epidemic situation is still in a sporadic state, and there has not been a large-scale epidemic. Moreover, most of the infected people are mild and rarely have moderate or severe diseases, so it is not necessary to implement socialized and large-scale prevention and control measures.

3. People who are "not positive" are the first to appear positive. Does it mean that these people are more susceptible?

"There is no exact data on whether this infection is more of the’ Shouyang’ or the’ Eryang’. It is more about personal sharing and feelings on social platforms. According to reports, the’ two-yang’ rate in some hospitals has reached 20%~30%, but it is only the proportion of patients, not the whole population. Susceptible population is a relative concept, mostly people who have not been infected before or have low antibody titer in the body. " Tan Xiaodong said that the study predicted that from December 2022 to February 2023, over 82% of the population in China would be infected with COVID-19. The antibodies produced in COVID-19’s body after rehabilitation have a certain protective effect on COVID-19 infection in the following 3~6 months. However, the elderly, people with basic diseases or low immunity have weak immunity. Even if they are infected, the antibody level in the body is low and they are relatively more "susceptible". Meng Jie added that some people who don’t wear masks and have reduced protective measures are also relatively "susceptible".

4. Compared with the previous symptoms, what are the main symptoms of the new wave of infection?

From the perspective of social platforms, some netizens said that after this wave of COVID-19 infection, symptoms such as fever, stuffy nose, cough, sore throat and muscle ache still appeared, but they were consciously lighter than the first symptoms; Some netizens also said that repeated symptoms such as fever, dizziness and fatigue seem to be different from or even worse than the last wave of infection.

Meng Jie said that if infected with COVID-19 once, even if the virus mutates and the antibody titer produced in the body drops, it will help the immune system to quickly identify the virus and make defense. Therefore, in theory, the symptoms of "Er Yang" will be lighter than those of "Shou Yang". However, the symptoms of special groups such as people with poor immunity, people with basic diseases, the elderly and children are not necessarily lighter.

Tan Xiaodong said: "Generally speaking, people with normal immune function have relatively mild symptoms of’ two yang’, and even some people with’ first yang’ have even milder symptoms. This is in line with the epidemiological transmission law of the virus, that is, the later the infection, the lower the pathogenic rate. At present, there have been no reports of serious hospitalization and death caused by arcturus infection in China, and there have been no reports of increased disease severity. "

5. What medical intervention does "Eryang" need?

The data of Guangdong Province, which took the lead in the first wave of COVID-19 infection peak, showed that most re-infected cases had symptoms, but only a few needed medical intervention, and no critical cases were found.

Tan Xiaodong said that ordinary mild patients can heal themselves by resting at home, and take medical intervention if necessary. However, the following groups of people should seek medical treatment as soon as possible after detecting COVID-19’s positive, so as not to develop into severe diseases: 1. People with severe symptoms and long recovery period when they were infected with COVID-19 for the first time, and even people who still have certain symptoms of "growing a new crown", especially those who have had symptoms of white lung; 2. People with serious basic diseases, such as heart failure, emphysema, malignant tumor, immunodeficiency, etc.; 3. Re-infected people with obvious palpitation and chest tightness, and blood oxygen saturation decreased significantly or below 90%.

Meng Jie reminded that the public can make some commonly used drug reserves appropriately. For symptoms such as fever, headache and muscle aches, cold medicines such as acetaminophen tablets can be used; If the nucleic acid test shows that the CT value is low (that is, strong positive), it means that the virus content in the body is high, and antiviral drugs can be used according to the doctor’s advice; When symptoms such as cough appear, choose cough-relieving and phlegm-resolving drugs. It should be noted that drugs have a shelf life and certain environmental requirements for storage. Improper storage is easy to deteriorate. Therefore, people don’t have to hoard drugs excessively, so as to avoid waste and even health risks caused by long-term storage.

6. Do you need to be tested and isolated at home after "Eryang"?

Meng Jie said that if you have symptoms such as cough, fever and sore throat recently, you can use COVID-19 antigen to test yourself. If it is positive, it is suggested to isolate yourself and rest at home, which will help you recover as soon as possible and reduce the risk of cross-infection. Recently, influenza A and respiratory syncytial virus infection have also increased. If the antigen test results are negative, the related symptoms will not be relieved for a long time. It is recommended to go to the hospital for timely diagnosis and treatment.

7. Is it necessary to carry out the fourth national COVID-19 vaccination?

According to a study in the Weekly Report of China CDC, within 3 months and 3~6 months after vaccination with COVID-19 vaccine booster, the effectiveness in preventing Omicron mutant infection was 49% and 37.9% respectively. In addition, within 3 months and 3~6 months after vaccination with COVID-19 vaccine, the effectiveness of preventing Covid-19 infection symptoms was 48.7%~83.2% and 25.9%~69%. Therefore, vaccination is still an effective means to avoid infection, serious illness and death after infection, and the symptoms of "growing a new crown".

At present, the United States, Britain, Israel, Singapore, Denmark and Chile have all implemented the fourth vaccination. The State Council joint prevention and control mechanism conference revealed that China will continue to strengthen the vaccination of high-risk groups and key groups. The "Work Plan for Vaccination in Response to the Recent Infection in Covid-19" issued by the the State Council Joint Prevention and Control Mechanism in April pointed out that the focus of vaccination at this stage is to fill the gap in immune level for different target groups. The target groups are two types: First, people who have been infected and have not completed the first and second injections can be vaccinated with a dose of COVID-19 vaccine after 3 months of infection; Second, people who are not infected and have not completed the established immunization program should complete the vaccination according to the specific time interval requirements, including those who are not infected and have not completed the first and second injections at the age of 3-17; Adults who are not infected and have not completed the third injection; People who are uninfected and at high risk of infection (elderly people over 60 years old, people with serious basic diseases and low immunity) and have not yet completed the fourth injection.

8. COVID-19 can no longer make waves, does it mean that we can not pay attention to it?

In January 2020, the COVID-19 epidemic became a "public health emergency of international concern"; On May 5, 2023, the World Health Organization announced that the COVID-19 epidemic no longer constituted a "public health emergency of international concern". In this regard, Liang Wannian, head of the expert group of the National Health and Wellness Commission’s epidemic response and disposal work leading group, said that at present, the resistance of the population and the health system has reached a relatively balanced state with that of Covid-19, but it does not mean that the COVID-19 epidemic is over, nor does it mean that the epidemic harm is completely gone, let alone that we leave the COVID-19 epidemic unattended.

"Now everyone is generally not so scared about COVID-19, but we should also avoid excessive relaxation. The unknown harm that COVID-19’s repeated infection may bring to health should not be ignored." Meng Jie said that for individuals, there is no need to be overly nervous, which will lead to COVID-19’s influence on physical and mental health and normal life, and they cannot relax their vigilance. No matter the general population or the high-risk population, they should continue to do daily protection, wear masks, wash their hands frequently, pay attention to sneezing and coughing to cover their nose and mouth, and stay away from the crowd after the sun. Everyone is the first person responsible for their own health.