How long can immunity last after a new coronavirus infection?

According to the World Health Organization, as of September 29, 2020, there have been 33,249,563 confirmed cases of neo-crown pneumonia worldwide, and 1,000,040 new crown-infected people have died.
study showed that the body can produce antibodies and T-cells that respond to the new coronavirus after infection, but it is not clear how long these immunity can last, and the results of different teams are not consistent.
A team of researchers detected dynamic changes in the new coronavirus antibody a month after the new coronavirus infection and found that after one month the number of antibodies in patients with mild and severe infections decreased, suggesting that the antibody life against the coronavirus may be short.
study looked at antibody levels in patients four months after a new coronavirus infection and found that neo-coronavirus-specific antibodies rise rapidly after a viral infection and remain at relatively stable levels for four months.
, however, the emergence of a second case of viral infection after the first viral infection has been cured, raising doubts about post-infection immunity and the ability of vaccines to prevent new coronavirus infections.
In order to determine whether antibodies can exist in the human body for a long time after the new coronavirus infection, the National Translational Medical Center of Ruijin Hospital, Shanghai Hematology Research Institute, National Key Laboratory of Medical Genomics, Shanghai Public Health Clinical Center and China Food and Drug Inspection Research Institute have carried out long-term monitoring of new crown infection.
researchers analyzed the expression levels of IgG antibodies in plasma samples from patients 2 weeks to 1 month, 1-2 months and 6-7 months after infection, and found that in plasma samples infected for 6-7 months, anti-neo-coronavirus IgG antibodies decreased from 2 weeks to 1 month and 1-2 months after infection, but remained at a high level.
researchers further analyzed the levels of neo-coronavirus and antibodies in plasma samples 2 weeks to 2 months and 6-7 months after infection and found that there were highly active neo-coronavirus meso-antibodies in all samples, and there was no difference in meso-antibody levels in plasma samples from 2 weeks to 2 months and 6-7 months.
results show that protective neutral antibodies are still present in the human body six months after the new coronavirus infection.
researchers also analyzed the presence of memory T cells for the new coronavirus in the blood of people who recovered after 6-7 months of infection, and found that CD4 and CD8 T cells that responded to the new coronary antigen were present in all test samples.
the virus that caused this year's new crown outbreak is the 614D new coronavirus, but the recent emergence of 614G mutant strains makes the new coronavirus more contagious.
whether human infection with the 614G variant virus can produce sufficient protection has become a high-profile issue.
current vaccines for the new coronavirus are based on the 614D virus, and there are concerns about whether these vaccines will protect the human body from the 614G virus.
to answer these questions, the researchers further analyzed the ability of antibodies taken from plasma samples to mediat 614G analog viruses, or fake viruses.
They found that although most patients were infected with the 614D new coronavirus six months ago, their plasma samples had the same ability to median the 614D and 614G new coronavirus, suggesting that those infected with the 614D virus were also immune to the 614G virus, so it was assumed that the new coronavirus based on 614D should be trustworthy.
the study was published today in Frontiers of Medicine (http://journal.hep.com.cn/fmd/EN/10.1007/s11684-020-0822-5), co-author of the study. Dr. Tan Yun, Dr. Liu Feng, Dr. Xu Xiaoguang, Dr. Ling Yun, Dr. Zhu Zhaoqin, Dr. Guo Mingquan, Dr. Lin Yixuan and Huang Weijin of the China Food and Drug Inspection Research Institute, affiliated with the Ruijin Hospital of Jiaozhou University School of Medicine.
co-authors are Professor Chen Saixuan of the National Translational Medicine Center of Ruijin Hospital, affiliated with Shanghai Jiaoxuan University School of Medicine, Shanghai Institute of Hematology, National Key Laboratory of Medical Genomics, and Professor Lu Hongzhou of Shanghai Public Health Clinical Center.
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