echemi logo
Product
  • Product
  • Supplier
  • Inquiry
    Home > Active Ingredient News > Drugs Articles > The first case of secondary infection in a new crown patient, is the vaccine still useful?

    The first case of secondary infection in a new crown patient, is the vaccine still useful?

    • Last Update: 2020-09-29
    • Source: Internet
    • Author: User
    Search more information of high quality chemicals, good prices and reliable suppliers, visit www.echemi.com
    Antibody maintenance time is short, but does not mean that the immune vanishing vaccine is developed on the premise of understanding the virus invasion of the human body mechanism - mainly the surface of the virus S protein, binding to the human cell aCE2 subject, into the human cell began to replicate.
    as an RNA virus, the new coronavirus consists mainly of 4 structural proteins and 1 unstructy protein.
    these proteins produce antibodies in the body, but not all of them are protective - only antibodies that bind to the S protein on the surface of the virus can protect them.
    S protein antibody is also known as the nalorem antibody.
    current vaccine research and development, mainly to induce the human body to produce S protein antibodies, replace human cells ACE2 bind to S protein in advance, to prevent the virus into the body.
    addition, when the human body is infected with the new coronavirus, different antibody subsypes appear in the body: the first IgM antibody appears, followed by the IgG antibody.
    that IgM antibodies take about 5-7 days to produce after a new coronavirus invades, and IgG antibodies take about 10-15 days to produce.
    current vaccine research and development, but also mainly to induce the human body to produce S protein antibodies, stimulate the IgG sub-type.
    , several studies have shown that the duration of new coronary antibodies is very limited.
    A follow-up study of more than 90 patients in the UK showed that new coronary and antibody levels peaked about five weeks after symptoms and then began to decay;
    3 months after infection, antibody levels decay sharply, even to zero.
    And studies from Chongqing Medical University have also shown that a large proportion of individuals recovering from neo-coronavirus infection have IgG and meso-antibody levels that decline within 2-3 months of infection: 81% of asymptomatic infected people have antibodies in their bodies over an eight-week period. The proportion of antibodies decreased by 62% in the symptomatic population, and in less than 60 days, 40% of asymptomatically infected people had antibodies reduced to erratic levels, while 12.9% of those diagnosed with symptoms decreased to erratic levels.
    means that the new coronary antibodies will disappear quickly and the protection cycle will be short - and it's not hard to see why hong Kong patients can get a second infection when they recover.
    , a 33-year-old man was diagnosed in March, discharged from hospital in April, and re-diagnosed after testing positive for nucleic acid when he entered Hong Kong in August, according to media reports.
    researchers said there were 24 differences in the genetic sequencing of the second strain of infection in the patient compared to the first, and no antibodies had been detected on the second hospitalization.
    antibodies disappear, is the individual as if he had not been infected, completely unfamiliar with the new coronavirus? This is not entirely the case.
    antibodies disappear, they don't mean immunity is gone.
    Akiko Iwasaki, a professor of immunology at Yale University, told the media that while the new coronavirus has significantly reduced titration, when the new coronavirus invades again, memory T and B cells in the body can quickly identify the invading virus and stimulate antibodies and cellular immune responses more quickly and effectively.
    and this time, hong Kong patients after the secondary infection, there are also symptoms of milder and IgG antibody production faster and other positive phenomena, perhaps also shows that "understanding" the new coronavirus immune system, can play a protective role.
    there has been only one case of secondary infection, the specific mystery has yet to be further studied.
    "if the news of re-infection is true and develops in the future, there will be a significant impact on vaccine protection and vaccination intervals."
    Wenhong, director of the infection department at Huashan Hospital, wrote on his microblog that if a similar situation did not occur again, the situation would remain at the news level, not the academic level.
    more than 10 research and development paths to increase the probability of success At present, the new crown vaccine research and development progress very fast, and the technical route is complete, research and development varieties.
    In general, there are three main categories: first, classical technology (inactivated vaccine), second, gene recombinant technology, mainly recombinant protein vaccine (sub-units, virus particles), and third, new technologies, including viral vector vaccine (replicated, non-replicated), nucleic acid vaccine (DNA-mRNA) and so on.
    Among them, inactivated vaccine technology is the most classic, the most rapid progress, especially in China has three teams have entered clinical phase III trials, but in addition to the production of neutral antibodies in the body, but also may produce non-neutral antibodies, resulting in vaccine antibody-dependent infection enhancement (ADE) effect - that is, after vaccination, if re-infected with the disease, but will promote viral infection.
    issue is also one of the most important focuses of research and development.
    Recently, the Drug Audit Center of the State Drug Administration issued five documents, such as the Technical Guidelines for the Development of Vaccines for the Prevention of New Coronavirus (Trial), among which the Guidelines for clinical evaluation of vaccines for the prevention of new coronavirus (Trial) have given specific evaluation criteria for the safety, effectiveity and data of overseas clinical trials.
    the safety of vaccines, the ADE phenomenon mentioned above is concerned, requiring systematic testing of the relevant conditions, timely detection and tracking of possible aggravation of infection, etc.
    effectiveness, a minimum protection rate of 50 per cent is required, and the protection time requires that the vaccine preferably provide protection for one year or more and at least six months.
    , the evaluation of vaccine effectiveness must not bypass the problem of the disappearance of new coronary antibodies.
    above, the disappearance of new coronary antibodies does not mean the disappearance of immunity, and the evaluation of the effectiveness of the new coronary vaccine should perhaps include changes such as memory T-cells and B-cells.
    "in the past, antibodies have been used to evaluate the effectiveness of the vaccine, whether the new crown vaccine will use this classic route, still need to be studied in depth."
    , chief expert and chief physician of the Immunization Program of the China Center for Disease Control and Prevention, said.
    " at present, a number of candidate vaccines have entered the clinical phase III, estimated that the results, the protection rate should be around 60-70%.
    , vice president of the China Vaccine Industry Association, told the health community.
    a new infectious disease, its pathogen, clinical, epidemiology, technology and so on are in the understanding.
    , it's not clear which technical route will be adopted and who will reach the finish line.
    " and multiple technical routes are studied in parallel, allowing us to respond to outbreaks with more options and greater odds.
    ," Wang Huaqing said.
    .
    This article is an English version of an article which is originally in the Chinese language on echemi.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to service@echemi.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

    Contact Us

    The source of this page with content of products and services is from Internet, which doesn't represent ECHEMI's opinion. If you have any queries, please write to service@echemi.com. It will be replied within 5 days.

    Moreover, if you find any instances of plagiarism from the page, please send email to service@echemi.com with relevant evidence.