Experiments show that 3 months after the booster shot of the inactivated vaccine, the body still has a certain amount of neutralizing antibodies against Omicron, and those who break through the infection form a strong humoral immune barrier against Omicron. It is of great significance for the development of neutralizing antibody drugs against the Omicron strain and future new mutant strains.

  Today, mankind has been fighting the new coronavirus for more than two years.

There are high hopes for accelerating the development and application of vaccines, increasing the vaccination rate, and building a herd immunity barrier.

However, with the emergence of new coronavirus variants one after another, the effectiveness of vaccines and their update iterations have become important issues that the scientific community must address.

  Recently, a joint research team carried out a retrospective study based on the clinical data of 430 cases of Omicron BA.1 infection in Tianjin, which was first published in Tianjin. The severity of the disease in Mikron-infected patients can be effectively shortened, and the true virus neutralization experiment has proved the continued effectiveness of the inactivated vaccine against the Mikron variant.

This is also the first reported scientific evaluation of the protection of inactivated vaccines against new coronary pneumonia caused by Omicron mutants in the real world, and the results of its true virus neutralization experiments are of great value for the development of neutralizing antibody drugs.

  Strengthening the protection of middle-aged and elderly people can reduce the damage to public health caused by the epidemic

  The joint research team consists of the First Affiliated Central Hospital of Nankai University, the Biomedical Frontier Innovation Center of Peking University, the Institute of Immunology of Nankai University, the Tianjin Institute of Hepatobiliary Diseases, the Department of Immunology of the Institute of Basic Medicine, Chinese Academy of Medical Sciences, and Beijing You'an Hospital. , and researchers from the State Key Laboratory of Medical Immunology, Naval Medical University of the Chinese People's Liberation Army.

From January 8 to February 7, 2022, they conducted a series of statistical analyses by combining clinical data and new crown vaccination information with 430 patients with new coronary pneumonia diagnosed in Tianjin from January 8 to February 7, 2022.

  The 430 patients with 2019-nCoV in this study were discharged from Tianjin Haihe Hospital and were admitted to the Shuixi District of the First Affiliated Central Hospital of Nankai University for isolation and rehabilitation treatment.

Among them, 316 (73.5%) were adult patients, and the median age (median age of infected persons) was 47 years; 114 (26.5%) were minor patients, and the median age was 10 years.

The severity of the disease was mainly mild (47.7%) and common (50.2%), with 2 severe cases (0.5%) and 7 asymptomatic infections (1.6%), with no deaths.

The researchers found that increased age was an independent risk factor for disease severity in Omicron infection.

87.8% of minor patients had only mild symptoms or no symptoms, while the proportion of mild or asymptomatic infections among adults was only 35.4%.

Minor infected people do not need ICU treatment, and there are fewer re-positives after the nucleic acid turns negative.

  "Clinical data show that the higher the age, the more severe the symptoms after infection, which suggests that we should focus on strengthening the epidemic protection of the middle-aged and elderly people to reduce the damage to public health." Zheng Hong, deputy director of the First Affiliated Central Hospital of Nankai University, said.

  The efficacy of the new crown inactivated vaccine that can induce inflammation and shorten the course of disease has been verified

  Of these 430 infections, 341 (79.3%) received inactivated vaccine, 49 (11.4%) received adenovirus vector vaccine, 2 (0.5%) received recombinant protein subunit vaccine, and 38 (8.8%) have not received any kind of new crown vaccine.

The research team conducted a scientific analysis on the issue of vaccine effectiveness, which is of the greatest concern to the public.

  Statistics show that the whole course of inactivated vaccine and booster injections in adults can significantly reduce the severity of clinical symptoms, reduce the probability of ICU admission, reduce the nucleic acid recovery rate, and shorten the hospitalization and recovery time (1-2 days on average).

The researchers analyzed the laboratory test results at the initial stage of recovery after the patient's nucleic acid turned negative and found that the infected patients who received the booster shot of the inactivated vaccine entered the inflammation subsidence period faster, and their systemic immune inflammatory index, C-reactive protein levels and lymphocyte ratios were relatively lower.

  "We believe that these laboratory indicators indicate lower levels of inflammation, indicating that 3 doses of inactivated vaccine may shorten the course of COVID-19 by inducing inflammatory outcomes," said Jiang Wentao, deputy dean of the First Affiliated Central Hospital of Nankai University. .

  In order to further verify the protective efficacy of the new crown inactivated vaccine, the research team measured the plasma neutralizing antibody titers of Omicron infection recovered patients through the new crown virus true virus neutralization experiment.

The experimental results show that the geometric mean of the 50% neutralizing titers (NT50, the antibody titer that protects 50% of host cells from being infected by the virus) against the original strain in infected individuals who received 3 doses of inactivated vaccine is the difference between beta and 4.2 times and 8.4 times that of Omicron NT50.

Plasma neutralization titers in normal patients were higher than those in mild patients.

Compared with healthy people who received 3 doses of inactivated vaccine, the neutralizing titers to Omicron were significantly increased in breakthrough patients (people who became infected with 2019-nCoV after completing 2019-nCoV vaccination) who received 3 doses of inactivated vaccine ( 8.7-fold), and there was also cross-immunity to beta (4.5-fold) and the original strain (2.2-fold).

  "Experiments show that after 3 months of inactivated vaccine booster injection, there are still certain neutralizing antibodies against Omicron in the body, and those who break through the infection form a strong humoral immune barrier against Omicron. This is of great significance for the development of neutralizing antibody drugs against the Omicron strain and future new variants," said Chen Xiaosu, a postdoctoral fellow at the Institute of Immunology, Nankai University.

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