Lancet's paper is detailed! Phase 2 clinical trialshows that the new new crown candidate vaccine developed in China has great potential.

!--:page title"--29(2 ---9) -- A Phase 2 clinical trial in China for the Ad5 vector COVID-19 candidate vaccine in China has shown that the vaccine is safe and induces an immune response, according to a new study.
the results of the study, published online July 20, 2020 in the journal Lancet, are entitled "Eithergenicity and safety of a recombinant adenovirus type-5-vector-vector-dvid-19 vaccine in healthy adults adults 18 years or older: a randomised, double-years, place-phase-with-the-field-research,"
the authors of the paper, Wei Chen, director of the Institute of Bioengineering at the Chinese Academy of Military Medicine, Xing-Huan Wang, president of Zhongnan Hospital at Wuhan University, and Feng Cai-Zhu, deputy director of the Center for Disease Control and Prevention in Jiangsu Province. Professor Zhu Fengcai,
, is also a co-first author of the paper. Another co-author of the
the paper is Xu-Hua Guan, director of the Institute for Infectious Disease Prevention and Control at the Center for Disease Control and Prevention in Hubei Province.
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this randomized clinical trial, designed to assess the safety and immunogenicity of the candidate vaccine, followed the publication of its Phase 1 clinical trial results in May 2020.
compared to Phase 1 clinical trials, the results of this Phase 2 clinical trial provide data on a wider group of participants, including a subgroup of participants over the age of 55, which provides clinical information for the phase 3 clinical application of this candidate vaccine.
, however, the Chinese researchers who led the study noted that it was important to note that no participants had been exposed to the new coronavirus SARS-CoV-2 after vaccination, so the study could not determine whether the candidate vaccine would be effective in preventing SARS-CoV-2 infection. "Compared to Phase 1 clinical trials, Phase 2 clinical trials have added further evidence of safety and immunogenicity in a large number of people," said Professor Feng-Cai Zhu,
.
this is an important step in evaluating this early experimental vaccine, which is currently underway in Phase 3 clinical trials.
" Currently, there are approximately 250 candidate vaccines for SARS-CoV-2 in development worldwide, including mRNA vaccines, replication or non-replicated viral vector vaccines, DNA vaccines, autologous dendritic-based vaccines, and inactivated virus vaccines.
at least 17 vaccines are currently being evaluated in clinical trials.
the candidate vaccine in the 2 clinical trial uses a weakened human common cold virus (adenovirus, which is susceptible to human cells but cannot cause disease) to bring genetic material encoded in SARS-CoV-2 stingproteins into cells.
, these cells then produce a stingprotein and travel to the lymph nodes, where the immune system produces antibodies to recognize the stinging protein and fight the coronavirus.
508 participants participated in Phase 2 clinical trials of the new vaccine.
, 253 received high doses of the vaccine (by 1 x 1011 virus particles/1.0mL), 129 received low-dose vaccinations (by 5 x 1010 virus particles/1.0mL) and 126 received a placebo.
about two-thirds of the participants (309; 61%) were aged 18 to 44, one in four (134; 26%) were between the ages of 45 and 54, and 13% (65) were 55 years of age or older.
immediate adverse reactions were monitored 30 minutes after injection and followed up on any injection site or systemic adverse reactions within 14 and 28 days of vaccination.
record serious adverse events reported by participants throughout the study period.
take blood samples from participants 14 days and 28 days before and after vaccination to measure antibody response.
the clinical trial found that participants in the high-dose group 95% (241/253) and the low-dose group 91% (118/129) had A T-cell or antibody immune response at the 28th day after vaccination.
at the 28th day after vaccination, the high-dose group and the low-dose group had neutralizing antibody reactions in 59% (148/253) and 47% (61/129), respectively, and 96% (244/253) and 97% (125/129) of participants who had combined antibody reactions, respectively.
no increase in antibodies in the participants in the placebo group compared to the baseline.
both doses of the vaccine were able to induce a significant neutralizing antibody response to the live SARS-CoV-2 virus, and the geometric mean titre (geometry mean) of the participants receiving high-dose and low-dose vaccines was 19.5 and 18.3, respectively.
high-dose and low-dose vaccine-induced combination antibody reaction stakes of 656.5 ELISA units and 571 ELISA units, respectively.
T-cell response was also observed in 90% (227/253) participants receiving high-dose vaccinations and 88% (113/129) of participants receiving low-dose vaccinations.
at the 28th day after the injection, the participants in the high-dose group and the low-dose group had an average of 11 spot-forming cells and 10 spots forming cells for every 1 x 105 peripheral blood mononuclear cells, respectively.
the rate of adverse reactions such as fever, fatigue and pain at the injection site was significantly higher in vaccine recipients (72 percent of the high-dose group , 74 percent of the low-dose group, and 37 percent of the placebo group (46/126).
however, most adverse reactions are mild or moderate.
24 people in the high-dose group (9%) had severe (3) adverse reactions over a 28-day period, significantly higher than the participants in the low-dose group or the placebo group (1 in the low-dose group (1%) and 2 in the placebo group (2%). The most common severe reaction
is fever.
!--/ewebeditor--!--webeditor: the !--:page title" -- the researchers noted that the pre-existing immunity and age increases in human adenoviruses, known as vaccine vectors, may partially inhibit the specific immune response to vaccination, especially antibody response.
of the 508 participants, 266 (52%) had higher pre-survival immunity to Ad5 vectors, and 242 (48%) had lower pre-survival immunity to Ad5 vectors.
those with highpre-existing Immunity against Ad5 showed a poorer immune response (binding and neutralizing antibodies levels in people with low pre-existing ad5 immunity were about twice as high as those with highpreion immunity).
the immune response to the Ad5 vector COVID-19 vaccine was generally significantly lower and more tolerant compared to the younger population. "Because older people are at high risk of serious illness or even death associated with COVID-19 infection, they are important targets for the COVID-19 vaccine," said Professor Chen Wei,
.
additional doses may be required to induce a stronger immune response in older populations, but further studies are under way to assess this.
" the researchers point out that the clinical trial was conducted in Wuhan, China, and that baseline immunity represented the situation of Chinese adults at the time, but that the immunization rates in other countries may be different, which should be taken into account.
, the clinical trial followed participants for only 28 days, and there was no persistent data on vaccine-induced immunity in the clinical study.
important, no participants were exposed to THE SARS-CoV-2 virus after vaccination, so the study could not determine the efficacy of the candidate vaccine or any immunological risk associated with the antibodies that were vaccinated when exposed to the virus.
(Bioon.com) References: 1. Feng-Cai Zhu et al. Immunogenicity and safety of a recombinant adenovirus type-5-vectored covid-19 in the health adults aged 18 years or: a da randomised, double-, placebo-controlled, phase 2. Lancet, 2020, doi:10.1016/S0140-6736 (20)31605-6. 2. Chinese phase 2 trial finds vaccine is safe and dats an immune response.