"The Lancet" single-dose Chinese Ad5-NCOV COVID-19 vaccine is safe and effective in Phase III clinical trials

• According to the analysis of a phase III randomized controlled trial, the Ad5-nCoV vaccine developed in China is effective 57.

  
  

• There are no reports of serious vaccine-related adverse events.

  
  

• Research is currently underway to determine the long-term safety and effectiveness of the vaccine, as well as its effectiveness against delta, omicron, and other worrying variants

  
  

According to a phase three randomized controlled trial published in the journal The Lancet, one dose of Ad5-nCoV (Convidecia) is a COVID-19 vaccine developed in China.

The report showed that Ad5-nCoV is safe, no serious vaccine-related adverse events or deaths were reported among trial participants, and the vaccine induced a strong antibody response

Ad5-nCoV is a single-dose viral vector vaccine that can be stored between 2°C and 8°C

"Our research shows that a single dose of Ad5-nCoV is very effective for serious diseases and may help relieve the tremendous pressure COVID-19 has placed on health systems around the world, because it can prevent people from getting serious illnesses or needing to be hospitalized

The study is still ongoing.

On January 15, 2021, after reaching the protocol threshold of 150 cases of laboratory-confirmed (RT-PCR positive) symptomatic COVID-19 28 days after the injection, the researchers conducted an efficacy analysis.

At 28 days after vaccination, the curative effect on severe illness was 91.

According to phase 1 and phase 2 trials, Ad5-nCoV is well tolerated and produces high levels of anti-rbd and neutralizing antibodies

Most adverse events, including pain at the injection site, headache, drowsiness, and general muscle pain, were mild to moderate and occurred within 7 days after the injection

The authors warn that the efficacy analysis was performed on samples collected on or before January 15, 2021, and therefore does not include analysis of more recent delta and omicron variants

Dr.

The authors pointed out that other secondary results will be analyzed, including the efficacy of asymptomatic infections and the efficacy of PCR-negative and seroconversion-positive cases

Other ongoing studies are exploring the relative efficacy of single-dose and double-dose Ad5-nCoV

The author points out some limitations of further research
.
Although this study was conducted in five countries, most of the study participants in this analysis were from Pakistan (16950 participants) and Mexico (13559 participants); this was mainly because the trial was conducted in September 2020.
It was first launched in Pakistan on November 22, and then launched in Mexico on November 6, 2020
.
People with unstable physical conditions, pregnant people, and children were excluded from the study
.
Women and the elderly are also under-represented
.
Although the researchers actively searched for cases through weekly calls and text messages, the symptoms and signs were self-reported (although confirmed through personal research visits), so not all positive cases were included
.
Further research is currently underway to determine the long-term durability of Ad5-nCoV and the effectiveness of the variants concerned
.

Dr.
Richard Kennedy of the Mayo Clinic in the United States did not participate in the study.
He wrote in relevant comments: "Despite the remarkable achievements in the development and production of the SARS-CoV-2 vaccine, there are still a large part of the world.
Access to vaccines is still limited
.
In some parts of the world, indecision is also an obstacle to achieving high vaccination rates
.
In addition to these challenges, the immunity of the SARS-CoV-2 vaccine is weakening, and it can evade immune changes to varying degrees.
The body continues to appear
.
Therefore, there is an urgent need to continue to develop, test and use more vaccines
.
This research provides important data support for the continued use of another adenovirus vector vaccine
.
Continued monitoring of this research population will be necessary to Answer the current questions about the decline in immunity, the duration of protection, the need for enhanced vaccination, and the ability to protect against new variants including Omega
.
"

References: "Final efficacy analysis, mid-term safety analysis and immunogenicity of single-dose recombinant novel coronavirus vaccine (adenovirus type 5 vector) for adults 18 years and older: an international, multi-center, randomized, double-blind, and comfort Contrast Phase 3 Trial", December 23, 2021, "The Lancet"
.
DOI: 10.
1016 / s0140-6736 (21) 02753-7

This research was funded by CanSino Biological Products Co.
, Ltd.
and Beijing Institute of Biotechnology
.
A complete list of researchers and institutions is provided in the paper
.