Days after US drugmaker Moderna announced Phase one trial of its COVID-19 vaccine has shown positive results, researchers on Friday reported that a vaccine developed in China appears to be safe and may protect people from the deadly virus.
According to a report in The New York Times citing early-stage trial, published in online journal Lancet, those who received a single dose of the vaccine produced certain immune cells, called T cells, within two weeks, while the antibodies needed for immunity peaked at 28 days after the inoculation.
The trial was conducted by researchers at several laboratories and included 108 participants aged 18 to 60.The trial was conducted by researchers at several laboratories and included 108 participants aged 18-60. According to the latest data from Johns Hopkins University, the number of coronavirus cases worldwide has gone up to 5,209,266.
According to the NYT report, results of just one other human vaccine trial, which has now entered mid-stage human trials have been published in a scientific journal. The vaccine reported on Friday was made with a virus, called Ad5, modified to carry genetic instructions into a human cell. The cell begins making a coronavirus protein; the immune system learns to recognize the protein and attack it, in theory preventing the coronavirus from ever gaining a foothold.
In these people, “their immune systems will essentially rear up and blunt the effect of the vaccine,” said Dr. Kirsten Lyke, a vaccinologist at the University of Maryland who is leading another coronavirus vaccine trial.
Researchers in China did find that people who had Ad5 antibodies were less likely to develop a strong immune response to the vaccine.”That may limit the use of this vaccine,” said Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine.
“If you’re comparing vaccines, the adenovirus ones so far seem to be on the lower end of the spectrum,” he added.However, the results of this vaccine are based on data from a short period, and it is unclear how long its protection might last.
What is Ad5-nCoV vaccine and how does it work against COVID-19?
Ad5-nCoV, was the first vaccine for COVID-19 to enter clinical trial in China. It uses a weakened common cold virus known as an adenovirus, which infects human cells but doesn’t cause disease, to deliver a fragment of genetic material from SARS-CoV-2. The experimental vaccine is built upon CanSinoBIO’s adenovirus-based viral vector vaccine technology platform. Results from preclinical animal studies of the vaccine showed that ‘Ad5-nCoV’ can induce a strong immune response in animal models, demonstrating a good safety profile.
In the phase 1 trial of Ad5-nCoV, participants were administered either a low, middle or high dose of the vaccine. Three weeks after vaccinations, the researchers observed that subjects in all three groups developed binding antibodies – the immune system’s frontline defenders.
Test results also showed about half of the participants in the low- and middle- dose groups and three-quarters of participants in the high-dose group developed ‘neutralising antibodies’, capable of destroying live SARS-CoV-2 virus in a test tube.
The study also reported that those who received a single dose of the vaccine produced certain T-cell responses.
According to the study, the most common side effects of the vaccine were mild fever, headache, mild pain at the site of injection, fatigue and muscle pain. The researchers observed that nine participants developed a fever of more than 101 degrees Fahrenheit (38.5 degrees Celsius). Also, one participant in the high dose group developed a high fever along with shortness of breath, fatigue, and muscle pain. The effects occurred within 24 hours post-vaccination, and persisted for no more than 48 hours.
In conclusion, the researchers noted that the Ad5 vectored COVID-19 vaccine is tolerable and immunogenic in healthy adults. The vaccine produced specific humoral responses against SARS-CoV-2 peaked at day 28 post-vaccination. However, they said there is potential for further investigation of the Ad5-nCoV vaccine for the control of the COVID-19 pandemic.
The researchers have now begun a larger, phase 2 clinical trial in China, which will provide more information on the safety and immunogenicity of the Ad5 vectored COVID-19 vaccine. Currently, more than 100 vaccines are under development worldwide with at least 8 of them in the process of human trials.