Researchers released preliminary findings of two vaccine candidates against COVID-19, the disease caused by the novel coronavirus, on July 20.
A vaccine candidate developed by the University of Oxford appeared safe and induced strong immune response within the body, scientists announced on July 20. This came after phase-I of "promising" human trials against COVID-19, the disease caused by the SARS-Cov2 virus.
Another COVID-19 vaccine developed by CanSino Biologics Inc and China’s military research unit has also shown to be safe and triggered immune response in most recipients, according to researchers.
Doses of the vaccine were given to 1,077 healthy adults aged between 18 and 55 in five United Kingdom hospitals in April and May as part of the phase-I clinical trial and results, published in the ‘Lancet' medical journal.
The vaccine candidate, called ChAdOx1 nCoV-19, showed a significant increase in T-cell responses targeting SARS-CoV-2 spike protein in 43 of the participants. The response peaked after 14 days, as per the journal.
The results show they induced strong antibody and T-cell immune responses for up to 56 days after they were given. T-cells are crucial for maintaining protection against the virus for years.
The findings are seen as promising, but experts feel it is too soon to know if this is enough to offer protection as larger trials get underway.
CanSino’s vaccine is yet to begin its large-scale clinical trials. This stage is required to check how it performs to prevent people from getting infected. However, it has received the approval for usage in the Chinese military.
The mid-stage result supports testing of the vaccine candidate in a large trial.
It uses a virus called ‘adenovirus’ to carry genetic material from the novel coronavirus’ protein into the human body. This method has also been used by researchers at Oxford University and its partner AstraZeneca for their vaccine candidate.
Oxford University’s ChAdOx1 nCoV-19 and CanSino’s candidate Ad5-nCOV, are among a handful of vaccines that have shown promise in the clinical testing stage. These are gearing up for late-stage trials.
There are other projects involving Moderna Inc, BioNTech SE and Inovio Pharmaceuticals Inc.
On July 14, US researchers reported that Moderna’s experimental COVID-19 vaccine had shown it was safe and provoked immune responses in all 45 healthy volunteers in an ongoing early-stage study.
Moderna’s shot, mRNA-1273, uses ribonucleic acid (RNA) - a chemical messenger that contains instructions for making proteins. When injected into people, the vaccine instructs cells to make proteins that mimic the outer surface of the coronavirus, which the body recognises as a foreign invader, and mounts an immune response against.
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No study volunteers experienced a serious side effect, but more than half reported mild or moderate reactions such as fatigue, headache, chills, muscle aches or pain at the injection site.
The company was the first to start human testing of a vaccine for the novel coronavirus on March 16, some 66 days after the genetic sequence of the virus was released.
German biotech firm BioNTech and United States drug maker Pfizer also reported additional data on July 20, from their experimental COVID-19 vaccine that showed it was safe and induced an immune response in patients.
The companies said the data also demonstrated an induction of high level of T-cell responses against the novel coronavirus.
Over 150 possible vaccines are currently being developed and tested around the world. Of these, 23 candidates in human clinical trials, including those mentioned above.
Experts suggest that a safe and effective vaccine could take 12-18 months to develop.(With inputs from agencies)