Three vaccine candidates race to combat SARS-CoV-2

As the coronavirus disease (COVID-19) ravages across the globe, scientists are racing to develop an effective vaccine to combat the viral infection. Caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the disease has infected nearly 9 million people.

Now, three candidate vaccines show promising preliminary results from tests, sparking hope to have an effective vaccine to combat the deadly vaccine soon.

Image Credit: Fusion Medical Animation
Image Credit: Fusion Medical Animation

Chinese vaccine enters phase II trial

So far, more than a dozen vaccines are in the different stages of human trials across the globe. Many countries and scientists are accelerating the testing of these vaccines to find an effective one to protect people against the coronavirus pandemic, which has spread to 188 countries and territories.

An inactivated COVID-19 vaccine candidate developed by the Institute of Medical Biology under the Chinese Academy of Sciences has progressed to second phase human trials.

The phase II trial aims to evaluate the immunogenicity, effectiveness, and safety of the vaccine in humans. The trial will be held in the southwestern province of Yunnan.

The experimental shot is among six possible vaccines scientists are testing on humans in the country. Following an on-going phase I study that has recruited an estimated 200 participants. The phase II trial will determine the vaccine’s appropriate dosage and if the vaccine can safely stimulate immune responses in healthy people.

Australia’s promising vaccine

Another vaccine has been developed in Australia. GlaxoSmithKline, a British pharmaceutical group, has started clinical trials in Western Australia. The pharmaceutical giant partnered with Clover Pharmaceuticals, a biotech company based in China. The vaccine, S-Trimer vaccine (SCB-2019) in partnership with GSK’s pandemic adjuvant system, entered human trials after promising results in pre-clinical tests done in animals. The phase I study has begun in Perth, and the results are expected in August. The more significant efficacy test, phase II trial stage, is expected to commence later in the year.

The Glaxo collaboration with Clover relies on the company’s adjuvant system, a booster designed to improve and boost the body’s immune response. The company said it could reduce the amount of vaccine required per dose, allowing more people to be immunized and generate longer-lasting immunity.

“Our deliberate approach is to combine our proven pandemic adjuvant technology with protein-based COVID-19 vaccine candidates from several collaborators. We believe this holds the promise to produce vaccines at scale, potentially benefiting billions of people,” Thomas Breuer, Chief Medical Officer, GSK Vaccines, said.

“We are encouraged by the pre-clinical data of this adjuvanted COVID-19 vaccine candidate from Clover and look forward to reviewing the data from this first trial. If this trial is successful, we hope to be in a position to move into more advanced trials later in the year,” he added.

Israel’s COVID-19 vaccine’s animal testing

The recombinant VSV-∆G-spike vaccine developed at the Israel Institute for Biological Research provided protection against SARS-CoV-2 in animal studies.

In a study published on the preprint server BioRxiv*, the vaccine proved effective against COVID-19 in Syrian golden hamsters. The vaccine has resulted in the rapid and potent induction of neutralizing antibodies against the novel coronavirus.

In the study, two groups of hamsters were used. One group received the vaccine before being infected with SARS-CoV-2, while the other group was not immunized. The animals that received a single dose of the vaccine did not lose weight. Their lungs showed only minor lung damage and had no viral load. On the other hand, the control group had extensive lung tissue damage and high viral loads.

“Importantly, single-dose vaccination was able to protect hamsters against SARS-CoV-2 challenge, as demonstrated by the abrogation of body weight loss of the immunized hamsters compared to unvaccinated hamsters,” the researchers wrote in the paper.

“Furthermore, whereas lungs of infected hamsters displayed extensive tissue damage and high viral titers, immunized hamsters’ lungs showed only minor lung pathology, and no viral load. Taken together, we suggest recombinant VSV-∆G-spike as a safe, efficacious, and protective vaccine against SARS-CoV-2 infection,” they concluded.

The coronavirus disease has now killed more than 470,000 people worldwide. The United States reports the highest number of cases, with more than 2.30 million people infected. Brazil’s cases skyrocketed over the past weeks and have now topped 1.1 million infections, with at least 51,000 deaths. Meanwhile, Russia, India, and the United Kingdom have reported a high number of cases, with at least 591,000, 425,000, and 306,000 cases, respectively.

*Important Notice

bioRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Journal reference:
Angela Betsaida B. Laguipo

Written by

Angela Betsaida B. Laguipo

Angela is a nurse by profession and a writer by heart. She graduated with honors (Cum Laude) for her Bachelor of Nursing degree at the University of Baguio, Philippines. She is currently completing her Master's Degree where she specialized in Maternal and Child Nursing and worked as a clinical instructor and educator in the School of Nursing at the University of Baguio.


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