New vaccine offers hope in the fight against coronavirus

Clinical trials are often used by scientists to test new methods of diagnosing, treating or preventing diseases. FILE PHOTO | NMG 

By SARAH OOKO
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To effectively tackle the coronavirus disease, which has caused havoc to nations world over by crippling economies and health systems, scientists have been working round the clock to develop a
suitable vaccine for the condition.

In this journey, many of the potential vaccines have not made it that far. But there is finally light at the end of the tunnel, based on new findings published in the “Lancet” journal.

The research, which focused on the first Covid-19 vaccine to reach phase one clinical trials, found that the vaccine was safe and well tolerated in human beings.

Most importantly, the researchers discovered that the vaccine was able to generate an immune response against the virus that causes Covid-19, which is known as SARS-CoV-2.

Clinical trials are often used by scientists to test new methods of diagnosing, treating or preventing diseases (such as Covid-19).

The goal is to determine whether a novel product is both safe and effective in human beings.

Before people are exposed to a potential vaccine in clinical trials, it is first tested in small samples of human cells (not people) or animals in laboratories.

During this period, the researchers assess the effects of a vaccine to find out if it is toxic or whether it has the potential of harming human beings.

If the results at this stage are promising, the vaccine is allowed to move to Phase One trials. It is at this stage that the vaccine is tested in people for the first time.

Previous potential Covid-19 vaccines did not make it past the preliminary research stages and could not therefore be tested in people.

Yet, the creation of an effective vaccine is seen as the long-term solution to controlling the pandemic.

In this regard, the new vaccine analysed in the “Lancet” study – known as the adenovirus type 5 vectored Covid-19 (Ad5-nCoV) - represents a milestone in the search for a vaccine against the coronavirus disease that has no cure.

“The new vaccine evaluated in this trial is the first to be tested in humans. This represents an important milestone,” stated the researchers.

Indeed, the results of the study demonstrated that a single dose of the vaccine produces antibodies against the virus that causes Covid-19 in 14 days.

This makes it a potential vaccine candidate for further investigation,” said Prof Wei Chen, the lead author of the study from the Beijing Institute of Biotechnology in China.

He however noted that the results of the study should be interpreted cautiously as further studies are still required before the vaccine can be approved.

“The challenges in the development of a Covid-19 vaccine are unprecedented, and the ability to trigger these immune responses does not necessarily indicate that the vaccine will protect humans from Covid-19.

This result shows a promising vision for the development of Covid-19 vaccines, but we are still a long way from this vaccine being available to all."

The research was conducted among 108 healthy adults between the ages of 18 and 60 years who did not have Covid-19.

Volunteers participating in the study were enrolled from one site in Wuhan, China. They were divided into three groups that received a low, medium or high dose of the candidate vaccine.

The results of the study, following blood tests conducted at regular intervals among volunteers, showed that the vaccine was able to stimulate the body’s immune system against the SARS-CoV-2 virus that causes the Covid-19 disease. Most people developed a type of antibody that can attach to the virus, though not necessarily destroy it. Some also developed the so-called neutralising antibodies, which can block the virus.

The concentration of neutralising antibodies, which researchers believe is important in acquiring protection against the virus, appeared to increase with dose strength.

Indeed, within 28 days, 75 percent of patients that received a high dose of the vaccine were found to have neutralising antibodies compared to 50 percent of the volunteers that got a low or moderate dose of the vaccine.

The vaccine candidate was also well tolerated at all doses, with no serious adverse effects reported within 28 days of vaccination.

The few effects that were reported were mild and moderate. They included pain at the injection point, fever, headache and muscle pain.

One participant that had been given the higher dose vaccine reported severe fever along with severe symptoms of fatigue, shortness of breath, and muscle pain. However, these adverse reactions persisted for less than 48 hours.

With the success of the phase one trial, the researchers have already initiated a Phase Two trial in Wuhan to further test the safety and efficacy of the vaccine.

This research will determine whether the results of the phase one trial can be replicated in a larger group of people. It will involve 500 healthy adult volunteers, including participants over 60 years old, who are an important target population for the vaccine.