Initial results suggest that the vaccine is safe and elicits an immune response.
Researchers write this in the journal The Lancet . They base their cautious conclusions on a clinical study involving more than 500 people.
About the vaccine
The vaccine in question consists of a weakened cold virus that is used to deposit genetic material of the coronavirus in our cells. That genetic material describes how to make the distinctive spike protein – found on the outside of SARS-CoV-2. As soon as this genetic code arrives at our cells, they will use the building instructions to produce the protein, after which the immune system is confronted with it and can start making antibodies against it. For example, the immune system is already put in place in case the vaccinated person actually comes into contact with the coronavirus at a later stage. It is hoped that the vaccine can ensure that the immune system clears the virus before it can infect our cells.
And now researchers have tested the vaccine. 508 people participated in the experiment. 253 of the subjects received a high dose of the vaccine. 129 subjects were administered a low dose. And 126 subjects received a placebo. 28 days after vaccination, 95 percent of high-dose subjects and 91 percent of low-dose subjects had an immune response noted: these subjects had antibodies or T cells (white blood cells called SARS -CoV-2 can attack) created.
In addition, clinical research suggests that the vaccine can be safely administered. Most subjects experienced mild side effects at most. In the group receiving a larger dose of the vaccine, some of the subjects developed a fever, but it persisted briefly and disappeared without medication or further treatment, the researchers write.
The test results of the vaccine developed and tested in China closely follow that of a vaccine developed at the University of Oxford. That vaccine works in much the same way as that of the Chinese and also delivers genetic material of SARS-CoV-2 into the body with the help of another virus. This British vaccine was also found to generate a powerful immune response and to stimulate the production of (neutralizing) antibodies and T cells . “Both studies have a similar approach,” said Professor Brian Oliver, of the University of Technology Sydney, an expert in respiratory infections and not involved in the development of the vaccines. “They have taken a generally harmless cold virus and adapted it to produce the proteins of the SARS-CoV-2 virus. That may sound terrifying, but it’s a very common way to make a vaccine. ” And so the vaccine seems to work in both cases. “Both studies are positive: vaccinated people made antibodies against SARS-CoV-2.” And that’s good news. “These studies do not show that vaccination prevents COVID-19, but reveal that vaccinated people produce antibodies against the virus, and therefore it is plausible that a vaccination limits the symptoms of a SARS-CoV-2 infection, just like the flu shot that ( for flu infections, ed.). ”
But we’re not there yet, says Rob Grenfell, of the Commonwealth Scientific and Industrial Research Organization (CSIRO), an Australian organization that recently tested the corona vaccine developed at Oxford on animals. “While these are hopeful results, we still have a long way to go before a suitable vaccine is within reach. We have yet to wait for the third phase of clinical research, in which the effectiveness and safety of the candidate vaccines will be further investigated (…) It is not clear whether the candidate vaccines work and can be safely distributed to a larger group of people before these large-scale clinical studies have been carried out and it has been proven that the vaccinated group is protected. ”
The third phase of clinical research Grenfell refers to is usually the most time consuming phase. In this part of the research, they want to prove that the vaccine can actually prevent people from becoming infected with the virus. A large group of people must first be collected for the study, half of whom will receive a placebo and the other half the corona vaccine. You then have to wait until a large proportion of the subjects in both groups have come into contact with the coronavirus to demonstrate that infections among the vaccinated group are not or at least much less common. You can imagine that it takes a lot of time. There is a possibility of speeding up this third phase by deliberately exposing people to the coronavirus after vaccination (with the corona vaccine or the placebo). Last week More than 100 scientists argued that this approach should be used to obtain a vaccine as quickly as possible and to save as many human lives as possible. It is still unclear whether that will actually happen.
The vaccine developers will continue as usual. For example, the vaccine developed at the University of Oxford will soon be tested on more than 10,000 British people. Large-scale studies are also underway in the US, Brazil and South Africa. And the Chinese also hope to start the third phase of clinical research soon.
During this third and final phase of clinical research, it should not only be clear whether the vaccine can prevent SARS-CoV-2 from infecting people. The safety of the vaccine is also reviewed. In addition, it must be clear what the optimal dose is. In the meantime, it is also important to monitor subjects vaccinated in the first and second phases of the study. For example, it should be made clear how long the immune response that the vaccine elicits lasts.
Many more candidate
vaccines In addition to the vaccines mentioned in this article, which are being developed in China and Great Britain, 164 vaccines are still being developed, according to the World Health Organization . 24 candidate vaccines are already being tested on humans. Most are still in the initial phase of clinical research, where a vaccine is being tested for the first time in (a small group of) people. However, there are a few vaccines that are already a lot further and are (almost) entering the third and final phase of clinical research. This concerns the vaccine developed in Oxford, but also the 1273 mRNA developed by the Americans and two Chinese vaccines, including the one that is central to this article.