- The CoronaVac vaccine has been granted emergency permission in 37 nations by officials.
- According to preliminary results from a phase 3 trial conducted in Turkey, CoronaVac provides 83.5 percent protection against symptomatic COVID-19 infection.
- CoronaVac, according to the findings, provides 100 percent protection against being admitted to the hospital due to COVID-19.
- However, according to a more recent investigation that included more data, both of these figures have been drastically reduced.
On the basis of intermediate phase 3 trial data, scientists reported at the 31st European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) that the CoronaVac vaccine provides 83.5 percent protection against symptomatic COVID-19 infection.
The researchers also discovered that the vaccine provides 100 percent protection against being admitted to the hospital because to COVID-19. The degree of certainty about the precise level of protection against hospitalisation was, on the other hand, quite low because these were preliminary findings.
The findings, which were published in The Lancet, provide more evidence of the efficacy of SARS-CoV-2 vaccinations in preventing disease.
Vaccines against COVID-19
Science has been rushing to develop vaccinations that are both safe and effective since the advent of SARS-CoV-2 and the rapid spread of the virus throughout the world.
Early vaccine candidates, such as the Oxford-AstraZeneca vaccine and the Pfizer-BioNTech vaccine, have shown promising results in clinical trials, and scientists have demonstrated that they are successful in real-world situations.
In spite of this, the sheer size of vaccine distribution on a worldwide scale, the novelty of SARS-CoV-2, and the cutting-edge technology behind some of the current vaccinations all point to the need for additional vaccine research and development.
Forni and Mantovani, representing the COVID-19 Commission of the Accademia Nazionale dei Lincei in Rome, state that “the possibility of having numerous vaccines based on different technologies will allow us to select those that can be most effective in specific phases of the pandemic and different parts of the world.”
The CoronaVac vaccine is an inactivated vaccine. The presence of an inactivated version of SARS-CoV-2 indicates that it is unable to replicate itself.
However, the immune system is still capable of training antibodies against the inactivated virus despite these limitations. In the event that the person is exposed to the virus, their body will have a greater chance of resisting the infection or at least minimising the severity of the infection.
As a result of prior results, CoronaVac has been granted emergency use licence in 37 countries, and it has been granted emergency use authorisation by the World Health Organization (WHO) on June 1, 2021, according to the WHO.
CoronaVac, on the other hand, is still undergoing clinical studies.
The most recent evidence
The most recent findings came from a phase 3 experiment conducted in Turkey. There were 10,029 participants in this double-blind, randomised, placebo-controlled experiment who were randomly assigned to receive either two doses of CoronaVac 14 days apart or a placebo.
The study participants were all volunteers ranging in age from 18 to 59 years. People with a history of COVID-19 infection or who were taking immunosuppressive medication were excluded from the study. People who were pregnant or breastfeeding, who had allergies to the vaccine’s ingredients, or who had an autoimmune disorder were also barred from receiving the vaccination.
The scientists were especially interested in whether the vaccine might prevent COVID-19 infection, which was validated by a PCR test performed at least 14 days after a participant’s second vaccination and before the third vaccination.
The follow-up period lasted 43 days. However, when CoronaVac was granted emergency authorisation to be used in Turkey, the scientists anticipated a longer period of follow-up. However, this was curtailed. Giving the subjects a potential placebo in these circumstances would have been unethical under the circumstances.
Following an analysis of the data, the investigators discovered that CoronaVac provided 83.5 percent protection against symptomatic COVID-19 infection.
Nine people in the vaccine group got symptomatic COVID-19 14 days after their second immunisation, compared to 32 patients in the placebo group who developed the disease after their first vaccination.
According to these findings, the vaccine provided 100 percent protection against hospitalisation as a result of COVID-19 infection in children. However, due to the tiny number of persons who were admitted to the hospital, it is difficult to determine the exact impact on hospitalizations. Only six persons were admitted to the hospital after receiving COVID-19 in the placebo group, while no one was admitted to the hospital after receiving the vaccination.
CoronaVac has also been demonstrated to be quite safe. Adverse responses were recorded by just under 19 percent of the vaccine group and 17 percent of the placebo group, respectively. However, more than 90 percent of them were moderate, and over half of them lasted no more than one day.
As explained by Prof. Murat Akova, from the Department of Infectious Diseases and Clinical Microbiology at Hacettepe University School of Medicine in Ankara, Turkey, and his colleagues, “the world requires every feasible dosage of any safe and efficient vaccine against SARS-CoV-2.”
They go on to say:
“[O]ur results show that CoronaVac has high efficacy against symptomatic SARS-CoV-2 infection and [hospitalization], along with a very good safety profile in a population aged 18–59 years.”
There are certain limitations to the existing research.
“Because this study included a young and low-risk population with a very short follow-up period, additional data on the efficacy and duration of protection of the vaccine, as well as assessments of the vaccine’s safety and efficacy in older adult populations, adolescents, children, and individuals with chronic diseases,” the authors write.
They also point out that additional research is needed to determine whether the vaccination is effective against new strains of the virus, which is critical information to know.
In reality, according to a recently published study including over 10.2 million people in Chile who were vaccinated with CoronaVac, a very substantial piece of real-world proof is now accessible. Additionally, the study, which was published in The New England Journal of Medicine (NEJM), discovered that CoronaVac was effective, though not to the extent that the researchers had hoped for from the experiment.
Following the findings of a study conducted in Chile, the vaccine was 65.9 percent effective in preventing COVID-19 infection and 87.5 percent effective in preventing hospitalisation among those who had received a full course of vaccination.
Despite the fact that these numbers are lower than those reported in the interim analysis, the authors of the NEJM study conclude that the inactivated SARS-CoV-2 vaccine was successful in preventing COVID-19, which included severe disease and death.
It is critical to grasp the true efficacy of new vaccinations, especially in the face of developing variations, to rely on real-world evidence, which involves many more people than any clinical trial could possibly include.