The vaccines designed by Pfizer BioNTech and Moderna are 95% and 94% effective in preventing COVID-19, respectively, but they provide 100% protection against severe forms of the disease, explains epidemiologist Ştefan Dascălu.
In the same way, those immunized with AstraZeneca vaccines are protected, although on paper, they are somewhat less effective in preventing the disease. At the same time, he draws attention to the risk that a new pandemic will emerge after it becomes a thing of the past.
The truth: We have 3 vaccines with which we hope to stop the pandemic, but recently there have been several mutations in the virus. How effective are these vaccines against new strains?
Ştefan Dascălu: Depending on the vaccine, Pfizer and Moderna have already been evaluated in the context of the new strain in South Africa and remain effective. From what I understand, a study would have shown that AstraZeneca is not so effective in preventing symptomatic infections, only that the study was done on a relatively small number of participants and the average age was 31 years. So these are young people, who were not prone to complications anyway, proof that no severe cases were registered among them. I am optimistic and expect the vaccine to continue to be able to prevent severe cases.
– You said that the AstraZeneca vaccine would not be as effective for the South African strain. Is there a risk that those infected with this strain will develop severe forms of the disease that will lead to death even if they have been vaccinated?
In this context, it is important to specify what this symptomatic infection means, because the symptoms may be those of a common cold, in which you cough a little, your head hurts a little and you recover after a few days, or they may involve some complications, hospitalization. , and in the most severe cases even intensive care or even death.
The good news is that all vaccines manage to prevent the latter case, proof that they are 100% effective in preventing severe cases after the two doses or even after the first. Of course, it takes a certain amount of time for the immune response to develop. Because of this, if someone becomes infected before being vaccinated or just a few days later, the vaccine will not help them much.
An unpredictable virus
The evolution of virulence is a rather complex phenomenon and depends on other parameters, such as the mode of transmission of the virus, the history of the virus in relation to the species it infects, but also other viral properties such as how the virus hides from the immune response. Because he also has certain mechanisms to fight even against our immune response or to hide from our immune response.
Obviously, there is a correlation between the virulence of an infectious agent and transmissibility, and usually a highly contagious virus does not cause very high mortality. But we cannot know how it will evolve over time. Regarding the second part of the question, the vaccines will be perfected in such a way as to provide protection in case of future mutations, and in time we will end up with a regular vaccination, just like in the case of influenza.
– Many experts point out that once we get rid of COVID we run the risk of facing other pandemics. Where could the danger come from?
Of course, there are many dangers and many potentially dangerous viruses, but I will refer to a relatively well-known one, the bird flu virus. This virus does not spread easily to humans, but has the potential to mutate. Through repeated contact with humans, there is a risk that the virus will bypass this species barrier.
These things happen, really less often, but they can happen. Then the risk is very high, because our immune system is not adapted to fight it, mortality and damage caused by it are very high. That is why there is this permanent danger and influenza viruses are monitored not only to prevent damage to agriculture. Mortality can reach 50% in this case, so without panicking, the situation must be taken seriously.
CV Ştefan Dascălu
Name: Ştefan Dascălu
Place of birth: Suceava
Age: 25 years old
Education: Bachelor of Biological Sciences and PhD student at Oxford University
Occupation: researcher in immunology
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