[ad_1]
According to Aurelia Žvirblienė, a professor at the Vilnius University Life Sciences Center (VU GMC), the latest achievements of Pfizer and Moderna in the development of coronavirus vaccines are truly impressive: they have reached an incredibly high level of effectiveness.
Pfizer and Moderna’s reports on the highly successful results of the third phase of vaccine clinical trials received global attention this week. What did these reports show?
We have all read the latest reports on the impressively high efficacy of vaccines developed by these companies in research, up to 95%. This means 95 percent. volunteers who received test doses of the vaccine in clinical trials were protected from coronavirus infection.
With regard to the vaccines developed by these companies, it is also important to note that both Moderna and Pfizer use an entirely new vaccine development technology based on the informational RNA encoding a viral protein. The RNA molecule is “packaged” in a lipid layer to enter cells and not break down. When administered, the RNA enters cells and they begin to produce a viral protein, which triggers an immune response. Thus, the RNA in the vaccine is like an instruction that vaccinated human cells produce a virus antigen, which “trains” the immune system to recognize and inactivate the virus.
Different vaccines activate immunity differently. How does this work and are there advantages between vaccines developed with different methodologies?
This RNA format is certainly not the only one currently used in vaccine development. Another innovative format is DNA virus-based vaccines. The vaccine was developed by researchers at the University of Oxford and the pharmaceutical company AstraZeneca. They used an attenuated adenovirus and inserted a gene encoding a coronavirus protein into it.
As with the RNA vaccine, the adenovirus must first enter the cells, which then begin to produce the coronavirus protein. In both cases, the vaccine does not contain a viral antigen, but only an ‘instruction’ for its production. The real virus works in a similar way: it enters the cell and causes it to produce new viruses.
Other companies use the principles of vaccine development that we already know, which are based on the use of viral proteins. In this case, the vaccine already contains a viral antigen that triggers an immune response.
One method cannot be said to be superior to another. More importantly, the viral antigen elicits a protective immune response by activating both B lymphocytes, which produce antibodies, and T lymphocytes, which produce a cellular immune response. In the case of the coronavirus, no one knows in advance what type of vaccine will be most effective.
During the pandemic, the question was constantly raised whether a vaccine could be developed that works equally for all age groups. Why is it so difficult to develop a universal vaccine?
The group most vulnerable to this virus are the elderly, who have a higher risk of complications. In old age, the immune system is less able to respond to new and unknown antigens.
As a result, researchers and the public have questioned the effectiveness of the vaccines that are being developed for all age groups. If the vaccine only elicited an immune response in the young, the risk to the elderly, although reduced, would still exist. However, recent reports from vaccine companies say that the vaccines they develop have also been effective in the elderly group.
While the world rejoices at the achievements of Moderna and Pfizer, the process does not end with the development of the vaccine. What challenges lie ahead?
Innovative vaccine formats also dictate new rules. RNA molecules are not as stable as DNA or protein molecules and therefore must be stored at low temperatures. It is stated that the storage temperature of the Pfizer vaccine should be extremely low, even -80 ° C. Special equipment and refrigerators are required to keep the vaccine at this temperature. This can be a serious challenge for both vaccine transport and mass vaccination. Storage and transport conditions for other vaccines are simpler. Many countries start handling vaccine delivery in advance, before the vaccine registration process is complete, so there’s no need to waste time.
The probability of mutations also poses a significant challenge for future vaccination. Debates on this topic have intensified after the outbreak of a mutated virus in fur farms in some countries. Won’t mutations spoil the profits of vaccine developers?
Of course, the virus is changing, this is the natural evolution of the virus. Mutations of the virus occur completely by chance and, if favorable, such virus variants spread. However, the coronavirus is not an intensely mutating virus. Furthermore, outbreaks of the virus in tissue farms appear to be under control now and these virus variants have not become widespread. The situation should be monitored regularly by examining the viral genome.
The longevity of the immune response to the injected vaccine is also one of the factors that does not bring peace to the world tormented by a pandemic. Is it possible to predict how long newly developed vaccines will be effective in humans?
Vaccine clinical trials confirm that an immune response is triggered after vaccination. However, the long-term nature of immunity is difficult to judge until now, as little time has passed since the volunteers were vaccinated. Data from long-term immunogenicity and efficacy studies will also show future vaccination strategies, as no one can say for sure yet whether the vaccine will last long, such as decades (like measles, rubella vaccines, etc.), or whether regular vaccinations will be needed.
Our study in Nemenčin also demonstrated the fact that antibodies occur in naturally infected and relapsing coronavirus infections and persist for at least half a year, where a coronavirus outbreak occurred in a company in the spring. If the antibodies formed after the vaccine will last the same amount of time or longer, no one can respond yet.
Even the second wave of the pandemic, which is incomparably larger than the spring pandemic, doubts that it will be vaccinated against the coronavirus. What should you know about vaccinations for these people?
Doubts have always been and always will be. Some are waiting for more information about vaccines, others do not believe at all in the benefits of vaccines, and still others are misled by the constant flow of “melagus.” Once the vaccine is developed, those who want it will be able to get vaccinated and protect themselves. No one will be forcibly vaccinated.
Vaccines, like any other medicine, must pass through the “filters” of the competent authorities before they can be marketed on the European market. I have no doubt that the EU institutions, which do not employ political or business experts, will take the safety of vaccines very seriously. If there are doubts about the efficacy and safety of vaccines, such vaccines will not be registered and will not be marketed in the EU.
Prepared by Gediminas Dubonikas, VU GMC
[ad_2]
