Three vaccines are before the final approval phase – What we learned after the announcement of the University of Oxford – What does Phase mean? 3
The scientific community is well on its way to research into developing a vaccine that will shield humanity against the SARS-CoV-2 virus that causes COVID-19. However, a number of questions have arisen regarding the vaccine as a measure of protection against the new coronavirus. There are three vaccines that are already in advanced phase clinical trials 3, ie one step before submitting an approval request to the competent regulatory authorities.
This is mRNA-1273 of the American biotechnology company Moderna, the AZD1222, jointly developed by the University of Oxford in the UK with the pharmaceutical company AstraZeneca, and Ad5-nCoV, developed by the Chinese biotechnology company CanSino Biologics. Based on the data that have seen the light of day and concern the Phase 1 the clinical trial of the three vaccines, appear to cause the development of a sufficient number of antibodies in the body of the vaccinated volunteers. This is a good basis for continuing Phase clinical trials 3 and a promising prospect for the usefulness of vaccines, whenever they are finally decided to be suitable for widespread use. Given, however, of the view that SARS-CoV-2 came to stay and therefore we must learn to live with it, as with influenza and other respiratory viruses, we will try to answer 10 key questions concerning the COVID-19 vaccine. The answers are given on the basis of scientific data that have emerged to date from clinical trials, but also pre-existing knowledge from the development of vaccines in general.
Which guy vaccine is more effective;
According to the above, three vaccines lead the scientific race for immunoprotection of SARS-CoV-2 from 23 which is in clinical trials in humans and 150 and now which are still under research. Moderna is based on the so-called messenger RNA (mRNA), CanSino uses a non-replicating viral vector and the University of Oxford uses a recombinant adenovirus vector. Each of these vaccine platforms has advantages and limitations. Important features include the speed and flexibility of construction, safety and induction of a satisfactory immune response, the profile of chemical and cellular immunogenicity, the duration of immunity, the scale and cost of construction, the stability of the vaccine. The most likely scenario is that no vaccine or vaccine platform will be able to meet all global needs on its own and therefore we will need more than one type of vaccine to meet the many different needs that may exist in different parts of the world and in different different populations (e.g. younger versus older, special vulnerable groups etc.).
What efficacy should the vaccine have?;
US study published in the American Journal of Preventive Medicine in June, based on a computational algorithm, concluded that the effectiveness of the vaccine should be at least 60% to be considered as fulfilling its purpose. Note that the seasonal flu vaccine has an efficacy ranging from 20% to 60% annually, while respectively of measles 95%-98%.
What will be born with the safety of the vaccine;
Any medicine and vaccine, ascertained, accompanied by side effects, the frequency and severity of which determine the safety of the final product. Preliminary clinical trials of the three candidate vaccines for COVID-19 showed that the most commonly reported side effects were all mild to moderate in severity and involved injection site irritation., fever, muscle algae, sickness, chills and fever, treated with appropriate medication. Of course, it is not excluded in the Phase 3 or later report rarer adverse reactions affecting vaccine approval procedures. In each case, due to the health condition caused by the pandemic, the advisory committees will weigh the benefit balance in detail – before the approval of any vaccine.
What percentage of the population needs to be vaccinated to stop the coronavirus;
As long as any vaccine is effective and safe, Another crucial factor that concerns scientists is how many people will have to be vaccinated against SARS-CoV-2 to shield humanity from a new pandemic. In the same American study, always based on the algorithm, It is estimated that approximately 60%-70% of the global population to stop the spread of SARS-CoV-2 in the community.
When will the vaccine be available?;
The positive preliminary results of the clinical trials of the three vaccines have undoubtedly caused excitement in the public as well as in the scientific community.. In fact, Dr. Adrian Hill, director of the Jenner Institute University of Oxford, has been quick to state that "a vaccine later this year is not considered unlikely. Of course, many things must be done correctly to achieve the goal within 2020. ". However, Independent experts estimate that before his means 2021 we should not expect the official release of a vaccine, despite the fact that some of the pharmaceutical companies involved have declared productive readiness. For example, AstraZeneca has announced that the first 15,2 millions of doses of AZD1222 will have been produced by December 2020 and the rest 15,2 millions by January 2021. However, Mike Ryan too, Head of Emergency Situations Program at the World Health Organization (WHERE), last week told us that "a vaccine against the new coronavirus can not be expected before the beginning of 2021", clarifying that "realistically it will be the first part of next year before we start seeing people being vaccinated".
When should the vaccination be given?;
From the experience so far from seasonal flu vaccine, are needed on average 14 days from the day of vaccination to produce a sufficient number of antibodies in the body and to consider the person protected. Seasonal flu viruses in Greece circulate from about the end of November until the beginning of April next year, with peak cases usually in February.
So, The seasonal flu vaccination is recommended in October – November of each year. The coronaviruses, to whose family SARS-CoV-2 belongs, have a longer circulation period, from October to April of the following year. Therefore, A key question that also affects the effectiveness of the COVID-19 vaccine is when should the vaccine be given to prevent the body from producing antibodies.. For example, from the preliminary data of AZD1222 it seems that they were needed 14 days for the body to produce T-cells and 28 days to detect neutralizing antibodies. Theoretically, Well, vaccination should be given at least 1,5 month earlier than the start of the coronavirus circulation period, that is, around mid-August.
A single vaccination is sufficient;
Despite the encouraging results in the development of a sufficient number of antibodies with the three vaccines mentioned above, The question remains whether the one-time vaccination will be sufficient to provide adequate protection.. However in the Phase 1 clinical trials and the three scientific teams also gave a booster dose to the volunteers. And this was done to test whether the booster dose helps produce more antibodies, but also if this helps maintain the antibodies for a longer period of time. What is certain is that the vaccine, either in a single dose, either in two or more, should offer immunoprotection for more than six months to cover the release period of the new coronavirus.
The composition of the vaccine is constant or modifiable;
From the scientific data so far, The new coronavirus has undergone some mutations since it crossed the borders of Asia and entered Europe, America and the rest of the continents. The ability of viruses to mutate affects the effectiveness of vaccines. A typical example is the flu vaccine, which due to the predominance of different strains of the virus from year to year its composition is parameterized to catch the dominant strains. Similarly, researchers are already studying this parameter in relation to SARS-CoV-2. Although it mutates at a slow pace, surely any change in the virus can affect the action of the vaccine. At present, the mutations have helped it to spread more easily, but without this having affected the behavior of the antibodies against the virus. Studies have shown that antibodies from patients with the original composition of SARS-CoV-2 offer protection against the newer version of. This makes experts believe that a vaccine with a stable composition will be effective against the new coronavirus.
A vaccine for everyone;
All vaccines under development for COVID-19 have one thing in common: their clinical trials are performed on healthy volunteers, age 18-55 years. This practically means that vulnerable groups have been excluded from research, such as the elderly, children and people with comorbidities and aggravated medical history. The human immune system shows functional fluctuations with age and the general state of health of the individual. Simply put, the body of the elderly responds differently to a vaccine and otherwise to children. Therefore, Before approving any vaccine for SARS-CoV-2 it should be clarified whether it is suitable for all population groups in order to be safe and effective. Sure, It is possible to obtain approval initially for healthy adults, the vaccination of which will act as a shield of protection for the vulnerable groups of the population.
Vaccine accessible to all;
Regardless of when a vaccine for the new coronavirus will finally be approved for widespread use, Several countries have already rushed to pre-order some doses of it. For example, Germany, France, Italy and the Netherlands have pre-agreed with AstraZeneca, if AZD1222 proves effective, to be procured up to 400 millions of doses, while Brazil and the United Kingdom have applied to receive 100 millions and the US 300 millions of doses. In fact, the US government has also stated that it will pay the amount of 1,95 billion. dollars to buy and 100 millions of doses of the BNT162 vaccine, jointly developed by the American pharmaceutical company Pfizer Inc. and the German BioNTech, provided of course it proves safe and effective.
From the above it is clear that both the adequacy of the doses of vaccines produced and the price of the final product are small thorns in the fight against SARS-CoV-2. WHO is in constant discussions with the production companies and its member countries to guarantee universal access to possible vaccines for all mankind. "Vaccines for this pandemic are not for the rich, it is not for the poor, but for everyone ", has been emphatically stated by Mike Ryan. On the same wavelength, the Johnson Pharmaceutical Companies & Johnson, AstraZeneca pledge to make vaccines available to US congressmen without financial gain. On the other side, the Pfizer, Merck and Moderna say they will not sell at any cost the new coronavirus vaccines they will make.