Just before the end of September there are more than 300 candidate vaccines for coronavirus, 42 of these are tested in humans and 11 is in the final phase of clinical trials, as Elias Mosialos mentions in his new post.
The professor of LSE, analyzed the current landscape of coronavirus vaccines, however he stressed that they are not the final solution to fight the virus, but only a part of it.
How vaccines work;
Vaccines are based on the ability on the one hand to stimulate and on the other hand the memory of our immune system. That is, stimulate the body to produce its own antibodies against Sars-Cov-2, to then activate a series of reactions and fight the virus. When in the future the virus enters the body, either the existing antibodies or the memory cells will start the necessary neutralizing actions so that we do not get sick.
What types of coronavirus vaccines are being tested in clinical trials?;
There are many approaches that can be used, some more classic and others more innovative, and researchers around the world have already included them in the design of coronavirus vaccines.
With a 'classic' vaccine we can introduce the virus into our body, but inactivated (that is, the virus has been 'killed', for example from heat or chemicals).
We can also introduce into our body a piece of the virus - which is different from related viruses. Viruses enter human cells and use them as a laboratory to make the pieces they need one by one., so that eventually they multiply and acquire their functional form. Such a characteristic structural part, in the case of the new coronavirus, is the spike protein. Researchers have developed vaccines that give our cells the 'recipe', genetic information, to make parts of the coronavirus for example the pin.
These vaccines can:
contain modified common viruses that cause coughing or catching a cold. When we make the vaccine, these viruses will make the spike protein that the coronavirus uses to attach to healthy human cells..
are mRNA and DNA vaccines, as they are called, that will introduce the ‘recipe’ into our cells so that our cells can make the protein spike,
are fragments of the spike protein but without the genetic information.
In each of these approaches, The goal is for our body to make antibodies against this spike protein in response.
From 42 vaccines in clinical trials or already licensed for limited use in some countries:
6 are vaccines that contain an inactivated virus (such as Sinovac and 2 Sinopharm vaccines, where and 3 have been restricted.
8 are vaccines based on a viral vector (such as the Russian vaccine, the Chinese CanSino vaccine, and the AstraZeneca vaccine)
11 are mRNA-DNA vaccines (such as Moderna and Pfizer),
17 are protein vaccines (such as Novarax which entered phase III),
So when can we expect results?;
Scientists' predictions about when the analysis of the effectiveness of the first vaccines will begin after the completion of phase III vary from the forthcoming 2-3 months, to the middle of it 2021:
Η Pfizer / BioNTech said it would have enough Phase III data to start analysis in late October.
Moderna, which already has more than 25.000 participants in this phase of clinical trials and more than 10.000 have received both doses of the vaccine, said last week that an interim analysis of test results is likely to begin in November and possibly in late December.
AstraZeneca considers that before the end of the year it will be close to submitting approval of regulations. About 18.000 people in the United Kingdom, the USA, South Africa and Brazil have received the AZD1222 vaccine so far. But clinical trials in the US of the AstraZeneca vaccine have stopped and these estimates may be overly optimistic..
As I mentioned recently, In clinical trials, those who receive the vaccine do not have the disease at the same time. Clinical trials have focused on demonstrating the safety and efficacy of the vaccine. Both are evidenced by the immune response of the volunteers. After the vaccination, we actually expect the volunteers to be exposed to the virus and to see if the vaccine protects them.. But this process can take several months, because many vaccinated volunteers may never catch the disease. Especially in a pandemic situation where we try with measures to stop the dynamics of the spread, and isolate carriers and patients.
Despite the announcements and statements of company executives, both Pfizer and Moderna Phase III clinical protocols make it very clear that they will not know if their vaccines will work until December / January at the earliest. However, if we look at the clinical trial protocol, we see that this estimate is not certain.
In the case of Pfizer they will be waiting to be exposed 164 of those vaccinated against coronavirus, to arrive at real efficiency. An independent study committee will also review the data on 62, 92 and 120 cases.
In the case of Moderna the evaluation will be done after exposure to the virus 151 vaccinated and the independent committee will review the data after the first 53 and after 106 cases.
It also matters how much and when these vaccinated people became infected. These numbers may sound small, but I remind you that in England, where disease-causing studies will be done, they are oriented towards a deliberate infection 100-200 volunteers. The committee, and later the regulators, should feel confident that the trend through primary analysis will continue in the coming months or years of the study, in which more participants could get sick.
Pfizer clinical trial has surpassed them 30.000 volunteers and over 12.000 have taken the second of the two doses, which are three weeks apart. Pfizer clinical trial begins measuring COVID-19 infection cases, 7 days after the second dose. Moderna takes the second dose 4 weeks after the first and the analysis of the cases to be exposed, starts two weeks after the 2nd dose (reported that approximately 10.000 by most of them 25.000 volunteers have received the second dose.) Remember that on 22/10 The FDA Advisory Committee on the course and criteria for vaccine evaluation will also be convened.
in conclusion, the discussion about coronavirus vaccines exists 3 components:
the variety of approaches used by researchers,
the impressive growth rate of new vaccines
the dependence of the world community on the approval of vaccines given the lack of drugs so far, in addition to dexamethasone which significantly reduces mortality.
I mention it often, how to wait for the results of the evaluation of clinical trials, the importance of evaluation by independent and international regulators and transparency in the announcement of results. Why I refer to publications and developments with restrained optimism and realistic time requirements;
After the evaluation of the results of the phase III clinical trial, a successful vaccine could be approved by the competent regulatory authority allowing the vaccine to be delivered early to vulnerable groups. It will probably take an additional six months for a second phase III data analysis, before vaccines can be made available to wider public vaccination campaigns.
Previous research on coronavirus vaccines has also identified some challenges for COVID-19 vaccine development., such as the provision of long-term protection but also the protection of the elderly and people taking immunosuppressive drugs or have a reduced immune response. These groups are at greater risk of developing COVID-19 severely. However, We know that older people usually do not respond to vaccines as well as younger people, and booster doses may be needed. An ideal COVID-19 vaccine would work well for both the vulnerable and this age group.
It is extremely unlikely that any of the first vaccines will be 100% effective. Regulators have set the 50% effectiveness as a criterion for the approval of vaccines. With 50% efficacy is doubtful whether we will achieve herd immunity even if the whole population is vaccinated, which is also extremely doubtful. Nevertheless, a vaccine even with 50% effectiveness will be a major advance in the fight against coronavirus.
End, although it is unlikely to have a vaccine with efficacy over 50% the fact that we will have many types of vaccines, as I explained, can have beneficial effects. Simply put, a vaccine may not be effective for some groups but may prove to be very effective for others. This will require the supply of different types of vaccines.
It will therefore be imperative that we continue to implement public health protection measures after the discovery of new vaccines., until we can significantly reduce the spread of the virus, and worldwide but also in our country.
The final treatment of the coronavirus will come from a combination 5 parameters
Implementation by the state and businesses, measures against the spread of the virus: frequent transport, strengthening teleworking, meters of frequent ventilation with fresh air indoors (e.g. in schools and workplaces), strengthening the NSS, immediate tracking and isolation of patients and more frequent use of diagnostic tests, interdisciplinary approach to pandemic monitoring and task force establishment (with the participation of specialists and experts in multiple and not only medical specialties) for the development of alternative approaches to dealing with the pandemic depending on the developments in our country and internationally.
Implementation of public health rules by citizens,
Use of medication (dexamethasone and possibly in the coming months and antibody treatments),
First generation of coronavirus vaccines
Second, and probably more effective, generation of coronavirus vaccines.