We are dreaming of a return to the pre-pandemic world. For almost a year we have been facing the consequences of SARS-CoV-2 coronavirus, which causes a dangerous disease called COVID-19. Thanks to the mobilisation of scientists around the world, vaccines have been developed. The process of voluntary immunisation began in December 2020. What are vaccines? How do they work? Should we be afraid of them? We have asked Dr Katarzyna Kasperkiewicz, immunologist from the Faculty of Natural Sciences at the University of Silesia.
Dr Małgorzata Kłoskowicz: At first we frantically followed the statistics of new confirmed COVID-19 incidence, then we slowly got used to subsequent safety rules. Both face masks and social distancing became our daily reality. We were also waiting for any good news with hope. It seemed that the information about the beginning of general COVID-19 vaccination in the Great Britain would finally give us relief. However, several new concerns appeared. What do we know about the vaccine?
Dr Katarzyna Kasperkiewicz: The subject is difficult and multi-threaded. Let us start with the most important issues. The vaccines introduced in the market by Pfizer/BioNTech and Moderna are designed to make our immune system respond a lot more quickly and effectively to contact with SARS-CoV-2. The key thing is that the preparation used in the vaccine does not kill the virus, but it is supposed to prevent the development of fully symptomatic, dangerous disease known as COVID-19 in our organisms. In practice, this means that general immunisation is not intended to directly eliminate coronavirus, but to mitigate the effects of its virulence against the human organism. As a result of the vaccination, coronavirus penetration into our cells will be much more difficult.
M.K.: How does the vaccine work?
K.K.: Vaccine is a certain specific preparation which may be administered intra-muscularly or subcutaneously in order to produce immunity against a particular microorganism. We talk about anti-bacterial and anti-virus vaccines. The important thing is the vaccine composition. It has to contain a non-toxic antigen, i.e. a substance which is harmless for human organisms. There have been various cases in the history of vaccinology (science of vaccination). It’s been a long time since we stopped administering living (or active – in case of viruses) microorganisms during immunisation. Such solutions were used, for example, in polio vaccine production. Although the vaccine contained the virus causing the disease which was weakened and virulence-free (less virulent), it was capable of transforming in the organisms with a decreased immunity, which meant that the effect was counterproductive, and the patient would ultimately become ill with polio. However, I would like to strongly emphasize that such solutions have been eliminated. Another type of antigen applied in vaccines could be a piece of microorganism mRNA. This particular technology is used in the vaccine that we are talking about right now. It is a relatively new subject, which has been developed in immunisation for approximately twenty years.
M.K.: Injecting any piece of coronavirus does not sound encouraging…
K.K.: Antigen in the form of mRNA is a certain segment of ribonucleic acid, short genetic information of SARS-CoV-2 coronavirus administered intra-muscularly, in the form of an injection. Therefore, it does not reach the blood stream. Once it is injected, our organism immediately begins the process of reading and “transcribing” the information in ribosomes. There is no option that mRNA gets through to the cell nucleus and damages our DNA in any way – the structures and the location are different, so it can neither harm us or cause COVID-19 disease from the biological or medical point of view.
M.K.: You have mentioned that the technology had been developed for many years. What proved to be the greatest challenge?
K.K.: Antigen in the form of mRNA must be stable. It was usually subject to quick degradation after collecting genetic material from the virus. However, the scientists had to be sure that once it was administered in the vaccine, it would survive in our organisms in an unchanged form until the antibodies were formed. Therefore, intense research focused on searching for something that would provide antigen with stability. And what proved to be the right carrier? Nanolipids, i.e. small lipid particles which constitute the casing for mRNA fragment, responsible for antigen stabilisation in the vaccine. In my opinion, this is an inventive and very modern technology.
M.K.: So let’s assume that we have decided to be immunised, we get the doctor’s approval, and we are consequently vaccinated against COVID-19. What will happen to our organism after injecting a piece of genetic information of SARS-CoV-2 coronavirus?
K.K.: To answer this question, first we have to understand how the human immune system operates. First of all, human organism may react to something which is foreign to it. Every day we are bombarded by billions of particles, a vast majority of which does not activate immunity mechanisms. Due to this, vaccination is performed only in the cases when we know that such reaction may occur. This is the case of SARS-CoV-2 virus. When applying a specific antigen, we expect to ultimately obtain two types of immunity. The first one, of humoral type, means the process in which activation of B lymphocytes occurs. Only stimulated B lymphocytes (in this state referred to as plasmatic cells) can produce antibodies. It is them that we are most interested in, because they are the specific proteins dedicated for this particular antigen. We could compare the antigen-antibody reaction to the correlation between a lock and a key. One has to match the other perfectly. In other words, in the case of COVID-19 vaccine, a piece of mRNA of coronavirus SARS-CoV-2 that codes only one selected virus protein (sic!) is introduced. It induces the cells in our organism to produce a virus antigen, thanks to which we should respond to this infection more effectively and quickly. Therefore, with the vaccine we give our cells something that they are expected to produce. The stimulated immune system should react by activating B lymphocytes, which, after some time, will produce antibodies specific only for this type of antigen. First, IgM-class antibodies will be produced. They protect us only for 4-5 days, and then disappear. If the antigen continues to stimulate our immune system, IgG-class antibodies are produced. It is precisely this type of antibodies that we are looking forward to. This is the so-called strong and long-lasting immune system response. The antibody is of key significance, because not only will it recognise a particular microorganism in the future, but it will also bind with it, preventing it from penetrating into the cells and causing the disease. The second type of immunity is based on cell response. This time, the main role is played by cytotoxic T lymphocytes with proper mechanisms for neutralising a bacterium or virus. Therefore, an ideal vaccine should operate on both levels. This is not always the case, because a lot depends on the type of pathogen that we are dealing with.
M.K.: The life-saving blood plasma of convalescents has also been much spoken about for many months.
K.K.: This is the so-called passive immunisation, i.e. a form of… vaccination recognised in vaccinology. The difference is that we provide our patients with ready-made antibodies instead of antigens. This solution results in almost immediate activation of defense mechanisms in the patient’s organism, thanks to which the reaction to multiplying virus cell structures is accelerated and intensified. This is particularly important in case of the individuals who suffer from COVID-19 severely, when their organism is too weakened to beat the dangerous “alien” on its own. This method has already been known for a long time. First of all, it is ideal in the case of quickly developing infectious diseases, with a severe course for the patient, such as tetanus or rabies. Secondly, antibodies are administered e.g. when the doctor or the nurse had contact with the blood of a person who suffered from viral hepatitis, for example. Thirdly, this method rescues people whose immune system does not function properly. Administering convalescent plasma allows to buy time in the case of individuals who suffer from COVID-19 most severely. Ready-made antiibodies operate when coronavirus has already penetrated into our cells, and may have created millions of its copies. In such situation, we don’t know whether the administered antibodies will neutralise all virus particles. Moreover, the “lifespan” of antobodies administered in this way in our organism is relatively short. If the entire pool given to the patient has been used up, there is nothing to protect us. And vaccination is supposed to stimulate our organism to produce antobodies on its own. Such antibodies may be produced continuously, if only cells are stimulated with antigen. This prevents coronavirus from getting inside the organism and multiplying suddenly, and in consequence – from developing a fully symptomatic disease.
M.K.: COVID-19 vaccination process is in progress. However, it is not mandatory…
K.K.: It shouldn’t be. The first decision will be ours. The second one will be taken by the physician who qualifies us for vaccination. I find it hard to imagine a different scenario. The physician should get to know the history of our diseases, to be able to respond which way is more advisable in our case. They will assess the opportunities and risks. Many patients are already asking their physicians what they should do. Should a patient with diagnosed chronic leukaemia get vaccinated? If they contract COVID-19, the probability that they will not survive is very high. The supervising physician will take it into account.
M.K.: The elderly people, pregnant women and allergy sufferers all have their doubts… We also have to face the so-called fake news.
K.K.: This is another very difficult topic. I am convinced that none of the companies introducing the vaccine to the market – neither Pfizer, nor Moderna – would risk its reputation if they were not confident about the product’s quality. We should avoid false, unproven information and data misinterpretation. The fact that there are currently no research results concerning adverse postvaccinal reactions in pregnant women does not mean that immunisation will definitely cause damage to them or their children. Moreover, the websites of the above-mentioned companies include comments referring to many “popular” doubts. This applies to each of the listed groups. Fear is a natural reaction. I realise that the disease is new. However, vaccinology is a science with several hundred years of experience, and the technology used in COVID-19 vaccine was being developed by independent groups of scientists for many years. Let me repeat once again: let’s trust our physician. The process of treating every disease is based on trust. Combatting coronavirus requires the patient’s honesty and huge knowledge of the physician who should follow carefully all scientific information (and interpret them properly) to ensure the safety of their patients.
M.K.: We cannot avoid the subject of adverse vaccine reactions. What organism reactions to COVID-19 vaccination are we aware of?
K.K.: Local inflammation with redness may occur in the injection area, sometimes with a slight pain. This is the reaction for a majority of vaccines. Research has also indicated the possibility of headache or general fatigue, which most frequently disappears on the following day. After administering the vaccine, it is advisable to stay in the medical unit for about 30 minutes to monitor any potential adverse reaction of the organism to the preparation. In this case, we most frequently talk about allergic reaction. If anything happens when the vaccine has been administered, it should be reported to the vaccination point, from where the information will be communicated to the producer. Based on this, the frequency of adverse vaccine reactions is estimated and such data are published in the recommendations for physicians and descriptions of preparations. I want to emphasize that companies are obliged to disclose such data. They do not hide anything from us.
M.K.: In practice, only a certain percentage of the society will get immunised. What does it mean from the perspective of global fight against coronavirus?
K.K.: All hope lies with herd immunity. We already know that a considerable percentage of people will not get vaccinated. Some of them will simply not agree, while others will not be qualified by the physician. What does it mean? Simply speaking, when coronavirus “finds” a stronger, vaccinated person, it will gradually modify. Even non-vaccinated organisms should be able to beat such less virulent form of the virus. And the pandemic will cease with time.
M.K.: My intuition tells me that this is an optimistic scenario that apparently we all want to believe in…
K.K.: Unfortunately, the less optimistic scenario may also come to reality. If there are really many non-vaccinated individuals, then coronavirus „will strengthen” and continue to threat everyone – both the ones who got vaccinated, and those who did not receive the vaccine for different reasons. We are talking about extremely complex mechanisms. Microorganisms are not passive in this struggle and they… mutate, adapting to the changing conditions. They want to survive, just like we do. This means that the pandemic may last longer, and immunisation will be seasonal, as in the case of flu vaccinations. If only one element in coronavirus structure changes, our immunity system will not recognise it. I have already mentioned the key and lock rule: this compliance must be 100%.
M.K.: The hope I had a moment ago has just faded…
K.K.: I think that everyone of us is tired with the pandemic of… fear. The ongoing anxiety and stress which we’ve inevitably experienced for months also have negative impact on the efficiency of our immune system. One of the reasons behind its malfunction is a high level of cortisol. I have recently talked to a lady who told me how happy she was when she heard about the vaccine. The thought that there is something which may protect us against this difficult opponent gives us hope, improves our well-being, becomes a source of mental comfort and may consequently increase our immunity. I believe in it, too. Therefore, I’m watching at the activities of scientists around the world, and I’m looking at what started in the Great Britain in December with hope.
M.K.: Thank you for the interview.