A vaccine is a medical immunobiological agent containing weakened or completely inactivated pathogens of the disease, and in some cases their synthetic analogues. Such drugs contribute to the development of immunity to a certain antigen. The introduction of the vaccine into the body causes an immune reaction similar to the response to the action of the pathogen itself – antibodies are produced. At the same time, given the weakness of the pathogenic organism, the possibility of getting sick is minimal. Today, several types of vaccination drugs are used in medicine, differing in the mode of action and the form of release.
What are the vaccines
In modern immunology , several types of means are used for vaccination:
- live attenuated – contain a live, but weakened strain of the microorganism-the causative agent of the disease;
- inactivated – based on killed (inactivated) viruses and microbes;
- recombinant, subunit, polysaccharide, conjugated – contain only a certain part of the microorganism, for example, its shell, sugar or protein;
- anatoxin – based on toxins produced by the microorganism-the causative agent of the disease;
- mRNA – RNA is used, which “gives” the cells of the human body “instructions” on how to produce antibodies to a certain pathogen;
- with a viral vector – contain a neutralized virus used as a “vector” through which the body receives the information necessary to develop self-defense against a certain pathogen.
The most common form of the vaccine is a solution for injection (injections). Nasal sprays for vaccination are also available. Some drugs are administered by the scarification method, that is, cutaneous, while a small scratch is made on the skin, on which the vaccine is dripped. There is also an oral form of release – the drug is used through the oral cavity, for example, during vaccination against polio. And if earlier the oral vaccine was only in the form of a solution, now it is increasingly possible to hear about drugs for vaccination in the form of tablets. And are there really such?
Vaccine in pills: myth or reality?
Until recently, vaccines in tablets were not manufactured. But a few years ago, British scientists from Cardiff University created a non-biological drug that can be taken orally for vaccination against influenza. In the scientific world, this event is called a breakthrough.
Artificial proteins imitating peptides of real viruses were used as the basis of such a drug. Unlike biological peptides, synthetic ones are not exposed to the digestive system. It was this fact that made possible the existence of a vaccine in tablets.
The innovative vaccine has already proven its effectiveness. According to data published in the scientific publication The Journal of Clinical Investigation, the use of such a remedy causes a powerful immune response. The effectiveness of the drug was confirmed during a test on mice. According to the researchers, a similar result can be expected in the human body. However, scientists have recognized that so far we are talking only about vaccination against influenza. The development and study of vaccines in tablets against other diseases requires additional time.
No less relevant are the experiments of the American biotechnology company Vaxart, Inc. in the field of recombinant oral vaccines. The Corporation is currently working in several directions at once, providing for the possibility of vaccination with tablets for noroviruses, seasonal influenza, human pappiloma virus. The effectiveness of vaccination products created by Vaxart, Inc. should provide an enteric coating. Such a shell protects the tablets from the effects of acid in the stomach, allowing them to enter the small intestine, where the immune response to the penetration of the virus into the body takes place. The company uses a type 5 adenovirus to transport the antigen that generates a protective reaction. It delivers it to the epithelial cells.
Clinical trials, the second phase of which ended in 2018, proved that the tableted flu vaccine from Vaxart, Inc reduces the manifestations of the disease by 39%. In comparison, the injection form gives a result of only 27%.
How useful is the discovery of vaccines in tablets
Traditional vaccines used in immunology, including oral polio vaccines, require special storage conditions. In particular, medicines of this group must be stored and transported in refrigerators or freezers, which creates certain difficulties. Tablets do not need a special temperature regime, which greatly simplifies its use.
In addition , a means for vaccination in tablet form is also:
- absence of pain that occurs during injection vaccination;
- reduction of the number of allergic reactions in response to protein in the composition of solutions;
- expansion of the age group of vaccinated patients.
COVID-19 vaccine in tablets: is it possible
As for the COVID-19 vaccine, researchers around the world are also actively working to ensure that people can use not only drugs for intramuscular administration, but also in other forms for immunization. There is no publicly available anti-covid vaccine in tablets yet, but work is already underway in several countries to test an alternative vaccination.
The Nucleus Network company has started clinical trials of an anti-covid vaccine in the form of a nasal spray, and specialists of the biotech company Vaxxas have created a patch with microneedles coated with a drug for vaccination against COVID-19. And as the first tests on rats showed, this method of vaccination is even more effective than traditional injection – in mice, the immune response began to develop faster. Estonian scientists have also created a spray for the prevention of coronavirus infection.
Ukrainian scientists do not lag behind their colleagues. Last year, the Lviv Institute of Cell Biology of the National Academy of Sciences of Ukraine received a grant to develop a vaccine against COVID-19. To date, the project has almost been completed, research is being carried out in Poland on laboratory rats. The developers claim that they have “created non-infectious virus-like particles without nucleic acid.” If the effectiveness is proven, the drug will be widely used, manufactured in the form of a spray, tablets or medicine.
Nevertheless, Israeli scientists have been the most successful in developing tablet preparations for vaccination against coronavirus. The pharmaceutical company Oramed Pharmaceutical has started the first phase of testing an oral vaccine against COVID-19. According to the developers, if the effectiveness of the drug is confirmed, the drug will help significantly accelerate the pace of vaccination. Another important plus of antitussive tablets is that they do not require storage at low temperatures, which is mandatory for vaccine injections.
