The vaccine prepares the body to fight a specific type of infection or virus. A worldwide mass vaccination program has been developed to contain the Covid-19 pandemic. There is an abundance of information on this topic, but sometimes it is very difficult to make sense of it. We have compiled the most important facts about what a vaccine is as a type of medical substance and how it affects the human body.
The vaccine prepares the body to fight the pathogens that cause various infections – specific viruses or bacteria. Vaccines contain inactivated (killed) or weakened microorganisms that cause the disease, or their fragments. This forces our immune system to first recognize the invading enemy and then produce antibodies to learn how to fight it. You will not get sick from the vaccine itself, but some people may have a reaction to it, such as pain (or swelling) at the injection site or even a slight fever. But you will gain immunity to this disease. This is why vaccines are such a powerful tool in the fight against various diseases: they do not cure the disease, but prevent its development.
Vaccination is the administration of a vaccine against a specific virus or infection. Vaccination as a method of disease prevention was known in China as early as the 18th century, but the pioneer of vaccination was the English physician Edward Jenner, who noticed in 1796 that the easily transmissible cowpox virus provided protection against smallpox.
“We explain quickly, simply, and clearly what happened, why it matters, and what will happen next.” The number of episodes should not be changed. The end of the story: Podcast Advertising He tested this theory in practice, for example, by administering one of the first vaccinations to his gardener’s eight-year-old son with the contents of the cowpox pustule that had infected his milkmaid. Two years later, Jenner published his observations in the journal of the Royal Society, and the word “vaccination” was born – from the Latin word vacca, meaning “cow”. The invention of vaccination is considered one of the greatest achievements of modern medicine; according to the World Health Organization, vaccines prevent the deaths of 2-3 million people every year. The Centers for Disease Control and Prevention in the United States reports that before any vaccine is released, it undergoes rigorous testing in laboratories and on animals, followed by clinical trials on human volunteers, after which the vaccines are approved by regulatory agencies. Like any medical product, a vaccine may not be completely safe, but the benefits of its use far outweigh the potential risks.
For example, childhood diseases that were common a generation ago are now rare because of vaccination. And smallpox, which killed hundreds of millions of people, has been completely eradicated. But sometimes the path to victory over a particular disease can take many decades. Africa was not declared polio-free until August 2020, 30 years after the mass immunization campaign began. Experts warn that it may take many months or even years to vaccinate the inhabitants of our planet against Covid-19 to a degree that would allow life to return to normal.
When a new pathogen – harmful bacteria, viruses or fungi – enters the body, antigens, specific substances unique to these microorganisms, immediately trigger a protective response of antibodies – specific molecules produced by and dissolved in blood cells. Traditional vaccines are based on the principle of introducing weakened particles of a specific antigen into the body to familiarize the organism with the pathogen before encountering it in a normal environment. Defenses are then developed as the immune system responds to such a safe encounter just as it would to a real, aggressive pathogen. However, some anti-COVID vaccines are produced using a completely new method.
New methods were used for some COVID-19 vaccines. The vaccines developed by Pfizer-BioNTech and Moderna use part of the genetic code of the coronavirus, its messenger RNA. Rather than introducing a weakened virus into the body, this vaccine prompts our body’s cells to independently produce the same spike protein found on the surface of the virus that causes Covid-19, and to activate an immune response to produce antibodies to fight it.
The vaccine developed by the University of Oxford in collaboration with AstraZeneca works on a different principle: scientists took a slightly modified version of the common adenovirus that causes colds in chimpanzees and inserted a fragment of the genetic code of the new coronavirus. All three vaccines are licensed for use in the United Kingdom and the United States. Mexico and Costa Rica have already begun vaccinating with Pfizer’s vaccine, while the Brazilian authorities have given the green light to both Oxford’s vaccine and Sinovac’s CoronaVac.
The first coronavirus vaccination in Brazil was given to nurse Monica Calazan. CoronaVac, which is manufactured using traditional inactivated virus methods, is currently in use in China, Singapore, Malaysia, Indonesia and the Philippines. However, its efficacy has been questioned during late-stage trials in Turkey and Indonesia, as well as in Brazil, where scientists claimed its efficacy was only 50.4%. India launches two vaccines – the one developed by AstraZeneca and the University of Oxford (known there as Covishield) and Covaxin, developed by local company Bharat Biotech. Russia is using its vector vaccine “Sputnik V”, which has already been ordered by several countries. Argentina, for example, has purchased 300,000 doses for the initial phase of immunization, and the country’s president even publicly vaccinated himself with “Sputnik” to set an example for other citizens. The African Union has ordered 270 million doses from a range of suppliers – Pfizer, AstraZeneca (through India’s Serum Institute of India) and Johnson & Johnson, which is still testing its vaccine. This is in addition to the 600 million doses provided through the global Covax project, led by the WHO and the Gavi Alliance, which aims to ensure access to anti-COVID vaccines for the world’s poorest countries.
Herd immunity will help us return to normal life. Until Covid-19 vaccination is mandatory in every country in the world, experts strongly recommend that the majority of the adult population be vaccinated, with the exception of those for whom it may be contraindicated due to their health status. Experts say this is the only reliable way to end the pandemic. The WHO believes that 65% to 70% of people should have immunity before the chain of transmission is broken. Some people question the unprecedented speed with which anti-COVID vaccines have been developed. In fact, it normally takes years for scientists to develop new vaccines, but under the conditions of a pandemic and with the active collaboration of scientists from different countries under the auspices of the WHO, this has been possible in a much shorter time. At the same time, it should be noted that the most recent, third phase of clinical trials has not yet been completed for any of the vaccines, so any claimed results are preliminary. In summary, vaccinating billions of people will help stop the transmission of the virus that causes Covid-19 and achieve herd immunity. And once we do, we can return to normal life.