COVID-19: everything you need to know about vaccination

The introduction of special drugs - vaccines - may be the only way to stop the pandemic spread of COVID-19. There is a lot of talk about this topic, but for the average person, there are still a lot of questions that we will try to answer.

What is the COVID-19 vaccine?

The main purpose of vaccination is to prepare the body for a worthy response to the penetration of an infectious agent (in particular, coronavirus). Preparations may consist of non-living (inactivated) or weak pathogens, or their particles.

The vaccine "teaches" our immune system to identify pathogenic microorganisms and produce antibodies against them. The introduction of a biopreparation is not capable of causing the development of an infection, but sometimes a person may have an individual reaction, for which one must be prepared. Most often, such a reaction is pain in the injection area, swelling, and a slight increase in temperature. In return, a person will acquire immune protection against a specific disease.

The essence of the “vaccination” is as follows: it does not cure the disease, but prevents its development.

Are COVID-19 vaccines dangerous?

Vaccination has been known to mankind since the 18th century: the first vaccination was made in 1774 by Dr. Benjamin Jesty. Since then, people have managed to eradicate many deadly diseases, including smallpox. Samples of the smallpox pathogen are preserved in only a few closed laboratories in the world.

Scientists have not yet been able to defeat poliomyelitis, however, thanks to vaccination, the incidence rate has dropped significantly, and today pathological cases are measured in units, but not in thousands, as in the last century. The incidence of tetanus, cholera, anthrax, and diphtheria has also decreased significantly. Many people survived by receiving vaccinations in time.

Today, nature has thrown down a new challenge to scientists – we are talking about COVID-19. Vaccination is also needed to stop the pandemic. However, vaccine development, despite the complexity of this process, is only the first link in the chain. The biopreparation must undergo thorough laboratory testing on animals, then clinical testing on humans follows, and only then can one expect to receive approval from the relevant authorities. In some cases, the vaccine is not recognized as completely safe, but is still approved by the WHO if the benefits of its administration significantly outweigh the probable risks. [ 1 ]

Rumors about the dangers of COVID-19 vaccines emerged after a number of reports of several fatal cases some time after vaccination with new biopreparations. However, such information is not entirely true: so far, not a single death has been recorded as a direct consequence of the "vaccination". Many patients died from a sharp worsening or exacerbation of the underlying chronic disease. Some of them had confirmed cancer, renal failure, cardiovascular pathologies, etc. [ 2 ]

The head of PEI's drug safety department confirmed that the deaths were not the result of vaccination. "When elderly patients or those with severe chronic pathologies are vaccinated (and this is where vaccination began), there is a possibility of a certain number of deaths that are not caused by vaccination."

By the way, in Germany vaccines from BioNTech/Pfizer and Moderna are still used. These drugs are recommended by PEI representatives as products with a very high level of safety.

Is it mandatory to get vaccinated against COVID-19?

Experts from the World Health Organization recommend vaccination to everyone who has no contraindications. Only in this case can we expect a complete blockade of the pandemic spread of coronavirus infection.

Of course, many people are frightened by the fact that new COVID-19 vaccines have been developed in an extremely short time. This is true, because it usually takes years to develop a new biopharmaceutical. Scientists explain that the high speed of vaccine development is due to the active cooperation of many highly qualified specialists who have thrown all their efforts into the fight against the pandemic. [ 3 ]

How are the current COVID-19 vaccines different?

Vaccines from BioNTech/Pfizer [ 4 ] and Moderna [ 5 ] include a partial genetic code of the coronavirus pathogen, its messenger RNA. That is, vaccination with such drugs does not involve the weakened pathogen entering the body, but forces cells to produce the spike protein present on the surface of the coronavirus and activate the immune response in the form of antibody formation.

The Astra Zeneca vaccine from Oxford University works in a different way, using a modified version of a common adenovirus that causes the disease in chimpanzees. The adenovirus has been injected with a fragment of the genetic code of the COVID-19 coronavirus.

RNA vaccines (BioNTech/Pfizer and Moderna) deliver not an antigen to the body, but only genetic information about it. After that, the antigen is expressed in the patient's cells. Preclinical trials of such vaccines are quite promising and successful, and the drug is produced entirely in vitro. The only difficulty is that this technology is new and raises many questions in terms of large-scale drug production.

Vector vaccines are based on viral vectors that display the spike protein on their surface and are inactivated before use. As a result, vectors become less dangerous, since they lose the ability to replicate even in conditions of weak patient immunity. [ 6 ]

Inactivated vaccines are produced by growing the virus in cell culture, followed by chemical deactivation. An example of an inactivated drug is CoronaVac. [ 7 ]

The BioNTech/Pfizer, Moderna and Astra Zeneca vaccines have been approved for use in the United States and the United Kingdom. Vaccinations have begun in Mexico and Costa Rica (with the BioNTech/Pfizer vaccine), while Brazil has authorized vaccinations with the Astra Zeneca vaccine and the Chinese product Sinovac.

For comparison, the table describes some of the most popular COVID-19 vaccines (according to information from British sources):

Moderna	Contains messenger RNA (a particle of the viral genetic code)	Two doses of the drug are required.	According to expert assessment, the efficiency is more than 94%	Storage for seven months at temperatures from -15 to -25°C
BioNTech/Pfizer	Contains RNA	Two doses of the drug are required.	The efficiency is 95%	Storage for six months at temperatures from -60 to -80°C
Oxford-Astra Zeneca	Contains a viral vector (genetically modified virus)	Two doses are required	According to expert assessment, the efficiency is more than 70%	Storage for six months at 2-8 °C
Sinovac (CoronaVac)	Contains a killed (weak) virus	Two doses are required	The reported efficiency ranges from 50 to 78%, but requires further expert evaluation.	Storage at temperatures from 2 to 8°C
Sputnik V	Contains a viral vector	Two doses of the drug are required.	The reported efficiency is over 91%, but requires further expert evaluation.	Storage at -18.5°C (in liquid state) or from 2 to 8°C (in dry state)

The CoronaVac vaccine, developed on the basis of a neutralized virus, was approved for use in China, Indonesia, Malaysia, Singapore, and the Philippines. However, this drug became less popular after independent studies demonstrated its insufficient effectiveness - about 50.4% (tests were conducted in Turkey, Brazil, and Indonesia).

India has approved the use of Bharat Biotech's indigenous biologic Covaxin, as well as Astra Zeneca (locally known as Covishield).

Russia uses its own vector drug Sputnik V, which has also been purchased by countries such as Argentina, Belarus, the United Arab Emirates, Hungary, Turkmenistan, Serbia, Palestine, Paraguay, and Venezuela.

African countries – members of the AU – have approved the use of vaccines from BioNTech/Pfizer, Astra Zeneca and Johnson&Johnson (the latter option is still in the testing stage).

When is the COVID-19 vaccine contraindicated?

A person who will be administered one of the COVID-19 vaccines should not have signs of acute respiratory viral infection or exacerbation of existing chronic pathologies. 5 days before the injection, you should not drink alcohol or overeat fatty foods.

If you have a runny nose, cough, high temperature, or general poor health, you should wait with vaccination. [ 8 ]

In addition to general contraindications, a person must be psychologically prepared for the procedure. Excessive stress, fear, and anxiety can lead to increased blood pressure and the production of stress hormones, which will negatively affect the cardiovascular system and may cause complications. [ 9 ]

If the patient is prone to allergic reactions, he/she should take an antihistamine the day before vaccination.

In order to prevent negative consequences, many experts recommend taking a PCR test before the procedure to rule out the latent course of COVID-19. It would also be useful to test for IgG and IgM antibodies, and after the vaccine is administered, to analyze the level of IgG antibodies. After vaccination, the development of immune protection does not occur immediately, but after about 2 weeks. [ 10 ]

At the beginning of 2021, scientists around the world were already working on two hundred potential drugs for vaccination against COVID-19. More than sixty vaccines have undergone clinical testing, and only six of them have received approval for use in different countries.