All about vaccination

Last updated on 24.08.2021

We can do it together!

There are more than 160 various types of COVID-19 vaccines being developed at the moment, while some of them have been used to combat some infectious disease in the past. Some of them are completely new and still awaiting approval.

1. USE OF RNA / mRNA VACCINES - (Moderna, Pfizer / BioNTech).

The vaccine, which was recommended by the European Medicines Agency shortly before Christmas and subsequently approved by the Slovak State Institute for Drug Control, is called Comirnaty (Pfizer/BioNTech). The vaccination by this vaccine has begun in the United Kingdom in early December. The United States has been vaccinating on the same basis since mid-December 2020. The Slovak Republic started vaccinating with Comirnaty shortly after Christmas.

PROCESS

This vaccine is based on the use of genetic information directly from the virus, inserted into the fat envelope, so RNA enters cells much easier. Should the envelope be not used, our body could automatically destroy the viral information as an intruder and the vaccine itself would not function. It means that not the whole virus but only one specific viral protein enters the body after vaccination. In the cytoplasm of a cell, RNA is then transcribed into a protein that is either produced on the surface of that cell or goes directly out of it. It is thus exposed to the immune system, which creates its reaction - the antibody response. Viral information does not come into contact at all with our DNA, which is found in the nucleus of the cell. Moreover, our cell destroys RNA after it is used.

RAPID DEVELOPMENT OF AN EFFECTIVE VACCINE

According to many experts, the RNA/mRNA vaccine is incomparable with other platforms, as the whole development process took only weeks. This meant that a clinical trial could be launched approximately after a month. Another advantage was the fact that some portfolios of companies that have entered the development against COVID-19 include many other vaccines based on the same principle in other applications mostly for infectious diseases. However, some of them are used to combat oncological diseases. It is important to note, that such type of a vaccine has not yet been approved for human use and therefore it is necessary to closely monitor all aspects resulting from clinical trials.

A large clinical trial proved 95 % effectiveness of Comirnaty vaccine against COVID-19 in people aged 16 and older. A total of approximately 44,000 people participated in the study.

2. USE OF VECTOR VACCINES (Chinese and Russian vaccine concept, ASTRA ZENECA in collaboration with Oxford University)

The Sputnik V vector vaccine was used in early December when Russia became the first country in the world to vaccinate its people.

From January 2021, the United Kingdom also began vaccinating residents with the AstraZeneca/Oxford University vaccine. Several companies have focused on the use of vector vaccines to fight against COVID-19.

Process

These vaccines are based on a very simple principle - not a real virus, but a safe virus which does not cause the disease is in this case used for carrying the protein. Thus, it cannot cause the disease and yet, the immune system is very effectively stimulated. Carriers for this purpose are based on various types of safe viruses and can cause a common mild cold after vaccination or remain asymptomatic.

RAPID DEVELOPMENT OF AN EFFECTIVE VACCINE?

USE OF LIVE VIRUSES - (being developed)

This case represents the use of attenuated or dead viruses. The manufacturing process and approval procedures for this type of vaccines take longer.

USE OF RECOMBINANTS - (being developed)

This approach to vaccine production is based on the fact that the proteins of a given virus are produced in purely laboratory conditions and not obtained directly from the virus.

USE OF SUB-UNIT VACCINES - (being developed)

Larger parts of proteins are used to produce a vaccine in this case. They serve as immunogens. This method has been proven and used, e.g., for influenza vaccines.

COVID-19 has accelerated the technological process used for development of new types of vaccines, which may be a great advantage for the future of vaccines as such. The classical approaches and older concepts could be replaced by new technologies in the future. Consequently, this could gradually reduce the amount of side effects which, of course, may occur as in any other medicine.

 

Following recommendation of the European Medicines Agency, the European Commission granted a conditional marketing authorization for Comirnaty (from Pfizer/BioNTech) against COVID-19 on 21 December 2020.

What does "conditional marketing authorization" mean?

Should an emergency situation concerning public health occur, a drug or vaccine can be granted a conditional marketing authorization.

This would occur when the benefits of immediate provision outweigh the risk of producing fewer comprehensive data then would be required in normal conditions. In such cases, the producer undertakes to supply additional data in accordance with within the set schedule.

Anyway, the European Commission will grant a marketing authorization only if assessment of European Medicines Agency proves that the vaccine is both, safe and effective.

IS THE COMIRNATY VACCINE FROM Pfizer/BioNTech SAFE?

The COVID-19 vaccine Moderna offers a high level of protection against COVID-19 in the current pandemic. Extensive clinical trials have proved the vaccine to be 94.1 % effective.

The side effects of Comirnata were ranged from mild to moderate in intensity and declined within few days after vaccination.

The European Medicines Agency has therefore decided that the benefits of Comirnaty outweigh the risks associated with its use and has recommended it to be authorized in the EU.

As Comirnaty has been granted a marketing authorization under the condition that the producer shall continue to provide results of the main trial to be carried out for next two years. This trial as well as other studies shall provide data on the duration of protection, the reliability of the vaccine in prevention of severe course of COVID-19, the reliability in protection of people with compromised immunological response as well as children and pregnant women. It shall also provide information whether the vaccine prevents asymptomatic course of the disease. In addition, independent studies of COVID-19 vaccines coordinated by EU authorities will provide more information on the long-term safety and benefits of the vaccine for general population.

IS THE COMIRNATY VACCINE FROM Pfizer/BioNTech EFFECTIVE?

Extensive clinical trials in approximately 44,000 volunteers have demonstrated the effectiveness of Comirnaty in humans over 16 years of age.

Its effectiveness has been evaluated in approximately 36,000 people aged more than 16 (including people over 75 years of age) who did not have symptoms of previous infection. The study proved a 95 % reduction in symptomatic cases of COVID-19 in people who received the vaccine (8 out of 18,198 had symptoms of COVID-19) compared with those who received placebo injections (162 out of 18, 325 patients had COVID-19 symptoms)

In a clinical trial, 95 % effectiveness has been proved even in people who were in the risk of severe COVID-19 such as asthmatics, people with chronic lung diseases, diabetes, high blood pressure or body mass index of ≥ 30 kg/m2.

HOW MANY TIMES DO I NEED TO BE VACCINATED?

According to the package leaflet, Comirnaty vaccine from Pfizer/BioNTech is given in two doses to the arm at an interval of at least 21 days. The Government of the Slovak Republic has issued a decree in compliance with this summary of characteristics the vaccine and the second dose of Comirnaty shall be administered at intervals of at least 28 days in Slovakia.

Should you not be able to attend the 2nd dose of the vaccine, please, discuss the next steps with your doctor and ask for an alternative date. Should you not be administered any vaccine, you may not be completely protected against COVID-19.

IS IT NECESSARY TO BE VACCINATED BY COMIRNATY VACCINE EVERY YEAR?

It is currently unknown how long the protection lasts after vaccination with Comirnata. Subjects vaccinated in the clinical trial will be followed up for 2 years to obtain more data on the duration of protection.

IN WHICH CASES SHOULD I NOT BE VACCINATED WITH CORMINATY?

  • Children

Comirnaty is not recommended for children under 12. European Medicines Agency (EMA) and the producer of Comirnaty have drawn up a plan to test the vaccine in children in future.

  • Pregnant and breastfeeding women

Animal studies have not shown any harmful effects during pregnancy, but there are very few data from the use of Comirnaty during pregnancy. The decision to undergo vaccination during pregnancy should be made on the basis of detailed consultation with medical professionals and consideration of benefits and risks.

  • Other medicines and Comirnaty

In case you use, have recently been using any other medicines or have been administered any other vaccine, please, inform your doctor.

  • People with compromised immune response

There is limited evidence of people with a compromised immune response. Although people with impaired immune system do not respond to the vaccine so well, there are no safety concerns related to its use. People with compromised immunity can also be vaccinated as they are at greater risk of developing COVID-19.

  • Allergies

People who know that they are allergic to one of the components contained in the vaccine mentioned in the section 6 of the package leaflet should not be administered this vaccine. Allergic reactions (hypersensitivity reactions) have been observed in people vaccinated with this vaccine. There have been a very small number of cases of anaphylaxis (a severe allergic reaction) since the vaccine was used in vaccination campaigns. Like all vaccines, Comirnaty should only be administered under strict medical supervision and with appropriate medical equipment available. Should a person develop a severe allergic reaction after receiving the first dose of Comirnaty, the second dose should not be administered.

WHAT SIDE EFFECTS MAY OCCUR AFTER VACCINATION BY CORMINATY BY Pfizer/BioNTech?

Like all medicines, this vaccine can also cause side effects, although not everybody will experience them. The most common side effects caused by Corminaty vaccine usually ranged from mild to moderate in severity and improved within few days after vaccination.

If you experience any side effects, please, talk to your doctor, pharmacist, or nurse. Even side effects not listed in the leaflet to Comirnaty vaccine should be discussed.

These may include the following:

Very frequent (may affect more than 1 in 10 people): Pain and swelling at the injection site, tiredness, headache, muscle pain, joint pain, chills, fever

Frequent (may affect less than 1 in 10 people): redness at the injection site, nausea.

Less frequent (may affect less than 1 in 100 people): enlarged lymph nodes, uncomfortable feelings, pain in limbs, insomnia, itching at the injection site

Rare (may affect less than 1 in 1,000 people) temporal unilateral facial paralysis

Not known (according to available data): severe allergic reaction

(read the package leaflet for Comirnaty vaccine issued by Pfizer/BioNTech)

HOW THE COMIRNATY VACCINE WORKS

Comirnaty vaccine works on the principle of mRNA, which is simply the carrier of a genetic instruction. Even simpler, it is a guide to show our body how to create one part of the virus. Specifically, it creates the characteristic protrusion of the coronavirus that you see in each of its graphic depictions or illustrations. This protrusion is called the spike protein and is located on the coronavirus envelope, which is why the virus is able to enter human cells.

Thanks to this guide found in the mRNA vaccine, our body is able to produce this part of the virus. The immune system then recognizes it as a foreign element in our body and triggers a defence reaction - begins to form antibodies and T-cells. As a result of such "training" received by our body, we shall become resistant to real corona virus.

Vaccines based on mRNA principle represent a new type of vaccines, which is perhaps one of the reasons why some people are concerned about this technology. However, mRNA vaccines are not entirely new, in fact they have been studied for several years in relation to other diseases and have been used repeatedly in clinical trials.

COVID-19 vaccine Moderna

Following recommendations by the European Medicines Agency, the European Commission granted a conditional marketing authorization for COVID-19 - Moderna vaccine against COVID-19 in early January (January 6th, 2021).

What does "conditional marketing authorization" mean?

Should an emergency situation concerning public health occur, a drug or vaccine can be granted a conditional marketing authorization.

This would occur when the benefits of immediate provision outweigh the risk of producing fewer comprehensive data then would be required in normal conditions. In such cases, the producer undertakes to supply additional data in accordance with within the set schedule.

Anyway, the European Commission will grant a marketing authorization only if assessment of European Medicines Agency proves that the vaccine is both, safe and effective.

IS COVID-19 VACCINE MODERNA SAFE?

The COVID-19 vaccine Moderna offers a high level of protection against COVID-19 in the current pandemic situation. Extensive clinical trials have proved the vaccine to be 94.1 % effective. Severity of side effects caused by COVID-19 Moderna ranged usually from mild to moderate and improved within few days after vaccination.

The European Medicines Agency has therefore decided that the benefit of COVID-19 Vaccine outweighs the risks associated with its use and recommended it for marketing authorization in the EU.

Data concerning the use of COVID-19 vaccine Moderna are continuously being monitored, as it is with other drugs and vaccines. Reports of suspected side effects caused by a vaccine are being carefully evaluated and all necessary measures to protect patients have been taken.

As COVID-19 vaccine Moderna has received conditional marketing authorization, the producer of the vaccine will continuously provide results of clinical trials for the next two years. This and other studies will provide even more precise information on the duration of protection after vaccination, on the prevention of severe forms of COVID-19, or how to protect people with compromised immune system, children, or pregnant women.

In addition, independent studies of COVID-19 vaccines coordinated by EU authorities will provide more information on the long-term safety and benefits of the vaccine for general population.

Is COVID-19 Moderna vaccine effective?

Extensive clinical trials including almost 30,000 volunteers have proved the effectiveness of COVID-19 Moderna in adults aged 18 and older.

The study proved a 94.1 % reduction in the number of symptomatic cases of COVID-19 in people who received the vaccine (11 out of 14,134 vaccinated people suffered symptomatic COVID-19) in comparison with people who were administered sham injections (185 out of 14,073 suffered symptomatic COVID-19).

The study also proved 90.9 % effectiveness in participants in the risk of developing severe form of COVID-19 including patients with chronic lung diseases, heart diseases, obesity, liver diseases, diabetes, or HIV infection.

HOW MANY TIMES DO I NEED TO BE VACCINATED?

COVID-19 vaccine Moderna is administered in two injections into an arm in the interval of 28 days.

Should it be impossible for you to attend the 2nd dose of the COVID-19 vaccine Moderna, please, make another appointment with your doctor as soon as possible. Should you not be administered any vaccine, you may not be completely protected against COVID-19.

DO I NEED TO BE VACCINATED BY COVID-19 VACCINE MODERNA EVERY YEAR?

It is currently unknown how long the protection by COVID-19 vaccine Moderna lasts. People vaccinated in a clinical trial will be further examined for 2 years to obtain more information on the length of protection.

IN WHICH CASES SHOULD I NOT BE VACCINATED TO COVID-19 MODERN VACCINE?

  • Children

COVID-19 Moderna is not recommended for children and adolescents under 18. The European Medicines Agency and the vaccine producer plan to test the vaccine in children in the future.

  • Pregnant and breastfeeding women

Animal studies do not indicate any harmful effects during pregnancy. However, data on the use of COVID-19 Moderna during pregnancy are limited. If you are pregnant or breastfeed, think you may be pregnant or planning to get pregnant, please, consult the administration of the vaccine with your doctor, pharmaceutics, or nurse.

  • Other medicines and COVID-19 vaccine Moderna

If you take or have recently taken or might take any medicines in future, please, inform your doctor or pharmacist of the fact. COVID-19 vaccine Moderna may affect the way other medicines work and other medicines may affect the way COVID-19 vaccine Moderna works.

  • People with compromised immune response

Currently available data concerning people with compromised immune responses are limited. Although people with a compromised immune system may not respond well to the vaccine, there are no particular safety concerns. People with weakened immunity can also be vaccinated as they are at greater risk of developing COVID-19.

  • Allergies

People who know they are allergic to some kind of drug or any component contained in Moderna, should not be administered this vaccine.

Allergic reactions (hypersensitivity) have been observed in people receiving the vaccine. There have been very few cases of anaphylaxis (a severe allergic reaction). Therefore, as with all vaccines, COVID-19 vaccine Moderna should be administered under strict medical supervision and appropriate medical treatment should be available in case of allergic reactions. People with severe allergic reaction after the administration of the first dose of COVID-19 vaccine Moderna should not be administered the second dose.

WHAT SIDE EFFECTS MAY OCCUR AFTER VACCINATION BY COVID-19 VACCINE MODERNA?

Like all medicines, this vaccine can also cause side effects, although not everybody will experience them. Severity of COVID-19 Moderna side effects ranged usually from mild to moderate and improved within few days after vaccination.

Please, seek immediate medical assistance if any of the following symptoms of allergic reaction occurs: faintness or dizziness, changes in heart rhythm, shortness of breath, wheezing, swelling of lips, face or throat, hives or rash, nausea or vomiting, stomach pain.

Should you experience any side effects, please talk to your doctor or nurse. These may include the following:

Very frequent (may affect more than 1 in 10 people): swelling in the armpits, headache, nausea, vomiting, muscle and joint pain and stiffness, pain or swelling at the injection site, feeling very tired, chills, fever.

Frequent (may affect less than 1 in 10 people): rash, redness or hives at the injection site.

Less frequent (may affect less than 1 in 100 people): itching at the injection site.

Rare (may affect less than 1 in 1,000 people) temporary unilateral facial paralysis (Bell's palsy), swelling of the face (swelling may occur in patients who have received cosmetic injections into the face).

Unknown frequency - severe allergic reactions (anaphylaxis), hypersensitivity.

Allergic reactions have occurred in people who have been administered the vaccine, including a very small number of cases of severe allergic reactions (anaphylaxis). Like all vaccines, COVID-19 Moderna should be administered under close medical supervision and with appropriate treatment.

(please, read the vaccine package leaflet issued by Moderna)

 

HOW COVID-19 MODERN VACCINE WORKS

The COVID-19 vaccine MODERNA works on the principle of mRNA, which is, in simple words, the carrier of a genetic instruction. Even simpler, it is a guide to show our body how to create one part of the virus. Specifically, it creates the characteristic protrusion of the coronavirus that you see in each of its graphic depictions or illustrations. This protrusion is called the spike protein and is located on the coronavirus envelope, which is why the virus is able to enter human cells.

Thanks to this guide found in the mRNA vaccine, our body is able to produce this part of the virus. The immune system then recognizes it as a foreign element in our body and triggers a defence reaction - begins to form antibodies and T-cells. As a result of such "training" received by our body, we shall become resistant to real corona virus.

Vaccines based on mRNA principle represent a new type of vaccines, which is perhaps one of the reasons why some people are concerned about this technology. However, mRNA vaccines are not entirely new, in fact they have been studied for several years in relation to other diseases and have been used repeatedly in clinical trials.

Following recommendations by the European Medicines Agency, the European Commission has already granted a conditional marketing authorization for the third COVID-19 - vaccine by AstraZeneca on 29 January 2021.

COVID-19 Vaccine AstraZeneca is used as protection against COVID-19 caused by the SARS-CoV-2 virus. It is administered to adults aged 18 and older. The vaccine makes the immune system (the body's natural protection) produce antibodies and specialized white blood cells that act against the virus and thus provides protection against COVID-19. None of the components of this vaccine is able to induce COVID-19 disease.

 

WHAT DOES "CONDITIONAL MARKETING AUTHORIZATION MEAN"?

Should an emergency situation concerning public health occur, a drug or vaccine can be granted a conditional marketing authorization.

This happens when the benefits of immediate provision of these vaccines outweigh the risk to use the drug with less comprehensive data available than is normally required. In such cases, the producer undertakes to supply additional information in accordance with the set schedule.

In any case, the European Commission will only grant a marketing authorization after the European Medicines Agency's assessment proves that the vaccine is both, safe and effective.

Because the AstraZeneca vaccine has been recommended for conditional marketing authorization, the company that introduces the COVID-19 vaccine AstraZeneca will continue to provide results from ongoing clinical trials.

 

WHY HAS THE EUROPEAN MEDICINES AGENCY RECOMMENDED TO GRANT AUTHORIZATION FOR THE VACCINE PRODUCED BY ASTRAZENECA?

COVID-19 Vaccine AstraZeneca offers a good level of protection against COVID-19. The most important studies have shown that the vaccine reaches the effectiveness of approximately 60 %. Most side effects range from mild to moderate in severity and pass within few days.

These are the reasons why the European Medicines Agency has decided that the benefits of the vaccine by AstraZeneca outweigh its risks and so it can be recommended for registration in the EU.

WHAT MEASURES HAVE BEEN TAKEN IN RELATION TO THE SAFETY AND EFFECTIVENESS OF THE VACCINE?

As in other cases, safety measures have been implemented for the AstraZeneca vaccine in accordance with the EU COVID-19 vaccine safety monitoring plan aiming in rapid collection and analysis of new safety information.

The company marketing COVID-19 Vaccine AstraZeneca will provide safety reports on monthly basis. As with all medicines, data on the use of COVID-19 AstraZeneca are constantly being monitored. Suspected side effects reported in relation to this vaccine should be carefully evaluated and all necessary measures taken to protect patients.

HOW DOES COVID-19 ASTRAZENECA WORK?

COVID-19 Vaccine AstraZeneca prepares the body to protect itself against COVID-19. It contains another virus (adenovirus) that has been engineered to include the SARS-CoV-2 spike protein gene. This protein on the surface of the SARS-CoV-2 virus needs to enter the cells of the body.

The vaccine delivers SARS-CoV-2 gene into cells after the administration. Cells use this gene to produce a spike protein. The human immune system then recognizes this protein as a foreign agent and produces antibodies and activates T cells (white blood cells) to attack the protein.

If a person comes into contact with the SARS-CoV-2 virus in future, their immune system will be able to recognize it and defend itself against it.

The adenovirus in the vaccine cannot multiply and does not cause the disease.

IN WHICH CASES SHOULD I NOT BE VACCINATED BY COVID-19 VACCINE ASTRAZENECA?

The vaccine must not be administered: - if you are allergic to the drug or to any of the other ingredients contained in the vaccine.

PLEASE NOTE:

Contact your doctor before COVID-19 Vaccine AstraZeneca is administered to you. In case you have ever had a severe allergic reaction after administration of any other vaccine or after receiving COVID-19 Vaccine AstraZeneca. In case you have ever fainted after having a needle injection. If you have a severe infection with a high temperature (over 38°C).

However, it is possible to get vaccinated you if you have a mild fever or an upper respiratory tract infection such as cold. If you have a problem with bleeding or bruising, or if you take any anticoagulant (a drug to prevent development of blood clots). If your immune system does not work properly (immunodeficiency) or you take medicines to weaken the immune system (such as high doses of corticosteroids, immunosuppressants or anticancer medicines). Provided that you are not sure if any of the above-mentioned cases apply to you, please, talk to your doctor before you are administered the vaccine.

As with any other vaccine, the 2nd dose of COVID-19 Vaccine AstraZeneca may not fully protect all the people who have been vaccinated. Duration of protection is not yet known. Data on the effectiveness of the COVID-19 Vaccine AstraZeneca in people aged 55 and older are currently limited.

CHILDREN AND ADOLESCENTS

COVID-19 Vaccine AstraZeneca is not recommended for children under 18. Information on the use of COVID-19 Vaccine AstraZeneca in children and adolescents under 18 is currently insufficient.

OTHER MEDICINAL PRODUCTS AND COVID-19 VACCINE ASTRAZENECA

If you take or have recently been taking or may be taking any other medicines, or have been administered any other vaccine, please, inform your doctor or pharmacist.

PREGNANCY AND BREASTFEEDING

If you are pregnant or breastfeed, think you may be pregnant or planning to get pregnant, please, consult the administration of the vaccine with your doctor, pharmacist or nurse.

WHAT ARE THE BENEFITS OF COVID-19 ASTRAZENECA PROVED BY STUDIES?

Combined results acquired by 4 clinical studies in the United Kingdom, Brazil and South Africa proved that COVID-19 AstraZeneca was safe and effective in preventing COVID-19 in people aged 18 and older. These studies involved approximately 24,000 people. Half of the subject received the vaccine and the other half received sham injections.

The Agency based its calculation of the effectiveness on the results acquired in the study COV002 (performed in the UK) and study COV003 (performed in Brazil). There were less than 6 cases of COVID-19 reported in the other two studies and it was not enough to measure the preventive effect of the vaccine. The vaccine is to be administered in two standard doses and the second dose is to be given between 4 and 12 weeks after the first injection. The agency therefore focused on the results concerning people on this standard schedule.

The results showed a 59.5 % reduction in the number of symptomatic cases of COVID-19 in people who received the vaccine (64 out of 5,258 people suffered COVID-19 with symptoms) compared with people who received sham injections (154 out of 5,210 COVID-19 with symptoms). This means that the vaccine has shown approximately 60 % effectiveness in clinical trials.

Most participants in these studies aged from 18 to 55. There were insufficient results in elderly participants (over 55 years of age) to see how well the vaccine would work in this group. However, scientists from the European Medicines Agency have concluded that the vaccine can be used by older adults regarding their immune response and experience with other vaccines and their safety within population. It is expected, that currently ongoing studies with higher proportion of older participants shall provide more information.

HOW IS COVID-19 VACCINE ASTRAZENECA ADMINISTERED?

COVID-19 Vaccine AstraZeneca is administered as an injection into a muscle (usually in the shoulder). During and after each injection of the vaccine, your doctor or nurse will monitor you for about 15 minutes to see whether you are developing any allergic reaction.

You will receive 2 doses of COVID-19 Vaccine AstraZeneca. The second injection may be administered from 4 to 12 weeks after the first dose.

Should it be impossible for you to attend the administration of the 2nd dose of COVID-19 Vaccine AstraZeneca, please, make another appointment with your doctor or nurse as soon as possible. Should you not attend both scheduled administrations, you may not be completely protected against COVID-19.

POTENTIAL SIDE EFFECTS OF COVID-19 VACCINE ASTRAZENECA

Like any other medicine, this vaccine may cause side effects, although not everybody experiences them.

Please, seek immediate medical assistance if any of the following symptoms of allergic reaction occurs: faintness or dizziness, changes in heart rhythm, shortness of breath, wheezing, swelling of the lips, face or throat, hives or rash, nausea or vomiting, stomach pain.

The following side effects may occur with COVID-19 Vaccine AstraZeneca:

Very frequent (may affect more than 1 in 10 people) - tenderness, pain, heat, itching or bruising at the injection site, - feeling tired (tired) or feeling generally unwell, - chills or fever, - headache, - feeling sick (nausea), - joint or muscle pain.

Frequent (may affect less than 1 in 10 people) - swelling or redness at the injection site, - fever (> 38 ° C), - nausea (vomiting) or diarrhoea.>

Less frequent (may affect less than 1 in 100 people) - drowsiness or dizziness, - decreased appetite, - enlarged lymph nodes, - excessive sweating, itchy skin, or a rash.

(please, read the vaccine package leaflet for  COVID-19 Vaccine AstraZeneca)

 

mRNA is simply the carrier of a genetic instruction. Even simpler, it is a guide to show our body how to create one part of the virus. Specifically, it creates the characteristic protrusion of the coronavirus that you see in each of its graphic depictions or illustrations. This protrusion is called the spike protein and is located on the coronavirus envelope, which is why the virus is able to enter human cells.

Thanks to this guide found in the mRNA vaccine, our body is able to produce this part of the virus. The immune system then recognizes it as a foreign element in our body and triggers a defence reaction - begins to form antibodies and T-cells. As a result of such "training" received by our body, we shall become resistant to real corona virus.

Vaccines based on mRNA principle represent a new type of vaccines, which is perhaps one of the reasons why some people are concerned about this technology. However, mRNA vaccines are not entirely new, in fact they have been studied for several years in relation to other diseases and have been used repeatedly in clinical trials.

Vaccines from Pfizer/BioNTech and Moderna, which have already been registered in the EU, are also based on the mRNA principle. The registration of the COVID-19 vaccine in the European Union guarantees that the vaccine meets the same high standards of safety, quality and effectiveness. It is confirmed in vaccination practice being performed in many countries around the world.

It is typical for viruses to mutate over time, while mutations take place at different rate. However, mutations in general does not necessarily affect effectiveness of vaccines.

Experts and regulatory authorities closely monitor how the virus COVID-19 changes over the time and how can COVID-19 vaccines cope and protect people against newly emerging variants of the virus.

MEASLES AND RUBELLA Vaccines against some viral diseases (such as measles or rubella) developed in the past remain just as effective today and provide long-term protection.

INFLUENZA

Vaccines against other viral diseases (such as influenza) need to be updated every year, because the influenza virus in particular mutates frequently and extensively. New variants of influenza virus need to be responded to by a new effective vaccine each flu season.

The effectiveness of a vaccine is determined by its ability to prevent a disease. Properly administered, they help protect the population against diseases.

As with other medicines, the vaccine is not 100 % effective in every individual.

The effectiveness is individual and depends on several factors. For example:

age of the person,

consumption of other medical products or existing diseases,

time after vaccination,

previous contact with the pathogen of the disease,

method used for administration of the vaccine,

the vaccine itself.

For example, prevention of measles, mumps and rubella by MMR vaccine is extremely effective in prevention of these diseases. It provides lifelong protection and its effectiveness ranges from 97 to 99 % in healthy children who receive two doses.

However, in certain circumstances, an individual may develop the disease, although the recommended number of doses has been administered. The reason is, that the individual is unable to create a sufficient protection against the disease or their immune systems weakens over the time. Nevertheless, the course of the disease in these people is milder than in people without vaccination. Moreover, it reduces the likelihood of infecting others.

Research and development of vaccines is carried out in several characteristic steps, which are also typical in research and development of other drugs. It could not have been otherwise even in the case of the COVID-19 vaccine. Vaccine development is a rather complex process. The most crucial is to identify the component which should activate an immunological response. In order to make the vaccine effective, stable and safe, it is necessary to determine which adjuvants it should contain and in what quantity.

Research and development of vaccines in individual steps

PRE-CLINICAL PHASE - Like all medicines, vaccines are first tested in a laboratory.

The development of each vaccine will initially go through the in vitro research phase and then the in vivo animal research stage.

CLINICAL TRIAL - helps confirm how vaccines work and ensure that their benefits outweigh any side effects or risks.

In the next step, the vaccines are tested in several rounds on human volunteers. The first round examines how much vaccine (so-called antigen) is needed to activate a sufficient immunological response and still keep the vaccine safe. In the second and third phase, randomized double-blind experiments take place. The volunteers are randomly divided (usually lots are drawn) into a group that receives the test vaccine and a group that receives the inactive substance (placebo). Neither volunteers do not know which of the two alternatives they receive or administer. After administration of both substances in both groups, the parameters are evaluated - how the organism reacted to the vaccine and whether it produced a sufficient amount of antibodies, whether or what adverse effects occurred after vaccination. In this step it is also possible to determine how many doses are needed for vaccination in order to protect the person adequately.

The company developing the vaccine cannot carry out clinical trials without provision of information, approval and supervision of drug agencies or administer an unregistered medicine to patients. It is essential to protect the rights and health of participants in the research concerning drugs and vaccines. Therefore, a producer of vaccines must obtain the consent of an independent authority - the ethics committee.

REGISTRATION - decision to use a vaccine for the general public in large quantities

As soon as sufficient research data and data from clinical trials are available, companies may apply to one of medicines agencies for marketing authorization.

It is not an easy process, medical authorities asked to provide the authorization must follow each stage of the process in great detail. All the results must be available for them so they may base their decision on them and decide whether the vaccine shall be registered or not.

PLACING OF VACCINES AT THE EU MARKET

Should the vaccine producer apply for marketing authorization by the European Medicines Agency, the European Commission shall grant a marketing authorization within the EU under the condition that the assessment provided by the agency proves that the vaccine is both, safe and effective. A drug or vaccine may also be granted a conditional marketing authorization in case of an emergency situation in the field of public health. This would occur when the benefits of immediate provision outweigh the risk of producing fewer comprehensive data then would be required in normal conditions. In such cases, the producer undertakes to supply additional data in accordance with within the set schedule.

Monitoring of vaccines does not end after they are registered. It continues during the time when they are widely used by the public. Side effects or the effectiveness of the vaccines are continuously being monitored.

Following the authorization of the vaccine, the national authorities of the EU/EEA Member States and the European Medicines Agency (EMA) continuously monitor side effects in people who have been vaccinated.

Such procedure enables immediate detection of all risks that may occur.

The European Medicines Agency checks all information concerning safety of vaccines in Europe. It analyses a large number of data sources, including the following:

reports from patients, parents, and healthcare professionals,

clinical studies,

specialized medical literature,

information used by other regulatory authorities.

The EMA carefully assesses suspected side effects to determine whether there is a link to the vaccine. Thus, it is possible to exclude the possibility that the given case was an accident, or the consequence of factors unrelated to the vaccination. Side effects may sometimes manifest other diseases or fear from vaccination.

Should it be necessary, the European Medicines Agency in cooperation with the European regulatory authorities shall take the inevitable measures. These may include, e.g., drawing up of updated guidelines for healthcare professionals or even restrict the use of the given vaccine for some groups of people.

Patients, healthcare professionals and pharmaceutical companies should report any suspected side effects to national medicines agencies. For more information on how to report suspected side effects, please, see the information on the prescription of the medicine or in the written information for a patient.

See also: How and where to report potential side effects after vaccination?

Viruses and bacteria elicit a unique immune system response in each individual, involving a particular type of cell in the blood, bone marrow, and whole body, such as T cells, B cells, and others.

The vaccine stimulates an immune response. The body thus "remembers" the disease without developing it.

Vaccines contain highly attenuated or inactivated (killed) forms of viruses or bacteria or small parts of viruses or bacteria which may cause the disease. They are called antigens.

Should a person receive a vaccine, their immune system will recognize the antigen as a foreign element. Immune cells are focused on killing disease-causing substances and produce antibodies. Antibodies are special proteins that help kill infectious substances.

Should a person come into contact with a virus or bacterium later, their immune system will remember this pathogen. The production of right antibodies begins quickly, and appropriate immune cells are activated, so the virus or the bacterium is killed and the person is thus protected from the disease.

Immunity usually lasts for years and sometimes a lifetime. It depends on the type of disease and the vaccine.

Immunity acquired by vaccination protects not only immunized individuals, but also unvaccinated people in the community, such as children who are too young to be vaccinated. This collective immunity can only be effective if a sufficient number of people is vaccinated.

On the other hand, should an individual acquire immunity by overcoming a disease, other unvaccinated people may be exposed to the infection. Even such person is in the risk of developing complications.

Vaccination protects vaccinated people as well as their close relatives who are prone to diseases, reduce the risk of the spread of diseases among family members, classmates or colleagues, friends, neighbours, and other people within communities.

Should there be a sufficient number of individuals in the community immune to a contagious disease, it is unlikely that the disease would be transmitted from one person to another. This is called population immunity (also known as collective immunity).

Should there be a sufficient number of people within the community immune to an infectious disease, the collective immunity develops.

Vaccines thus indirectly protect people who are prone to contract the disease. They include young children, the elderly, people with a compromised immunological response, oncological patients and people who cannot be vaccinated for health reasons.

It means, that individual who cannot be vaccinated because of their young age or allergies to some component of the vaccine are protected thanks to vaccination of others. Diseases just cannot spread so easily.

For example, to ensure the immunity of the population against measles, public health authorities recommend having 95 % of population vaccinated by two doses of the measles vaccine (MMR vaccine, which provides protection against measles, mumps, and rubella).

However, collective immunity cannot protect individuals from certain infectious diseases anyway. For example, tetanus can occur as a result of an injury, dog or cat bites. Protection against tetanus can only be ensured by vaccination.

Moreover, immunization programs contribute to lessening of social, psychological, and financial burden that diseases place on the population and public administration. They also reduce pressure on health care and social care and thus enable people to participate actively on educational and employment processes.

Vaccines protect hundreds of millions of people around the world from serious diseases every year. Vaccines prevent diseases that could otherwise cause serious health problems, permanent disability or even death.

Unlike drugs to treat the disease, vaccines are usually given to healthy people to prevent the disease. Therefore, the long-term benefits of vaccination may not be obvious at the first sight.

Thanks to vaccination, many infectious diseases are currently so very rare that their negative consequences are sometimes forgotten. Should people stop vaccinations, many of these diseases could re-emerge and cause epidemics.

Example no. 1: measles

Measles have been almost wiped out in many European countries.

Outbreaks of measles have been reported in the EU/EEA since October 2016, while epidemics also occurred due to declining vaccination rates in several countries (2).

Measles can be a serious and even a life-threatening disease. (For more information, see the measles fact sheet.)

Vaccination is the only protection against measles. The MMR vaccine protects against measles, mumps, and rubella. The MMR vaccine is safe and effective.

Example no. 2: whooping cough

Whooping cough (pertussis) is a disease affecting air passages. It spreads quickly. It often leads to hospitalization of infants, with a higher risk of complications and hospitalization of children under 3 months. Pertussis can cause severe bouts of coughing and usually lasts from three to six weeks.

Complications include pneumonia, encephalopathy (brain disease), seizures and even death. (For more information, see the whooping cough report.)

Vaccination against whooping cough is included in national immunization programs of EU countries. It protects children from whooping cough and the disease causes only less significant side effects. Approximately 20% of infants experience redness and pain at the injection site. Less than 5 % develop fever.