The AstraZeneca vaccine is another COVID-19 vaccine that has been marketed in the European Union. Various groups of people, including teachers, will be vaccinated with AstraZeneca in Poland. How does AstraZeneca work and is it effective? What is its composition? Is AstraZeneca safe? What are the complications of AstraZeneca?
The AstraZenecavaccine is the third vaccine against coronavirus, after the Pfizer BioNTech and Moderna vaccine, which Poles are vaccinated with. Its full name is COVID-19 Vaccine AstraZeneca. Poland has so far ordered 16 million doses of this vaccine.
People aged 18-60 are to be vaccinated in Poland with AstraZeneca. The first group of people vaccinated with this vaccine are teachers. Vaccination of this professional group has caused a lot of controversy, and people vaccinated with AstraZeneca complain of severe complications, including fever and flu-like symptoms.
What is known about AstraZeneca? What information is in the Summary of Product Characteristics and Package Leaflet?
AstraZeneca vaccine - composition and mode of action
AstraZenecais a monovalent vaccine that is administered intramuscularly. It is not an mRNA vaccine, but a vector vaccine. It contains a single, recombinant and replication-defective vector for adenovirus (not coronavirus).
After vaccination, local synthesis of S-glycoprotein takes place (the S protein is also found on the surface of the SARS-CoV-2 coronavirus and is needed for it to enter the body). The immunized person's immune system recognizes this protein as an intruder, which stimulates the immune response and produces antibodies that neutralize the coronavirus. When a vaccinated person comes into contact with the SARS-CoV-2 coronavirus, their immune system will be prepared for it.
Sodium is listed among the excipients to AstraZeneca - however, since there is less than 1mmol sodium (23mg) per 0.5ml dose, this product is considered "sodium-free". There is also a small amount of ethanol in the composition - 2 mg in a dose of 0.5 ml. As the manufacturer assures, suchthe amount of alcohol has no noticeable effect.
AstraZeneca vaccine - dosage and administration
AstraZenecais intended for people over 18 years of age. In Poland, it is to be awarded to people aged 18-60. The vaccination cycle consists of two doses - 0.5 ml of the preparation each. The second dose should be given between 4 and 12 weeks after the first dose, i.e. 28 to 84 days.
There is currently no data on whether the second dose of AstraZeneca can be replaced with another COVID-19 vaccine. The Summary of Product Characteristics states that persons vaccinated with the first dose of AstraZeneca for the full course of vaccination should also receive a second dose of AstraZeneca.
AstraZeneca vaccine - contraindications and restrictions
The contraindication to vaccination with AstraZeneca is hypersensitivity to the active substance or to any of the excipients.
After vaccination, observation for at least 15 minutes is recommended in order to exclude an anaphylactic reaction. A second dose of the vaccine should not be administered if this reaction occurs.
Vaccination should be postponed in people suffering from an acute (febrile) infection or acute infection. Mild infections such as a cold or a mild fever are not contraindications for vaccination.
The vaccine - as with other intramuscular injections - should be carefully administered to people with thrombocytopenia or other bleeding disorders or receiving anticoagulant treatment because of possible bleeding or bruising.
AstraZeneca vaccine - possible complications after vaccination
According to the data provided by the manufacturer, the most commonly reported adverse reactions following administration of AstraZeneca are:
- injection site tenderness (63.7%)
- injection site pain (54.2%)
- headache (52.6%)
- fatigue (53.1%)
- muscle pain (44.0%)
- malaise (44.2%)
- fever (33.6%), fever>38 degrees C (7.9%)
- chills (31.9%)
- joint pain (26.4%)
- nausea (21.9%).
Most of these side effects were mild to moderate and usually wear off after a few days. Side effects were less frequent and milder after the second dose of the vaccine.
The side effects of AstraZenecaare worrying - but experts from the Science Against Pandemic initiative point out that it is completely unjustified. The statement they released read: "Immunization on the roadvaccination may be associated with the appearance of temporary symptoms of varying severity.
This phenomenon is commonly seen in vaccines, is not a cause for concern, and is related to the effects of these preparations that are specifically designed to stimulate immune cells. "
Experts from the Science Against Pandemic initiative also write that: "Fever and muscle pain after administration of AstraZeneki is more often observed than in the case of vaccination with mRNA preparation, while soreness in the arm is less frequent. These symptoms are temporary, transient in within a few days.
The slightly different profile of post-vaccination reactions after the administration of the vector vaccine compared to the mRNA vaccines results from the differences in the mechanisms of action of these preparations. However, it is neither more intense nor more dangerous. Reports of flu-like conditions in some people vaccinated with the first dose of AstraZeneki coincide with the observations made during clinical trials "
Experts also recalled that in the conducted clinical trials of both mRNA vaccines from Pfizer / BioNTech and Moderny, as well as the AstraZeneki vector vaccine, 100% effectiveness was observed in protecting fully vaccinated people from the necessity of hospitalization in the event of possible coronavirus infection. In addition, all three vaccines offer 100% protection against death from COVID-19.
The statement was signed, among others, by prof. Robert Flisiak from the Polish Society of Epidemiologists and Doctors of Infectious Diseases and an employee of the Medical University in Białystok, prof. dr hab. Jacek Jemielity from the University of Warsaw, prof. dr hab. Andrzej Matyja from the Supreme Medical Council and an employee of the Jagiellonian University, prof. dr hab. Krzysztof Pyrć from the Jagiellonian University, dr hab. Piotr Rzymski from the Medical University of Karol Marcinkowski in Poznań, or prof. dr hab. Joanna Zajkowska from the Polish Society of Epidemiologists and Doctors of Infectious Diseases and an employee of the Medical University in Białystok, prof. dr hab. Krzysztof Simon from the Polish Society of Epidemiologists and Doctors of Infectious Diseases.
AstraZeneca vaccine - effectiveness
The information on the website of the Office for Registration of Medicinal Products, Medical Devices and Biocidal Products shows that the effectiveness of AstraZeneca is 62.6% in people who received two doses of the vaccine at intervals of 3 to 23 weeks.
As reported by The Lancet,the effectiveness of AstraZeneca is greater when the interval between the first and second doses is threemonths and is 81 percent. efficacy (compared to 55% if the second dose was given over a period of 6 weeks or less). The data is the conclusion of a study by Oxford scientists who combined data from randomized trials conducted in the UK, Brazil and South Africa, which included a total of 17,178 people.
The efficacy evaluation was supported by the results of the immune response test in people aged 18-55. In the group that received the second dose of the vaccine with a longer delay, the level of antibodies was more than twice as high.
Protection against COVID-19 appears approximately 3 weeks after the first dose of the COVID-19 Vaccine AstraZeneca vaccine is given. According to the manufacturer, people vaccinated with the second dose may not be fully protected until 15 days after its administration.
It is not yet known how effective the vaccine is in people over the age of 55.