Current status on the application: Is a third vaccination necessary?
A crossed vaccination schedule consisting of an initial vaccination with Vaxzevria and a second mRNA vaccination protects against a severe covid 19 course.
Physicians nevertheless are observing increased breakthrough infections in twice-vaccinated individuals due to the omicron variant. The Standing Commission on Vaccination (STIKO) therefore recently changed its recommendations: it now recommends an additional third vaccination in order to maintain the best possible vaccination protection against the Omikron variant.
According to the STIKO, an additional dose of an mRNA vaccine (BioNTech/Pfizer, Moderna) is suitable as a booster. For those under 30, the BioNTech vaccine should ideally be used.
What kind of vaccine is it?
The Vaxzevria vaccine (AZD1222) from the manufacturer AstraZeneca is the first approved vector vaccine against Covid-19 disease in the European Union. It specifically trains the human immune system against the pathogen Sars-CoV-2. In clinical trials, Vaxzevria (AZD1222) conferred good protection against Covid-19.
With the vaccination, the blueprint enters the human cell. The cell then begins to produce the viral protein: It then presents it on its surface. The human immune system then specifically forms antibodies and immune cells (T cells, B cells) against the spike protein. This learned immune response can protect those vaccinated from Covid-19 outbreaks in the event of infection.
Vaxzevria (AZD1222) has a conditional marketing authorization from the European Medicines Agency (EMA) for the European market. This means that the approval of Vaxzevria (AZD1222) is subject to conditions relating to safety and efficacy. These conditions are continuously and closely monitored and reviewed by experts at the Paul Ehrlich Institute (PEI) and the EMA.
For more on the mode of action of vector vaccines, see our article Vector vaccines.
Efficacy against Covid-19
According to the RKI, the AstraZeneca vaccine has an efficacy of 80 percent. Protection against severe courses is close to 100 percent, especially in seniors.
Full vaccine protection with Vaxzevria (AZD1222) is achieved two weeks after the second dose of vaccine.
According to the University of Oxford, the vaccine Vaxzevria (AZD1222) also provides protection against severe courses in the event of infection with the British variant B.1.1.7. This was found in a study of 499 participants.
The authors found that those who had been vaccinated in advance with the AZD1222 vaccine had significantly lower levels of virus in the event of infection than the control group.
For more information on the currently circulating coronavirus variants, click here.
Not approved for children and adolescents
Data on efficacy in children and adolescents up to 18 years of age are not available. Consequently, Vaxzevria vaccine (AZD1222) is not licensed for this age group in the European Union.
Tolerability and side effects
AstraZeneca’s vaccine is generally well tolerated. However, any side effects that occur continue to be closely monitored by the Paul Ehrlich Institute (PEI) and updated on an ongoing basis. Serious side effects associated with the AstraZeneca vaccine continue to be very rare.
The Standing Committee on Vaccination (STIKO) adjusted its vaccination recommendation on May 12, 2021, for younger persons under 60 years of age: Persons who have already received a first vaccination with the AstraZeneca vaccine should receive an mRNA vaccine (Comirnaty, Moderna) instead of a second Vaxzevria dose (heterologous vaccination schedule).
For more information on the combined vaccine administration of the AstraZeneca vaccine and the BioNTech vaccine, click here.
Common side effects
However, about one in ten vaccinated people develop moderate side effects in response to vaccination. They are similar to those that usually occur after vaccinations. The side effects usually disappear within a few hours or days. They include:
- Mild to moderate pain or swelling at the injection site.
- @ headache
- Fatigue
- Joint pain
- mild feeling of illness
- chills
- slight fever
Severe side effects
Serious side effects, for example severe (anaphylactic) reactions are very rare after vaccination.
Cerebral vein thrombosis
Appropriate warnings will be promptly included in the technical and directions for use.
In examining blood samples from affected patients, researchers at Greifswald University Medical Center apparently identified a possible cause for the observed adverse events. According to this, in rare cases platelets are activated by the vaccination – similar to the processes involved in wound healing. This could be a possible explanation for the observed events. However, robust data on this are still pending.
PEI emphasizes that anyone who experiences increasing discomfort, develops pinpoint hemorrhages, or severe persistent headache following a received vaccination of Vaxzevria (AZD1222) should seek immediate medical attention.
Capillary Leak Syndrome
In addition, the manufacturer, AstraZeneca, recently reported very rare cases of capillary leak syndrome (CLS) that occurred in conjunction with Vaxzevria vaccination. One case with fatal outcome was named.
CLS is considered a rare disease. It is characterized by a misdirected inflammatory reaction and a dysfunction of the blood and lymph vessels. In the specific case, this means that for the duration of the CLS episode, the mechanisms of vasodilatation are disturbed and the blood vessels become permeable.
As a direct consequence, the blood pressure of affected individuals drops rapidly and there is an influx of fluid into the tissues. This results in rapid weight gain with progressive swelling of the arms and legs. This in turn leads to a steady thickening of the blood (hemoconcentration), possibly resulting in organ failure or shock.
PEI notes that in rare cases, systemic CLS can also be caused by Covid-19 infections.
Transverse Myelitis
In isolated cases, physicians report another very rare complication observed in temporal association with Vaxzevria administration (traverse myelitis, TM).
The symptoms vary depending on the affected part of the spinal cord. They range from sensory disturbances, fatigue, malfunction of the gastrointestinal tract, movement abnormalities to paralysis.
Although the documented reports are sporadic isolated cases, the European health authority nevertheless sees at least a possible link between Vaxzevria vaccination and TM. However, the incidence of this complication is unknown.
In this context, the EMA emphasizes that despite these individual case reports, the risk-benefit ratio for Vaxzevria remains clearly positive.
Tolerated even in allergic patients
According to current knowledge, the vaccine is also suitable for allergy sufferers. However, allergy sufferers should inform their vaccinating physician of any known allergies prior to vaccination. In the event of an allergic reaction, the doctor can then quickly take countermeasures.
In addition, you should remain in the practice or vaccination center for at least 15 minutes after the vaccination for medical monitoring.
Vaccination during pregnancy
However, this assessment is based on preliminary studies in animal models. Reliable data on effects and side effects in pregnancy are not yet available for Vaxzevria (AZD1222).
The decision as to whether vaccination is advisable in pregnancy should be clarified in close consultation with your treating physician. He can best assess the benefit and risk for you.
Vaccination in case of illness
According to the EMA, you can be vaccinated in case of mild cold symptoms. However, in case of a more severe illness, you should postpone an upcoming vaccination.
Vaccination and anticoagulants
Persons taking anticoagulants as a preventive measure should make the doctor aware of this in advance. The general precautions then apply: The vaccine must be administered particularly cautiously in the case of anticoagulation therapy.
Vaccination with immunodeficiency
Storage and shelf life
In contrast to the already tested vaccines Comirnaty from the manufacturer BioNTech/Pfizer and Vakzin from Moderna, Vaxzevria (AZD1222) can be stored in the refrigerator for a longer period of time.
The maximum storage time specified by the manufacturer in the unopened state is about six months. Vaxzevria (AZD1222) is supplied in tin containers of 8 or 10 vaccine doses each.
