Coronavirus vaccine BioNTech / Pfizer (Comirnaty)
Updated onMaximilian Reindl studied chemistry and biochemistry at the LMU in Munich and has been a member of the editorial team since December 2020. He will familiarize himself with medical, scientific and health policy topics for you in order to make them understandable and comprehensible.
More posts by Maximilian Reindl All content is checked by medical journalists.The vaccine Comirnaty from the two manufacturers BioNTech and Pfizer was the first vaccine against the Sars-CoV-2 virus to receive conditional marketing authorization from the European Medicines Agency. The vaccine uses a novel mRNA technology. In clinical approval studies and the ongoing vaccination campaign, it has proven to be very effective and mostly well tolerated. Read here what is known about effectiveness, side effects and the mechanism of action.
What kind of vaccine is it?
The BNT162b2 vaccine from the manufacturers BioNTech and Pfizer (trade name: Comirnaty) is a reliable vaccine that protects against the Sars-CoV-2 coronavirus. The vaccination campaign with this vaccine began in Germany on December 27, 2020.
Comirnaty is a so-called mRNA vaccine. With this type of vaccine, the human cell is supplied with the blueprint for a viral protein: the so-called Sars-CoV-2 spike protein.
This characteristic spike protein sits on the outer shell of the coronavirus. Through the vaccination, the human cells produce the viral protein molecule. The immune system remembers the structure of the exogenous protein and reacts to this stimulus - it learns to defend itself against Sars-CoV-2.
Comirnaty itself does not contain any viral components. The vaccine cannot therefore cause the disease Covid-19. The vaccine is suitable for immunizing people aged 12 and over.
It has shown a high level of effectiveness in clinical studies. Adverse reactions were rarely observed in the registration studies. Based on this positive benefit-risk ratio for public health, it received conditional approval for the European market in an accelerated procedure on December 21, 2020.
You can find more information on the approval process for medicinal products in the European Union and the course of clinical investigations here.
Effectiveness against Covid-19
A large-scale clinical study as part of the approval process in the EU showed that Comirnaty effectively prevents typical Covid-19 symptoms in people aged 16 to 65 - and above. In this way, severe courses of Covid-19 can be prevented.
The study comprised 44,000 study participants. People aged 16 and over who, among other things, also belonged to risk groups were examined.
Experts named those people who have an increased risk of severe courses for Covid-19 as risk groups. This affects people who have pre-existing conditions such as asthma, chronic lung diseases, diabetes, high blood pressure or overweight.
How long is the vaccination protection?
A preventive effect occurs after the first vaccination dose - according to the study data, the effectiveness after the second vaccination dose is 95 percent.
Whether the vaccine also prevents infected people from passing the virus on to others (sterile immunity) and thus stopping the spread of the corona virus has not yet been conclusively proven. How long the vaccination protection lasts is currently still being monitored.
Studies, however, suggest a so-called B-cell-mediated immunity: This means that the immune system develops an immunological memory. In specialist circles, this is an indication of longer-term protection against Sars-CoV-2.
Effectiveness against mutations
According to a laboratory study, there is increasing evidence that Cormirnaty could offer protection against certain coronavirus mutations - in particular against the much-discussed British variant B.1.1.7 as well as the South African B.1.351 line.
Researchers investigated how the individual structural changes (mutations) of the spike protein affect the vaccination protection of Comirnaty.
To do this, the researchers isolated sera from 20 test persons who had previously been vaccinated with two doses of Comirnaty. They then checked the ability of the antibodies contained in them to see whether they could neutralize (artificially generated) virus variants - so-called pseudoviruses. Although this is a pure laboratory test, the results are considered by experts as an indication of continued vaccination protection.
Tolerability and side effects
Comirnaty is usually very well tolerated. The majority of the reported adverse reactions are temporary local reactions at the injection site or typical general vaccination reactions - these are usually mild to moderate.
All side effects that occur are closely monitored and documented by the Paul Ehrlich Institute (PEI) and the findings are regularly published in order to ensure transparency and safety of the vaccination campaign.
According to the safety report of the Paul Ehrlich Institute (PEI), around 55 million people in Germany have already received a dose of the BioNTech / Pfizer vaccine (as of June 30, 2021). This number is distributed among around 24 million people who have already been fully vaccinated and around 31 million people who have been vaccinated for the first time.
Currently reported suspected side effects
For the period from December 27, 2020 to June 30, 2021, a total of 49,735 suspected side effects or vaccination complications were reported to the PEI. This results in a reporting rate of 0.9 cases per 1,000 vaccine doses administered. The published figures from the PEI suggest that women are more likely to experience side effects.
In the vast majority of cases, however, the reported complications had already subsided by the time they were reported.
Adverse Events of Special Interest
On the basis of individual case reports of observed myocarditis in connection with the administration of a second dose of vaccine with Comirnaty, the Pharmacovigilance Risk Assessment Committee (PRAC) of the European Medicines Agency decided to include corresponding warnings in the patient information.
These are very rare reports. Whether there is actually a causal connection between vaccination of Comirnaty and myocarditis has not yet been conclusively clarified - a connection is possible, however.
The PEI emphasizes that there are no systematic studies, so that the frequency of such occurrences cannot be reliably determined - only estimates are therefore available. The Israeli Ministry of Health reports 121 cases from around 5 million inoculated doses. This would correspond to around 2.4 cases per 100,000 vaccination doses - US reports, however, estimate the frequency at one case per 100,000 vaccinations.
The vast majority of the few documented cases have been described as mild. In line with this, the PRAC emphasizes that the risk-benefit assessment for Comirnaty continues to be positive.
Serious events
However, around 12 percent of these reports - i.e. 5,781 cases - were serious. This means that the reporting rate for serious incidents is 0.1 cases per 1,000 vaccine doses administered.
Serious reactions include those cases that had to be treated in hospital after receiving a vaccine or were classified as "medically important".
Of particular interest - based on 10 million vaccine doses administered (as of April 2, 2021) - the following isolated events:
- Anaphylactic reactions: An excessive immune reaction to the vaccine has been observed extremely rarely. A total of 87 anaphylactic reactions were observed - 66 cases with the first vaccine and 21 cases with the second vaccination.
- Deaths: There were 321 deaths temporally related to vaccination with Comirnaty. The average age of those affected was 85 years. The vast majority suffered from advanced pre-existing conditions such as carcinoma, kidney failure, heart disease and arteriosclerosis.
- Thrombocytopenia: 17 cases of thrombocytopenia following vaccination with Comirnaty were reported to the PEI. It is associated with a decrease in the number of blood platelets and punctiform hemorrhages. According to the PEI, the few reported cases are very likely not related to vaccine administration.
- Sinus vein thrombosis: 7 cases of serious sinus vein thrombosis were reported to the PEI. According to the PEI's assessment, there is currently no connection with Comirnaty.
Moderate vaccination reactions possible
The most common side effects include mild to moderate pain and swelling at the injection site, as well as tiredness, headache, muscle and joint pain, and fatigue. Mild fever or chills were also observed. However, these usually subside within hours to a few days. In rare cases, the Paul Ehrlich Institute was also reported delayed local reactions with reddening, induration and a feeling of tension from the eighth day onwards.
So far there is no evidence that vaccination with Comirnaty is dangerous after a Sars-CoV-2 infection that has already passed unnoticed.
Also compatible with allergies
According to the current state of knowledge, there is no contraindication for people with allergies. This means that allergy sufferers can get vaccinated. If you have any known allergies, you should still tell your vaccinating doctor so that adequate medical care and monitoring can be provided if necessary.
According to the recommendations of the PEI, vaccinated persons should be observed for vaccination reactions for at least 15 minutes. People who developed anaphylaxis (hypersensitivity reaction) after the first dose should not receive a second dose.
Vaccination during pregnancy?
The Standing Vaccination Commission has recommended the use of Comirnaty for pregnant women from the second trimester onwards since September 17, 2021. The series of vaccinations usually consists of two doses of vaccine, which should be administered three to six weeks apart.
If pregnancy falls between the first and second vaccination, the second vaccination dose should be delayed from the second trimester.
Breastfeeding mothers should also be encouraged to take advantage of a vaccination offer in order to minimize the risk of a child's infection. The antibodies in breast milk formed by immunization can represent protective immunity (passive immunization) to protect the infant.
Vaccination of children and adolescents
The Comirnaty vaccine was also approved for children and adolescents (conditionally) on May 28, 2021. The EMA experts refer to the promising results of a phase III study on around 2,000 children and adolescents aged 12 to 15 years.
The Standing Vaccination Commission (STIKO) has been recommending the Comirnaty mRNA vaccine from BioNTech / Pfizer for the group of 12 to 17 year olds since August 16, 2021. After careful review of new findings, the benefits of vaccination outweigh the very rare side effects of vaccination in this age group. This assessment by the STIKO takes into account, in particular, the increasing spread of the delta variant and the associated higher health risks in a possible fourth wave of infections.
Postpone vaccination in case of illness
If you develop a serious, febrile illness prior to a scheduled vaccination appointment, you should postpone your vaccination appointment. In this case, contact your vaccination center or the doctor treating you as early as possible. If you have only minor infections, you can get vaccinated - but clarify this with your doctor.
Beware of anticoagulants
If you are taking anticoagulants (anticoagulation therapy), tell your doctor. In this case, the vaccine must be given with particular care, otherwise bleeding or bruising may occur.
Effectiveness in case of immunodeficiency?
The efficacy and safety of Comirnaty in people who are immunodeficient or who are receiving immunosuppressants cannot yet be conclusively assessed.
Dangers of overdose?
In the course of the Comirnaty clinical trial, 52 cases of overdose of the vaccine due to a dilution error occurred. Study participants received 58 micrograms instead of the optimal effective dose of 30 micrograms. No undesirable reactions were reported. In the event of an overdose, however, close monitoring should be maintained after vaccination.
Effects on ability to drive?
Comirnaty has no or negligible influence on the ability to drive and use machines.
Can I take painkillers after a vaccination?
According to a recommendation by the RKI, after vaccination with Comirnaty you can take pain-relieving and fever-lowering medication (ASA, paracetamol, ibuprofen) - but you should discuss this with your doctor beforehand.
The typical vaccine reactions such as mildly febrile reactions or the like are signs that the vaccine is training your immune system. If you suppress this reaction with NSAIDs, this could possibly affect the success of the vaccination. Further data and experience on this are pending.
Possible interactions with other drugs or the simultaneous administration of other vaccines has not yet been systematically investigated. If you are taking certain medications on a long-term basis, it is best to speak to your vaccinating or treating doctor.
Possible further reactions
Fear-related reactions as a result of the needle injection have been reported in isolated cases. If you are afraid of needles, it is best to clarify this with your doctor beforehand. This allows you to take precautions to avoid injury from fainting.
Further information on the subject of "Corona vaccinations: side effects" is available here.
use
Comirnaty is used in a series of vaccinations. This means that two doses of 0.3 milliliters each - 30 micrograms per dose - are administered at least 21 days apart. A second vaccine should be given within 42 days. The vaccine is preferably injected (intramuscularly) into the muscle of the upper arm.
Data on a possible interchangeability of Comirnaty with other Covid-19 vaccines to complete the vaccination series are not available.According to a recommendation from the European Medicines Agency (EMA), people who received a first dose of Comirnaty should also receive a second dose of Comirnaty to complete the series of vaccinations.
logistics
The vaccine is based on a small section of the virus' genetic material, the so-called mRNA. The mRNA is a very sensitive molecule that can break down very quickly.
The vaccine can therefore only be kept for around six months at minus 80 degrees Celsius. Once removed from the freezer, the unopened vaccine can be stored for up to five days at 2 ° C to 8 ° C and around six hours at room temperature before use.
Comirnaty is supplied in a multi-dose vial, the contents of which must be diluted by your doctor before use. One vial (0.45 ml) contains 6 doses of 0.3 ml each after dilution.
Mechanism of action
Vaccines prepare the human immune system to act quickly and specifically against pathogens - it is enabled to defend itself.
The entire genetic information of the corona virus is stored in the virus particle in the form of RNA (ribonucleic acid). A small, well-defined section of this viral genetic information carries the information for the spike protein. It is precisely this RNA segment that is isolated, duplicated and processed into a vaccine as so-called lipid nano-particles during vaccine production.
For this purpose, the RNA is enclosed in small fat particles in order to increase the stability of the viral genetic information. This technology also makes it easier to smuggle this blueprint into the human cell.
As soon as the blueprint arrives in the cell, the human cell begins to produce the spike protein. The cell retains all of its natural functions - however, it now presents the (exogenous) spike protein on its cell surface.
Such processes also happen in the case of a "natural" infection with a virus - the body has developed good defense mechanisms for such cases in the course of evolution: the specific immune defense. And that is exactly what makes the vaccine so effective.
The immune system recognizes the foreign spike protein through a complex interaction of various highly specialized cells and initiates countermeasures. At the end of a signal cascade, so-called B cells are ultimately formed. They have two central tasks: to form antibodies and, as memory B cells, to “remember” the foreign (viral) antigen.
When this process of immunization is complete, experts speak of an adapted (“learned”) immunity. In the event of a real virus infection, the immune system can therefore act quickly and specifically against the Sars-CoV-2.
The faster our immune system can recognize and fight the virus in the event of a Sars-CoV-2 infection, the less severe it will be and the lower the possible consequential damage for those affected.
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