Corona vaccines from BioNTech/Pfizer & Moderna: The most important questions

Corona vaccines from BioNTech/Pfizer & Moderna: The most important questions

In the fight against the coronavirus pandemic, great hopes rest on vaccination against the coronavirus. On December 21, 2020, the mRNA vaccine from BioNTech and Pfizer (BNT162b2, also: Tozinameran or Comirnaty®) was the first vaccine against COVID-19 to be approved in the EU, and thus also in Germany. A few days later, vaccination of the population began across Europe. A second, similar vaccine, Moderna’s mRNA vaccine (mRNA-1273 or Spikevax®), was approved on January 6, 2021.

Rapid vaccination of as large a part of the population as possible is essential to stop the coronavirus pandemic. But at the same time, many people fear possible side effects or wonder whether it would be better to wait for the vaccination. How safe are the vaccines, and why did they develop so quickly? How does immunization work in Germany, and how well are vaccinated people protected?

In this photo series, we answer the most critical questions about coronavirus vaccination with the mRNA vaccines from BioNTech/Pfizer and Moderna.

How well does the vaccination protect against COVID-19?

For the BioNTech and Pfizer vaccine, study data from over 40,000 participants are available for approval, of which around half received the vaccine twice and the other half a placebo. A total of 170 cases of COVID-19 occurred among the study participants, of which only eight were in the vaccinated group, and 162 were in the placebo group. This results in an arithmetical effectiveness of 95 per cent.

That means 95 out of 100 people who would get COVID-19 without a vaccine stay healthy with a vaccine. This makes the vaccine very effective.

Moderna’s vaccine has an efficacy of 94.1 per cent, according to the pivotal study. The data here is based on a study with around 30,000 participants. After the second dose of the vaccine, the participants developed 196 cases of COVID-19, 11 in the vaccine group and 185 in the placebo group. Severe courses were only observed in the placebo group. According to more recent study data, the manufacturer has slightly corrected the information on effectiveness: The vaccine protects 90 per cent against COVID-19 disease and 95 per cent against severe courses. A possible explanation could be the virus mutations, which have increased significantly compared to the previous study.

When does the vaccination protection start, and how long does it last?

In both cases, the study data suggest that some protection against COVID-19 could already be present after the first vaccination dose. However, both substances only develop their full effect a week after the second vaccination. Please note: As with all other coronavirus vaccines, fully vaccinated people can still contract COVID-19. However, they get sick less often and less severely. Vaccination does not offer 100% protection.

How long the vaccination protection lasts has yet to be discovered. A booster shot with a third vaccination is advisable. This booster vaccination is recommended after three months, especially for older and immunocompromised people, but the recommendation generally includes all people over 12. 

Can vaccinated people infect others?

Even vaccinated people can infect others. Experts assume that vaccinated people infected with the coronavirus usually have a lower viral load and are generally hardly or not at all contagious. Study data also indicate that the BioNTech/Pfizer vaccine could effectively prevent coronavirus transmission to other people.

Corona vaccine: what side effects are possible?

Both vaccines against Corona can – like all vaccines – cause slight side effects or side effects. Comparing the frequency of occurrence, BioNTech/Pfizer’s vaccine might be slightly better tolerated than Moderna’s. A possible reason could be that the Moderna vaccine injects a somewhat more significant amount overall.

In the study participants with the BioNTech/Pfizer vaccine, the most common side effects were:

  • Pain or tenderness at the vaccination site (84.1 per cent)
  • Fatigue (62.9 percent)
  • Headache (55.1 percent)
  • Muscle pain (38.3 percent)
  • chills (31.9 percent)

Sometimes, it also happened:

The same was true of Moderna’s vaccine. Here are some of the most common side effects:

  • Pain, redness, or swelling at the vaccination site (91.6 per cent)
  • Fatigue (68.5 percent)
  • Headache (63 percent)
  • Muscle pain (59.6 percent)
  • Joint pain (44.8 percent)
  • chills (43.4 percent)

More rarely, among other things, there were:

All of these side effects were mild to moderate and resolved quickly. Experts do not consider such effects after vaccination unusual; after all, vaccination triggers an immune response in the body.

Are there also serious side effects and long-term consequences?

Serious side effects were only observed in isolated cases in the pivotal studies (e.g. cardiac arrhythmias in one person in the BioNTech/Pfizer study or paralysis of the facial nerve in three instances in the Moderna study). However, whether there is a connection to the vaccination could not be determined since such symptoms can also occur for other reasons.

Based on isolated reports, there is also the suspicion that people who have previously received derma fillers may suffer from facial swelling after being given the BioNTech/Pfizer vaccine.

Authorities closely monitor such cases even after admission. In Germany, side effects can be reported via the app.

Late Effects and Long-Term Effects: What’s the Difference?

Due to the vaccine’s novelty, there is still no knowledge of possible late effects (i.e. side effects that start after a long time). Still, experts classify the probability of such risks as extremely low. In contrast to medicines, vaccines are not administered constantly over a long period and are quickly broken down again by the body. Side effects, therefore, occur with vaccines after a few weeks at the latest – even in the past, late effects have never been observed with a vaccine.

Long-term effects, i.e. side effects occurring shortly after the vaccination and lasting longer, must be distinguished from this. These effects would also be observed in the context of the approval studies.

How are the allergic reactions to be evaluated?

In sporadic cases, the vaccination can lead to significant allergic reactions. In the case of severe, life-threatening allergies, an individual medical assessment should be carried out as to whether the vaccination can be carried out and which vaccine is best suited. Since such allergic reactions occur in the first few minutes after vaccination, medical follow-up is recommended to be able to react immediately if necessary.

Is vaccination dangerous for seriously ill people?

Especially at the beginning of the vaccination campaign, isolated deaths close to the vaccination caused a stir. However, investigating these cases did not reveal any connection to the vaccination. Instead, the deaths could be attributed to the fact that, at the beginning, particularly old and seriously ill people were vaccinated, whose deaths occurred for other reasons. In principle, however, it cannot be ruled out that side effects such as fever or an allergic reaction may have severe consequences for extremely frail people and put too much strain on the body – an individual assessment is therefore advisable.

Myocarditis: Is inflammation of the heart muscle a possible side effect?

In sporadic cases, heart muscle ( myocarditis ) and inflammation of the pericardium have occurred in connection with the vaccines from BioNTech/Pfizer and Moderna. Corresponding cases were usually registered three to four days after the first or second vaccination. Young men and women were particularly affected. Since myocarditis and pericarditis occur more frequently in people under 30 years of age after immunization with the Moderna vaccine, the Standing Vaccination Committee recommends only vaccinations with the BioNTech/Pfizer vaccine for people in this age group and pregnant women. This recommendation also applies to the second and third vaccinations.

No side effects – does the vaccination not work?

Vaccination reactions are considered normal and indicate that the immune system is working. Data from previous vaccinations show that the BioNTech/Pfizer vaccine’s side effects, especially that of Moderna, are usually more severe with the second vaccination than with the first. By the way: With the vector vaccine from AstraZeneca, it is precisely the other way around.

If the vaccination reaction after the first injection with the mRNA vaccines is extreme, it could indicate that you already had a coronavirus infection without noticing it. In this case, the vaccination serves to refresh the existing protection.

Conversely, this does not mean that the vaccination has not worked if there are no side effects. For some people, the reaction to the vaccine is subliminal, with no visible symptoms.

How safe is the coronavirus vaccine for pre-existing conditions?

The study participants for the BioNTech/Pfizer vaccine included people of all ages, including people with chronic pre-existing conditions or overweight. According to the American approval authority FDA examiners, there are also no safety concerns in these risk groups that would speak against the vaccine. On the contrary, fewer side effects were found in the group of over 55-year-olds than in the younger ones.

The study data for Moderna’s vaccine also represent a broad demographic. The participants were between 18 and 95 years old. People with chronic diseases such as diabetes or COPD were also included.

In both cases, however, the original study data did not include all groups of people, or at least not a sufficient number – for example, pregnant women and children were excluded from the pivotal study and people living with HIV were not sufficiently represented. In the meantime, further studies have been carried out on vaccination in children and during pregnancy. Therefore, whether the data situation is sufficient in each case should be considered. Even with known allergies, what vaccinations should be regarded as should be discussed in individual cases.

How does the coronavirus vaccination work?

An injection is administered into the upper arm muscles for the coronavirus vaccination. In the case of the BioNTech/Pfizer vaccine, a second dose is required 3 to 6 weeks after the first vaccination. The Moderna vaccine gives the two injections 4 to 6 weeks apart. To vaccinate more people at least once in a shorter time, it is currently being examined whether these vaccination intervals can be further increased.

Before the vaccination, a patient questionnaire determines whether certain pre-existing conditions, such as allergies, exist. After the injection, there is a short follow-up observation to react quickly in the event of side effects.

Where does the vaccination take place?

The vaccinations were initially carried out in specially set-up vaccination centres to simplify logistics. Still, since April 2021, they have also been possible with general practitioners or company doctors – vaccination centres were gradually closed again. Mobile vaccination teams carry out the vaccinations in care facilities.

A unique feature of the mRNA vaccines is their sensitivity: The vaccine from BioNTech/Pfizer has to be transported and stored at extremely low temperatures. In addition, the vaccine should not be exposed to any vibration. Once thawed, it can be stored in the refrigerator for a maximum of 31 days and transported within the first 12 hours. Before it is vaccinated, the vaccine must be diluted and can then be stored at room temperature for a maximum of six hours. For Moderna’s vaccine, the required temperature is -25 to -15 °C. The vaccine can be stored in the refrigerator for 30 days.

First, is AstraZeneca and then the mRNA vaccine possible?

Due to possible side effects, the Standing Vaccination Committee in Germany recommends that the vaccine from AstraZeneca (Vaxzevria) should only be used in people over 60. But what if you are younger and have already received your first vaccination with this vaccine? Then, the official recommendation is to carry out the second vaccination with an mRNA vaccine – preferably twelve weeks after the first vaccination dose. In July, the Standing Committee on Vaccination expanded this recommendation and now advises that, regardless of age, a first vaccination with the AstraZeneca vaccine should always be followed by a second vaccination with an mRNA vaccine. The interval between the two vaccinations should be at least four weeks.

How well does the vaccination work in such a case?

Since there initially needed more study data on this so-called heterologous vaccination scheme or cross-vaccination, scientists* used data from animal experiments and findings on such vaccination schemes for other diseases to answer this question. These suggested that combining different vaccines could result in an improved immune response.

In the meantime, various studies confirm this – the vaccination’s effect is not impaired but even strengthened. Study data show significantly increased antibodies after cross-vaccination (compared to immunization with the same vaccine). The combination of the vaccines is very effective and could improve the protective effect compared to a pure vaccination with Vaxzevria, especially for the Delta variant.

What side effects are possible?

Even if there is not much study data on the effectiveness, there is at least already knowledge about the possible side effects. Preliminary study results indicate that when the vaccines from AstraZeneca and BioNTech/Pfizer are combined, acute side effects such as headaches, chills or fatigue occur more frequently after the second vaccination dose. As a rule, the vaccination reactions are mild and subside after a few days. The study data relate to an interval of four weeks between the two vaccinations. Studies also indicate that such vaccination reactions are milder if the interval between the two vaccinations is greater.

Johnson & Johnson: Booster with mRNA vaccines?

Even after a single dose of the Johnson & Johnson vaccine, boosting with an mRNA vaccine is recommended. Study data show that this significantly improves vaccination protection. The booster should be given by four weeks after the first vaccination.

Is the SARS-CoV-2 test positive after a corona vaccination?

Some people think they are initially corona-positive immediately after being vaccinated against the coronavirus, so a test for SARS-CoV-2 would indicate an infection. This is not the case because the vaccination cannot infect you with the coronavirus, and the vaccination does not contain any other substances that a coronavirus test would classify as an infection. The vaccines only collect information about the blueprint of a harmless part of the virus, the spike protein.

If the test result is positive immediately after the vaccination, the test result could be incorrect  – this can happen in particular with rapid antigen tests, which is why antigen tests always require confirmation by a PCR test if the result is positive. Another possible explanation is that you got infected shortly before or after the vaccination.

You should also pay close attention to the type of corona test you do. Antigen and PCR tests indicate a current coronavirus infection. Antibody tests, on the other hand, detect antibodies against the coronavirus, i.e. they show whether someone has already been infected with COVID-19 or has been vaccinated against it. Therefore, they are usually positive sometime after vaccination. However, these tests need to show how good the protection against infection with the coronavirus is.

Conversely, a negative antibody test does not necessarily mean no immunity. Because protection against COVID-19 is not only provided by antibodies – the so-called T-cells also play an essential role in defending against this virus.

Who is vaccinated, and when?

For the order of distribution of the vaccine among the population, a prioritization was set in an ordinance by the Federal Ministry of Health, which was primarily based on the recommendations of the Robert Koch Institute (RKI). For example, people over 80, residents and carers of old people’s and nursing homes and other people with a high risk of infection were vaccinated first. In May 2021, it was announced that prioritization would be removed from June 7.

The vaccination is free of charge for the population – regardless of the respective health insurance.

Who can’t get vaccinated?

The BioNTech/Pfizer vaccine will initially only be available for people over five because its effectiveness and safety in younger children have not yet been adequately studied. The vaccine’s initial approval included people aged 16 and over but was later expanded based on new data. The Moderna vaccine was initially available from 18 after being approved (up to eleven years at a reduced dose) from the age of six.

In the meantime, the recommendation of the Standing Vaccination Commission also provides for vaccination for all children and adolescents from the age of five. Between the ages of five and eleven, the STIKO recommends a one-time vaccination with the vaccine from BioNTech/Pfizer in a reduced dose. In this age group, vaccination was initially only recommended for pre-existing conditions and contact with risk groups – three vaccine doses are still recommended for pre-existing conditions and two for contact with risk groups.

Pregnant and breastfeeding women, as well as people with certain pre-existing conditions, should also not be vaccinated at the beginning. However, if there is an increased risk of exposure, the Standing Vaccination Commission recommends that pregnant women be vaccinated after an individual assessment. In September 2021, STIKO changed this recommendation and now advises all pregnant women (from the second trimester of pregnancy) and breastfeeding women to have a double vaccination with the mRNA vaccine from BioNTech/Pfizer.

Regarding known allergies, whether vaccination is an option is discussed on a case-by-case basis.

How many people need to be vaccinated to stop the coronavirus pandemic?

The following applies: the more vaccinated, the better the protection of unvaccinated people since the virus can no longer spread beyond a specific immunity rate. This principle is known as herd immunity.

Initially, it was assumed that in the case of the SARS-CoV-2 coronavirus, around 60 to 70 per cent of the population would have to be immune (either through a survived infection or through vaccination) for this herd immunity to be achieved. More recent calculations assume  80 per cent immunity in the population, sometimes even higher values. Whether herd immunity is even possible in the coronavirus case is now controversial.

On the one hand, it is still being determined how long the immunity lasts after vaccination and after an infection. If you have to refresh your vaccinations regularly, herd immunity becomes at least more difficult. Herd immunity can also only work if vaccinated people cannot infect others – which, according to recent findings, is possible despite vaccination. In addition, a high willingness to vaccinate is required since younger children and some other groups of people cannot be vaccinated at the moment – the higher the proportion of immune adults should be, an estimated 85 per cent. There is also the danger that new virus mutations could undermine immunity.

This shows how important it is for everyone to be vaccinated and thus protected. The quicker this happens, the better. The approval of further vaccines could accelerate the population’s immunization. However, herd immunity in Germany is insufficient to stop the pandemic: people worldwide must be immunized accordingly.

How do the BioNTech/Pfizer and Moderna mRNA vaccines work?

The abbreviation mRNA stands for the English term “messenger RNA” in German: “messenger ribonucleic acid”. mRNA typically serves as a messenger substance in the body, with which the body cells receive the information to produce specific proteins (proteins).

The coronavirus vaccine also uses this function: With the vaccination, the cells are sent the message to replicate a small piece of the so-called spike protein. This is a harmless piece of the outer shell of the coronavirus, which the virus uses typically to dock onto cells.

As the body recreates these bits due to vaccination, the immune system can become familiar with recognizing and fighting the spike protein. In this way, our body can react quickly and successfully in the event of a later infection with the coronavirus.

You can read detailed information on how mRNA vaccines work here.

Why was the coronavirus vaccine developed so quickly?

Usually, developing a vaccine takes several years, but for the vaccine from BioNTech/Pfizer and Moderna, approval was applied for after just a few months. However, the fear that the vaccines are less safe and that important steps have been skipped or shortened is unfounded. The accelerated development had other reasons:

  • Financial resources:  Significant financial resources flowed into the development of the vaccine, also from the federal government. In this way, many more people could work on the development simultaneously, and steps that would otherwise have to be carried out one after the other could be carried out in parallel.
  • Cooperation with approval authorities: The approval process has also been accelerated without lowering the relevant standards. Instead, the topic was treated with the highest priority, more employees were assigned to review the studies, and the experts from the authorities were given an insight into the study data before the start of the approval process so that they could view and evaluate it earlier.
  • Existing knowledge: Even though SARS-CoV-2 is a novel virus, the research is built on knowledge of similar viruses such as SARS and MERS. Study data on replicating spike proteins and RNA vaccines already existed and could be used. Scientists worldwide exchanged data and findings in record time that could be built on.

On December 21, 2020, the European Medicines Agency EMA and then the EU Commission decided on the vaccine’s approval from BioNTech/Pfizer in Europe – and thus also in Germany. For example, no emergency approval was granted, as in Great Britain, but “conditional market approval”. In contrast to emergency approval, the data is checked even more thoroughly, and the manufacturers are not released from their liability. So, the procedure takes a little longer, but it is safer. The first BioNTech/Pfizer vaccine vaccinations were carried out in Germany on December 26, 2020.

The Moderna vaccine received conditional marketing approval on January 6, 2021.

At the beginning of October 2022, the conditional market approval for both vaccines was converted into a standard authorization by the European Commission on the recommendation of the EMA. This means that the approval no longer has to be renewed every year.


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