COVD-19 vaccination – answers to the most important questions

Vaccination provides protection against developing a severe form of COVID-19 and against any potential long-term consequences. Vaccination also helps to ease the burden on the healthcare system and prevent shortages of medical care. This article explains how the vaccines work and how safe and effective they are.

At a glance

  • Vaccination against COVID-19 has an important role to play in helping to stem the pandemic.
  • The COVID-19 vaccines approved in Germany are all very effective and safe. Serious side effects are very rare.
  • In particular, vaccination provides protection against getting the severe form of COVID-19, even if infected with a variant of the virus – provided people are fully vaccinated.
  • Immunity declines over time. A vaccinated person can still become infected. However, people who have been vaccinated are far less likely to require treatment in intensive care units.
  • STIKO (Ständige Impfkommission), the Standing Committee on Vaccination in Germany recommends vaccination against COVID-19 for all people aged 12 years and over, as well as for children aged 5 years and over who have a pre-existing health condition or are in contact with high-risk groups. Children without a pre-existing condition can also be vaccinated on request.
  • To prevent breakthrough infections, STIKO also recommends a booster vaccine dose following double vaccination for everyone aged 12 and older and for children aged 5 and older who have a pre-existing health condition.
  • STIKO recommends a second booster vaccine for people who are at a particularly high risk of infection or of developing a severe form of the illness. 

Note: The information in this article cannot and should not replace a medical consultation and must not be used for self-diagnosis or treatment.

COVID-19 vaccination: doctor vaccinating older woman with an injection into her upper arm. They are both wearing full face masks.

What are the benefits of COVID-19 vaccinations?

Vaccinations play a crucial role in containing the pandemic. The more people that are vaccinated against COVID-19, the more quickly the spread of SARS-CoV-2 and its variants can be halted.

In particular, there is less risk of becoming seriously ill with COVID-19 or developing long-term health problems and symptoms after a coronavirus infection – also known as long COVID.

Being vaccinated also protects other people who cannot be vaccinated because of certain pre-existing conditions or because vaccination is not recommended for them. The higher the vaccination rate, the better society as a whole is protected.

Important: It should be noted that even people who have been vaccinated can still be infected with SARS-CoV-2 and pass on the virus. It is therefore important to continue observing the latest infection control measures. It is also critical for people to top up their immunity when needed with a booster vaccine.

How do vaccinations work?

The video below explains how a vaccination works.

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What COVID-19 vaccines are there and how do they work?

Several coronavirus vaccines have been approved in Germany and the European Union. These are divided into mRNA vaccines, viral vector vaccines and protein-based vaccines.

The vaccines are all free from pathogens that are capable of replicating and cannot trigger illness. They are therefore classed as inactivated vaccines.

mRNA vaccines

Some vaccines such as those manufactured by BioNTech/Pfizer (Comirnaty) and Moderna (Spikevax) are mRNA vaccines. These are new kinds of vaccines that are classed as gene-based vaccines. Like other gene-based vaccines, they offer the advantage that they can be manufactured in the laboratory very quickly and cost-effectively.

The principle behind all COVID-19 mRNA vaccines is very similar. They are made from messenger ribonucleic acid (mRNA), a natural component of all cells. The mRNA in a body’s cell contains the blueprint for the building blocks of every cell in the body. In the case of the vaccines, the mRNA bears the blueprint for the spike protein, which sits on the surface of SARS-CoV-2.

The blueprint for the spike protein is packaged in nanoparticles. These are tiny lipid particles that are able to enter cells. As studies have shown, they do not pose any risk to the human body.

After vaccination, the body’s cells use the blueprint to manufacture the spike protein themselves. This unfamiliar protein is not recognized by the body and triggers an immune response. The immune system is activated and produces antibodies that attack the spike protein and store information about how to fight it. If a person who has been vaccinated ever comes into contact with the spike protein from the actual virus later on, the immune system is able to mount a rapid, targeted response.

Important: The mRNA from the vaccines does not remain stable in the human body for long and is broken down quickly. Once this happens, the spike protein can no longer be produced. 

Viral vector vaccines

The other type of coronavirus vaccine is viral vector vaccines, such as Vaxzevria, manufactured by AstraZeneca, and the Janssen COVID-19 vaccine manufactured by Janssen Cilag International/Johnson & Johnson.

A viral vector vaccine delivers the blueprint to the vaccinated person by means of a vector, i.e. a carrier, which is usually a virus. 

Like mRNA vaccines, the viral vector vaccine is designed to make the body of the vaccinated person produce a specific viral protein. This is also known as the “spike” protein. Viruses that do not cause illness are used as carrier viruses. They have also been modified to prevent them replicating in the human body. Once the blueprint for the spike protein has entered several cells in the vaccinated person’s body via the vector, the spike protein is produced in these cells and triggers an immune response. Once the blueprint has been broken down, no further spike protein can be produced.

Protein vaccines

The group of protein-based vaccines includes the Nuvaxovid vaccine from Novavax. Unlike mRNA vaccines, which provide the genetic blueprint for the SARS-CoV-2 spike protein, Nuvaxovid contains a laboratory-produced spike protein linked to nanoparticles. That means that the human body does not have to actually produce it to trigger an immune response. To heighten the immune response – which is less intense than with mRNA vaccines for example – an active ingredient (adjuvant) is added.

Interesting fact: The antigen, i.e. the protein that stimulates the immune response, chosen by most of the vaccine manufacturers was the SARS-CoV-2 spike protein. The virus needs the spike protein to enter the human cell. It sits on the surface of the virus, so the immune system can recognize it quickly.

For more detailed information on the COVID-19 vaccines that are approved in the European Union, visit the website of the Paul Ehrlich Institute (PEI).

How safe are COVID-19 vaccines?

All vaccines currently available in the European Union were thoroughly and carefully tested by experts to verify their quality, safety and effectiveness prior to their conditional approval. Furthermore, the use of the vaccines since their approval has been closely monitored to identify any side effects that may occur and any previously unknown risks. 

The approval process is coordinated by the European Medicines Agency (EMA). Approvals are issued by the European Commission.

Important: All approved coronavirus vaccines are generally considered to be safe and severe adverse effects have been very rare to date. 

The Paul Ehrlich Institute (PEI) regularly publishes up-to-date reports on the safety of COVID-19 vaccines. 

What does conditional approval mean?

If medicines or vaccines are urgently required – as in the case of the coronavirus pandemic – it is possible to speed up the testing procedure at the EMA to approve products more quickly. Conditional approvals are valid for one year and can be renewed on an annual basis. They come with certain obligations. For example, the manufacturers must launch or complete studies to clarify outstanding questions. If the obligations have been met and all relevant data has been provided, a conditional approval can be converted into full approval.

For more detailed information on the approval procedure for COVID-19 vaccines, please visit the website of the Paul Ehrlich Institute (PEI).

How effective are COVID-19 vaccines?

It normally takes 10 to 14 days for vaccination to take effect. So people who are vaccinated are not protected straight away.

Protection against getting COVID-19

All of the vaccines approved in Germany so far are highly effective and provide good protection against severe COVID-19 disease.

All of the vaccines approved so far are highly effective and provide good protection against severe COVID-19 disease.

All COVID-19 vaccines require two vaccine doses for primary immunization.

It is still not clear exactly how long this initial protection lasts. The latest research has shown that a booster vaccination is needed for optimum protection, especially against virus variants such as Omicron.

The Standing Committee on Vaccination in Germany (Ständige Impfkommission, STIKO) recommends a booster dose following double vaccination for everyone over the age of 12 and for children aged 5 to 11 who have a pre-existing condition. For information about the precise recommendations, please see the section dealing with the booster vaccine.

Infection and transmission even if a vaccine has been administered

Although the vaccinations provide protection against getting the severe form of COVID-19, people can still occasionally be infected with no symptoms or mild symptoms. 

The data gathered so far suggests that people who are infected with coronavirus despite being vaccinated are likely to shed less virus and that the virus shedding period is also shortened. So experts believe that vaccinated people are less infectious than unvaccinated people, so there is less risk of virus transmission.

Important: To prevent potential infections, STIKO recommends still following the hands, face, space, ventilation (“AHA+L”) guidance, i.e. wearing a mask during everyday life, observing hygiene guidelines, physical distancing and regular ventilation.

Protection against variants of the virus

It is part of the nature of a virus to mutate, i.e. to change over time. However, vaccinations are not automatically ineffective against these variants of the virus. The main factors that determine whether and to which extent the vaccines are ineffective are the extent of the mutation and the points at which it occurs on the spike protein – i.e. whether the human body can still recognize the “real” spike protein based on the information it has on the spike protein from the vaccination.

For example, data already exists in relation to the Delta variant to suggest that the efficacy of the vaccines is only slightly impaired in people who have received primary immunization. If the series of vaccinations has not been completed, however, the effectiveness is significantly reduced. So, to achieve effective protection, it is important to attend every vaccination appointment.

To date, experts are unable to definitively say how effective the available COVID-19 vaccines are at protecting against the Omicron variant, which is the dominant variant in Germany. However, study results suggest that the protective effect of primary immunization against Omicron is significantly lower than against Delta. Despite this, a booster vaccination can significantly improve protection against serious illness due to infection with Omicron.

In addition, vaccine manufacturers are already working on mRNA vaccines that are adapted to the Omicron variant. Experts expect the first “Omicron vaccines” to be approved in early summer 2022.

What reactions to vaccination and side effects might occur?

Drug and vaccine safety is defined by the number and type of symptoms that occur following vaccination. These are classed as reactions to vaccination or side effects. 

Reactions to vaccination

Vaccinations against SARS-CoV-2 coronavirus are often followed by mild symptoms that appear quickly and only last a few days. These are referred to as reactions to vaccination. They include pain, reddening or swelling at the injection site and flu-like symptoms such as shivering, high temperature, headaches and aching muscles. General indisposition and nausea are also possible.

A reaction to a vaccination is not usually a cause for concern but an indication that the immune system has been stimulated as expected. In most cases a reaction to vaccination disappears after just a few days.

A reaction to a vaccination is not usually a cause for concern but an indication that the immune system has been stimulated as expected.

Safe reactions to vaccination are fairly common after administration of all the COVID-19 vaccines used so far. However, some people do not experience any reaction. This does not mean, though, that the vaccination is less effective.

Side effects

There have been rare cases of blood clots (“thrombosis”) following administration of the viral vector vaccines made by AstraZeneca and Janssen Cilag International/Johnson & Johnson. These were accompanied by a drop in the platelet count, referred to by specialists as thrombocytopenia. Some of the blood clots occurred at unusual sites such as in the brain’s venous sinuses (cerebral venous sinus thrombosis or CVST).

The combination of blood clots and thrombocytopenia is a severe adverse effect which may be life-threatening. Potential signs are:

  • shortness of breath
  • abdominal pain
  • swelling in arms or legs
  • severe, persistent headaches
  • petechiae (pinpoint, round spots that appear on the skin as a result of bleeding)

Particular caution is advised if these symptoms occur after the reaction to vaccination has cleared up, i.e. 4 to 16 days after vaccination. If this is the case, medical assistance should be sought immediately.

After the BioNTech and Moderna mRNA vaccines were administered, there were very rarely cases of heart muscle and pericardial inflammation. These generally occurred within 2 weeks of the vaccine being administered, usually after the second vaccination and mostly in younger men.

To date, there are no known serious side-effects to the protein vaccine from Novavax. As this vaccine was only recently approved, the only data available is that from the approval study. Due to the relatively small size of the study, sufficient data has not yet been collected to identify any rare or very rare side effects.

Moreover, any vaccine, like other drugs, can cause allergic reactions in some people. Depending on the severity of the reaction this may be classed as a mild or severe adverse effect. 

Allergic reactions generally occur very rapidly. An observation period of at least 15 minutes is required following all vaccines to allow targeted treatment to be provided where necessary. If severe allergic reactions occur after the first dose of the vaccine, consideration should be given to providing an alternative vaccine for the second dose.

Important: People who are known to be allergic to particular substances should take advice from an allergy center before getting a COVID-19 vaccination.

What causes breakthrough infections of COVID-19?

The term breakthrough infection is applied when a person becomes ill with COVID-19 (i.e. has symptoms) despite being fully vaccinated. It does not apply when a vaccinated person tests positive for a SARS-CoV-2 infection but does not display any symptoms.

Breakthrough infections are not uncommon. While vaccines against coronavirus provide effective protection against developing the severe form of the disease by inhibiting replication of the SARS-CoV-2 virus, they do not stop people from contracting the virus. Many people were also vaccinated so long ago that their immunity has decreased. 

Breakthrough infections are more common when the vaccination rate is high and more of the virus is circulating in the population. In this situation, the probability of vaccinated people contracting COVID-19 increases. This risk can be reduced by a booster vaccine.

Important: Overall, people who have been vaccinated against COVID-19 are far less likely to be infected with coronavirus than people who have not received a vaccine. They are also far less likely to become seriously ill with the virus and to require treatment in an intensive care unit.

The Robert Koch Institute (RKI) publishes weekly reports on the COVID-19 situation in Germany. These offer the latest facts and data about infections and the situation in local hospitals.

Who can get vaccinated against COVID-19?

In Germany, anyone aged 5 or above can now be vaccinated against COVID-19. The following vaccines are available, depending on the person’s age: the two mRNA vaccines Comirnaty (BioNTech/Pfizer) and Spikevax (Moderna), the protein vaccine Nuvaxovid (Novavax) and the vector vaccine COVID-19 Vaccine Janssen. 

For people aged between 12 and 30 and for pregnant women of all ages, the Standing Committee on Vaccination (STIKO) recommends vaccination with the BioNTech/Pfizer vaccine. For adults aged over 30, STIKO recommends the Moderna vaccine. Alternatively, STIKO recommends the Novavax vaccine for people aged over 18. Meanwhile, it is recommended that people aged 60 and above should receive the Janssen vaccine for their initial vaccine dose. In this case, however, STIKO recommends an mRNA vaccine for the second vaccine dose. 

Important: A greater number of breakthrough infections (infections after vaccination) are observed among people who have received the Janssen COVID-19 vaccine for their primary immunization than among those who have received other vaccines. STIKO therefore recommends optimizing immunity with an mRNA vaccine dose – for full primary immunization. This is possible 4 weeks after vaccination with the Janssen vaccine. To be regarded as boosted, a further mRNA dose is required. 

Recommendations for children under 12

For the 5 to 11 age group, STIKO recommends vaccination for children with various pre-existing conditions and children who come into close contact with people at an increased risk of contracting the disease and people who have reduced immunity. These include people taking medication that weakens the immune system, for example.

At present, STIKO does not generally recommend vaccinating children in this age group who have no pre-existing conditions. However, vaccination is possible after consultation with a doctor and if the individual child and parents (or child and guardian) request it.

Vaccine recommendations for pregnant and breastfeeding women

STIKO recommends that previously unvaccinated women who are pregnant or breastfeeding should be vaccinated with the mRNA from BioNTech/Pfizer as of their second trimester of pregnancy. This means that expectant mothers can protect themselves not only from developing a severe case of COVID-19 but also against any potential complications of pregnancy that could be triggered by a coronavirus infection. 

Important: Women trying for a baby but who are not yet pregnant need not have any concerns about being vaccinated against COVID-19. The vaccination does not affect fertility and also offers the best possible protection when trying to conceive.

Where can I get a vaccine?

Anyone wanting to get a vaccination for themselves or their child can do so at a vaccination center or at any family doctor, pediatric or specialist practice. Company doctors are also allowed to vaccinate employees against COVID-19. It is now also possible to be vaccinated by trained personnel in pharmacies. Mobile vaccination teams are being used in some places.

Points of contact are listed by federal state on the Kassenärztliche Vereinigung (Association of Statutory Health Insurance Physicians) website.

Should people who have recovered from COVID-19 get vaccinated too?

STIKO recommends that people who have previously been infected with SARS-CoV-2 – as demonstrated by a positive PCR test – should receive a one-off coronavirus vaccine dose as primary immunization. According to the recommendation, this should happen 3 months after recovery.

If the infection has been confirmed by a COVID-19 antibody test, the vaccine dose can be administered from as early as 4 weeks after the laboratory diagnosis.

Important: Recovered children with no pre-existing health conditions should not initially receive any further vaccinations. In the case of people with an immune deficiency, a doctor must decide the number of vaccine doses required on a case-by-case basis.

When is it beneficial to get a booster vaccine?

Administration of a booster vaccine comes into play if the immunity provided by primary immunization against COVID-19 declines over time or if the standard vaccination series does not offer sufficient protection.

STIKO recommends booster vaccines for all double-vaccinated people aged 12 years and over, as well as for children aged between 5 and 11 who have a pre-existing health condition. People aged 18 years and over should have their booster from 3 months after their primary immunization; children and adolescents aged 12 to 17 should have theirs after 3 to 6 months. Children and adolescents with pre-existing health conditions should have their booster as soon as possible, whereas those without pre-existing conditions should leave it as long as possible within the recommended period. Children aged 5 to 11 with a pre-existing condition should receive a booster vaccine at the earliest 6 months after primary immunization.

In the case of people who have recovered from a SARS-CoV-2 infection and received a single vaccine dose for primary immunization, STIKO recommends a booster dose from 3 months after the initial vaccine. This recommendation applies to all recovered people aged 18 and above. For people who have recovered from a COVID-19 infection and for adolescents aged between 12 and 17, STIKO recommends an interval of between 3 and 6 months between primary immunization and a booster dose. For younger children, this interval should be at least 6 months. 

Currently, an mRNA vaccine from BioNTech/Pfizer or Moderna is generally given as a booster. 

Who should get a second booster vaccine?

STIKO recommends that certain groups of people should boost their immunity against coronavirus with a second booster dose. These include, for example:

  • people aged 70 and older
  • residents of residential care facilities and people who receive care in care facilities
  • people with disabilities in institutions providing social integration assistance for the disabled who are at an increased risk of developing a severe form of the virus
  • people aged 5 and older who have a weakened immune system
  • staff working in medical and care facilities

At-risk patients should receive a second booster dose 3 months after the first. Staff should receive their second booster 6 months after the first. An mRNA vaccine is used for this purpose.

Important: STIKO does not recommend a second booster vaccine for people who contract a coronavirus infection following a first booster dose.

Further answers to questions about the topic of booster vaccination are available on zusammengegencorona.de, a website provided by the Federal Ministry of Health (BMG).

Where else can I get information from?

For detailed information on the COVID-19 vaccination, visit zusammengegencorona.de, a website provided by the Federal Ministry of Health (BMG).

The website of the Robert Koch Institute (RKI) provides answers to frequently asked questions about COVID-19 and vaccinations.

“Das Impfbuch für alle” (“The Vaccination Book for Everyone”) – a brochure produced by the Robert Koch Institute (RKI) and the Federal Center for Health Education (BZgA) provides detailed information on vaccinations, vaccine research, and COVID-19 vaccinations. It can be obtained for free from pharmacies and online.

People from Ukraine can find essential information about COVID-19 and vaccination in their first language on infektionsschutz.de.

In cooperation with the Robert Koch Institute (RKI). As at:

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