Healthy living Vaccinations: protection against infectious diseases

Vaccinations protect against contagious diseases (infectious diseases) and are therefore sometimes referred to as protective vaccinations. Vaccinations enable many infectious diseases to be prevented and their spread to be restricted or even halted. 

Vaccinations protect against infectious diseases

Infectious diseases are often caused by bacteria or viruses. However, there are also infectious diseases caused by fungi or other microorganisms. The spectrum ranges from mild common colds to serious illnesses such as meningitis, lockjaw (tetanus) or polio (poliomyelitis). The pathogens are transmitted, for example, through direct contact with other people, when handling animals, via the air, or through the shared use of objects such as door handles. 

Many infectious diseases can be prevented through good hygiene measures. A healthy immune system also protects against many pathogens. However, even when the immune system is healthy, some pathogens can cause serious illnesses, such as tetanus. Vaccinations are particularly important for such illnesses, which are associated with a high risk of a serious or death.

Vaccinations restrict the spread of infectious diseases

Vaccinations also often do more than just protect the people who get vaccinated. They can also help to restrict or even halt the spread of the relevant infectious disease, i.e. the transmission of the infection from person to person.

In countries with high vaccination rates, such as Germany, the prevalence of serious infectious diseases such as polio (poliomyelitis), diphtheria and tetanus (lockjaw) has been greatly reduced. According to the World Health Organization (WHO), smallpox was eradicated in 1979 due to a global vaccination campaign. The current aim is to globally eradicate polio. Germany is also trying to use vaccinations to completely eradicate measles.

If people contract pathogens such as bacteria or viruses, the body will try to fight them. The immune system is activated and, among other things, forms antibodies that attach to the pathogens. This enables the body’s own immune cells to recognize and eliminate pathogens marked with antibodies and, in most cases, successfully fight the infection.

Upon repeat contact with the pathogen, the immune system can react far more quickly because the body “remembers” it to a certain extent: it produces the right antibodies more rapidly, enabling it to fight the pathogen faster and more effectively. This explains why people usually only get some infectious diseases such as mumps, rubella and chickenpox once in their lifetime. They are then immune to the disease.

A vaccination works similarly to an initial infection: the immune system learns to identify the pathogen. This enables it to react in a rapid, targeted manner upon renewed contact and to fight the pathogen. Unlike an infection, however, the vaccine does not trigger an illness. Instead, it prevents the disease from developing or, if it is contracted, reduces the likelihood of a severe illness.

Vaccine types

There are various types of vaccines. These have different components but very similar effects.

• Live vaccines: vaccines containing live, significantly weakened pathogens. Examples: vaccines for measles, mumps and rubella.
• Inactivated vaccines: vaccines that contain pathogens or pathogen components that have already been killed. Examples: vaccines for diphtheria, hepatitis B and tetanus.
• Genetic vaccines: vaccines containing the genetic information that provides the blueprint for pathogen components. These include, for instance, mRNA and vector vaccines. Examples: most COVID-19 vaccines.

Primary immunization

Primary immunization refers to the vaccinations required to establish an effective level of protection. This usually involves two or three vaccine doses. A single vaccine dose is rarely sufficient. With some vaccinations, people are protected for life following primary immunization. In the case of others, boosters are required at certain intervals.

Exception: passive immunization

In addition to active immunization through the use of vaccinations, there is also passive immunization. With this, instead of the body being stimulated to produce antibodies against certain pathogens, the appropriate antibodies are administered directly. These antibodies can either be biotechnologically produced or come from people who are already immune to the disease and who have donated antibodies in a plasma or blood donation.

Passive immunization can quickly protect against pathogens and prevent a disease from developing. It is used, for example, if people are suspected of having been exposed to a dangerous pathogen, such as the rabies virus or the bacterium that causes tetanus and are not sufficiently immunized against the disease. Even with COVID-19, antibodies are sometimes used to prevent the disease or reduce the risk of severe illness.

Important: unlike vaccinations, the administration of antibodies works extremely quickly but the protective effect is not as long-lasting. 

There are many infectious diseases that can now be avoided through vaccinations.

Germany has an independent expert body, the Ständige Impfkommission (STIKO – Standing Committee on Vaccination), which continuously evaluates current scientific evidence and makes vaccine recommendations for Germany.

It should be noted that some vaccinations are only recommended for specific age groups or groups of people because they can particularly benefit from them. For example, some people may have a chronic health condition that puts them at increased risk of having a severe illness.

The STIKO currently recommends standard vaccinations against the following illnesses: 

• diphtheria
• tetanus (lockjaw)
• whooping cough (pertussis)
• polio (poliomyelitis)
• hepatitis B
• measles
• mumps
• rubella
• chickenpox (varicella)
• shingles (herpes zoster)
• flu (influenza)
• COVID-19
• haemophilus influenzae type B infections
• human papillomavirus (HPV) infections
• pneumococcal infections
• meningococcal infections
• rotavirus infections
• respiratory syncytial virus (RSV) infections

Most standard vaccinations should be administered during childhood. Some require two to three booster vaccines during adolescence to provide lifelong protection. These include vaccinations against tetanus, diphtheria, whooping cough and polio.

Other vaccinations are only recommended as standard for older people. These include the shingles vaccine, for example. In addition, there are certain standard vaccines, such as the flu vaccine, that should be administered every year. 

Further information about vaccination and a vaccination calendar can be obtained from the website impfen-info.de, operated by the Federal Institute for Public Health (Bundesinstitut für Öffentliche Gesundheit, BIÖG).

Measles immunization and mandatory vaccination

Measles is a highly contagious disease that is primarily transmitted by droplets suspended in the air. Complications and secondary diseases are common. Vaccination protects against measles and prevents the disease from spreading.

Almost all vaccinations are solely subject to recommendations, i.e. people can independently decide whether they want to vaccinate and protect themselves or their child.

The measles vaccination is an exception: the Measles Protection Act (Masernschutzgesetz) has been in force since March 2020 and stipulates that anyone born after 1970 who is cared for or works in a community facility or who works in a medical facility must provide proof of vaccination against measles.

Alternatively, such people can provide a medical certificate that shows sufficient immunity against measles. People who have already had measles can provide such a certificate, as a measles infection provides lifelong immunity.

The Measles Protection Act aims to protect people against measles who could not (yet) be vaccinated, for example in the case of infants or people with an immunodeficiency. In the long-term, measles should be completely eradicated through a high vaccination rate – as is already the case with smallpox.

Further information about measles and the Measles Protection Act can be found at masernschutz.de, a website operated by the Federal Institute for Public Health (Bundesinstitut für Öffentliche Gesundheit, BIÖG).

In addition to the standard vaccinations, there are also other vaccinations (indicated vaccinations) that are recommended under certain circumstances:

• an increased occupational risk: for example the vaccination against hepatitis A for healthcare professionals
• increased personal risk: for example vaccinations against pneumococcal and meningococcal bacteria for people with certain pre-existing conditions such as an immunodeficiency
• travel to high-risk areas: for example vaccinations against cholera, yellow fever and rabies
• residence in high-risk areas: in Germany, this is particularly relevant with regard to the vaccination against tick-borne encephalitis (TBE)
• specific risk situations such as epidemics and pandemics: for example, vaccination against COVID‑19 – this is now considered a standard vaccination.

Information about travel vaccinations can be obtained from doctors and specialists in travel medicine. The Foreign Office (Auswärtiges Amt) also provides information about vaccination options when traveling abroad.

Information about TBE vaccination and the current high-risk areas can be found at impfen-info.de, a website operated by the Federal Institute for Public Health (Bundesinstitut für Öffentliche Gesundheit, BIÖG).

Some infectious diseases can be more serious for pregnant women or can harm the unborn child. To protect themselves and their child, women should therefore ideally have all recommended vaccinations prior to pregnancy. This particularly applies to live vaccines, such as those for chickenpox, measles and rubella. This is because these vaccines are not allowed to be administered during pregnancy.

On the other hand, vaccinations against flu (influenza) and whooping cough (pertussis) are particularly recommended during pregnancy. These are inactivated vaccines that do not pose any risks to the child. The flu vaccine protects pregnant women, who are at increased risk of becoming seriously ill with flu during pregnancy. Vaccination against whooping cough (pertussis) from the second trimester can provide unborn babies with “nest protection”, protecting them against whooping cough for the first few months of life until they themselves can be vaccinated.

Vaccinations are classed as extremely safe. There are several reasons for this: All vaccines placed on the market in Germany must first undergo an extensive authorization procedure. This involves the responsible authorities checking the data on the vaccine’s quality, efficacy and safety. The Paul Ehrlich Institute (PEI) is responsible for this role in Germany and the European Medicines Agency (EMA) at European level.

Following the authorization, the Paul Ehrlich Institute verifies the quality of every batch of vaccines produced prior to their placement on the market, and clears every single batch for marketing in Germany. A legally regulated reporting system also ensures that suspected side effects can be collated and evaluated by the PEI. This makes it possible to detect potential, previously unknown risks and side effects at an early stage.

How well-tolerated are efficacy enhancers in vaccines?

Some inactivated vaccines contain, for example, aluminum compounds as adjuvants (efficacy enhancers) in order to sufficiently activate the immune system and develop effective protection.

Adjuvants are used in vaccines against tetanus, diphtheria, and whooping cough, for instance. They are needed because those vaccines only contain killed pathogens or parts of them, which on their own do not sufficiently stimulate the immune system.

The aluminum compound content in vaccines approved in Germany and Europe is less than the maximum specified by the European Pharmacopoeia. The amount of additional aluminum compounds taken in through vaccines is minimal in relation to the daily absorption through the air, drinking water and food.

The tolerability of the vaccines, including the efficacy enhancers, is also assessed very precisely during the authorization procedure. The safety of the vaccine is also continually monitored following the authorization.

What is a vaccination reaction?

A mild physical reaction to a vaccine is known as a vaccination reaction. This is a natural, harmless reaction that normally disappears within a few days. Typical post-vaccination issues include reddening, swelling and pain at the injection site.

Examples of general reactions after vaccinations include a high temperature, headache and limb pain, nausea, and diarrhea. When live vaccines are used, for example against measles, mumps or rubella, mild symptoms that resemble the relevant illness may occasionally appear after the vaccination. However, they are not comparable with the real illness and the person concerned is not infectious.

Can serious side effects occur?

In recent decades, vaccinations have become more and more tolerable, so that serious side effects only occur very rarely. Examples of these include severe allergic reactions, febrile seizures in children or bowel obstructions after rotavirus vaccinations.

Information on how to report suspected side effects can be found on the website of the Paul Ehrlich Institute (PEI).

What considerations are required for people with an egg allergy?

Some vaccines may contain low traces of egg protein (albumen), as they are produced in hen’s eggs. These include vaccines against yellow fever and some flu vaccines. These vaccines should not be administered to anyone who has a severe egg allergy. 

Other vaccines, such as those against mumps, measles and rubella, contain such small traces of albumen that they are barely detectable. Most people with an egg allergy can still be safely vaccinated with such vaccines.

Anyone with questions about immunization in general or about specific vaccinations can speak directly to a doctor. There are also reliable online sources with a wide range of information. These include:

the Federal Institute for Public Health (BIÖG): impfen-info.de

the Federal Ministry of Health (BMG): Vaccinations

the Paul Ehrlich Institute: Vaccines for Humans

the Robert Koch Institute: Immunisation

When traveling abroad:

the Foreign Office (Auswärtiges Amt)