Vaccines

Products

Vaccines are mainly sold as injectables. Some are also taken perorally as oral vaccines, for example, in the form of capsules (typhoid vaccine) or as a suspension for oral administration (rotavirus). Monopreparations and combination preparations are commercially available. Vaccines, with few exceptions, are stored in a refrigerator at a temperature of 2 to 8 °C. Vaccines are among the most important medicines in the history of mankind. They save the lives of millions of people every year and prevent untold suffering. Vaccines protect against disease, its complications and disabilities. They also have economic benefits, reducing the burden on health care, protecting the economy, and improving the quality of life. The pioneer in this field was Edward Jenner, an English physician who developed the smallpox vaccine and first administered it at the end of the 18th century in 1796.

Structure and properties

Vaccines belong to the group of biologics. They contain attenuated pathogens, single or multiple components (proteins, polysaccharides) of the pathogens, or nucleic acids that code for them. The most important groups are shown below: Live, attenuated pathogens:

  • Live vaccines, e.g., the MMR vaccine, chickenpox.

Inactivated vaccines:

  • Inactivated pathogens, for example, the hepatitis A vaccine and TBE vaccine.
  • Split vaccines (split vaccines), produced with detergents.
  • Subunit vaccine contain purified parts of the pathogen, for example, the vaccine against whooping cough.
  • Inactivated toxins (toxoid vaccines), e.g. DTPa-IPV+Hib vaccine.
  • Conjugate vaccines, e.g. Haemophilus influenzae type b, pneumococci, meningococci.
  • Recombinant vaccines, e.g. hepatitis B vaccine, HPV vaccine.

Nucleic acids (in many countries since 2020):

Vaccines contain various excipients such as adjuvants (eg, aluminum salts), preservatives, salts, stabilizers and water for injection. Furthermore, residues of the production process such as traces of antibiotics may be present. Vaccines approved in many countries do not contain mercury compounds such as thiomersal.

Effects

The principle of vaccines is to present antigens of pathogens to the immune system, which it recognizes as foreign and initiates the immune response. Through the formation of memory B and T cells, the immune system is able to recognize the pathogen in the event of infection and eliminate it with the help of specific antibodies and immune cells, among others. Vaccination protection is usually very high, ranging from 90 to 100%. It does not occur immediately after vaccination, but with a time delay. Vaccinations are not only for self-protection. They also protect people in the environment, prevent transmission and block chains of infection. Risk groups include the elderly, people with chronic diseases, immunosuppressed persons, pregnant women and infants. So-called herd immunity protects non-immunized people from infection.

Indications

For prevention of infectious diseases, mainly with bacteria and viruses. Vaccines are also being developed against parasites and fungi. Vaccinations are recommended to different target groups. The Federal Office of Public Health publishes the Swiss Vaccination Plan. It contains all the relevant recommendations. Vaccines are also developed for the prevention and treatment of other diseases, for example, cancer, addiction, and autoimmune diseases.

Dosage

According to the SmPC. Vaccines are usually administered as an intramuscular injection, typically in the deltoid muscle of the upper arm. Intramuscular injection is also possible in the outer thigh and buttock (gluteal muscle), depending on the active ingredient. Some vaccines may also be injected subcutaneously. Intravenous administration, on the other hand, is not permitted. In addition, other methods of administration exist for some vaccines, for example peroral or intranasal administration. As a rule, a single dose is not sufficient to ensure adequate protection. Therefore, two or more administrations are often required at intervals that may be weeks, months or years apart.With a booster vaccination, the vaccination protection can be renewed after years. For example, it is necessary for TBE prevention after 10 years. The flu vaccination must be renewed every year because the virus is constantly changing and the immune system no longer recognizes it.

Diseases and representatives (selection)

The following are diseases and agents against which vaccination can be given.

  • Cholera
  • Covid-19, see under Covid-19 vaccines.
  • Diphtheria, see under DTPa-IPV-Hib vaccine.
  • Ebola
  • TBE, see under TBE vaccination
  • Cervical cancer, see under HPV vaccination.
  • Yellow fever
  • Influenza, see under flu vaccination
  • Shingles
  • Haemophilus influenzae type b, see under DTPa-IPV-Hib vaccination.
  • Hepatitis A, see under Hepatitis A vaccination.
  • Hepatitis B, see under hepatitis B vaccination.
  • Japanese encephalitis
  • Whooping cough (pertussis), see under DTPa-IPV-Hib vaccination.
  • Polio (polio), see under DTPa-IPV-Hib vaccination.
  • Pneumonia, pneumococcal
  • Measles, see under MMR vaccination
  • Meningococcal
  • Anthrax
  • Mumps, see under MMR vaccination
  • Plague
  • Rotaviruses
  • Rubella, see under MMR vaccination
  • Tetanus, see under DTPa-IPV-Hib vaccination.
  • Rabies, see under Rabies Vaccination.
  • Tuberculosis
  • Typhoid fever, see under typhoid vaccination
  • Chickenpox, see under chickenpox vaccination

Contraindications

Contraindications include, depending on the vaccine:

  • Hypersensitivity to the active ingredients, excipients and impurities.
  • Pregnancy, lactation
  • Immunosuppression, treatment with immunosuppressants and cytostatic drugs.
  • Acute, febrile diseases, for example, the flu.

Appropriate medical treatment and monitoring must be available if a severe hypersensitivity reaction occurs. Full precautions can be found in the drug label.

Interactions

Immunosuppressants may reduce vaccine protection. Immunosuppressed patients should not receive live vaccines. Some vaccines may be given concurrently.

Adverse effects

The most common possible adverse effects include transient discomfort such as:

  • Reactions at the injection site, such as pain, redness, swelling, induration
  • Headache
  • Muscle and joint pain
  • Flu-like symptoms, feeling sick.
  • Fatigue
  • Indigestion such as diarrhea, nausea.
  • Skin rash

Paracetamol, for example, can be used for treatment. Extremely rare are severe side effects such as anaphylaxis or diseases of the central or peripheral nervous system such as Guillain-Barré syndrome. However, the benefits of vaccines far outweigh the risks. Vaccines do not cause autism.