Contraindications to vaccination

Rationale for medical contraindications

Immunization exemption is always based on a thorough assessment of the likelihood of developing severe complications. Physicians identify several categories of conditions that serve as a justified reason for a medical exemption:

• Conditions that complicate differential diagnosis. This group includes pathologies in which it is extremely difficult to determine the true cause of health deterioration or the development of an adverse event if it coincides in time with the post-vaccination period.
• Conditions in which the procedure increases the risk of complications or exacerbates the current pathology. A classic example from neurology: administration of whole-cell or acellular diphtheria-tetanus-pertussis vaccine (DTP/DTaP) to patients with progressive neurological disorders or afebrile seizures of unknown origin. It has been proven that this significantly increases the risk of provoking seizure syndrome. Another example concerns immunity: the administration of live vaccines to patients with immunodeficiency (e.g., HIV-infected) is strictly regulated. Due to the decreased reactivity of the body, the vaccine strain is capable of causing a generalized infection.
• Conditions that independently cause adverse events. These are so-called temporary contraindications, which include acute illnesses or periods of exacerbation of chronic pathologies. In such cases, vaccination is simply postponed until the patient's condition completely normalizes. It is worth noting that temporary contraindications in modern practice are subdivided into two categories, the first of which consists of patient conditions that reliably increase the risk of developing adverse events following immunization.

Modern paradigm of vaccinology

Thanks to the rapid development of clinical immunology, the medical community has radically revised approaches to the immunization of individuals with a burdened anamnesis.

Today, it has been scientifically proven not only that vaccination is safe, but that it is critically necessary not only for absolutely healthy children, but also for patients suffering from various chronic diseases. The list of absolute contraindications to the procedure has been significantly reduced. It is important to emphasize that such a reduction in the list of medical exemptions has not led to an increase in the number of post-vaccination complications.

General and specific contraindications

For ease of memorization and application in clinical practice, within the framework of the National Immunization Schedule, contraindications are divided into general (group) and specific to particular preparations.

General (group) contraindications:

• For absolutely all vaccines: the presence of a severe reaction or severe post-vaccination complication to a previous administration of this specific preparation.
• For all live vaccines: conditions accompanied by a profound immune defect. These include primary immunodeficiencies, drug-induced or other immunosuppression, as well as malignant neoplasms. In addition, live preparations are contraindicated during pregnancy due to the high risk of teratogenic effects of the vaccine strain.

Contraindications to specific vaccines:

• BCG (against tuberculosis): prematurity, if birth weight was less than 2000 g; presence of a keloid scar, including one formed after the administration of a previous dose.
• Live vaccines against measles, mumps, and rubella: severe allergic reactions to aminoglycosides. If the preparation is cultured on chicken embryos, anaphylactic reactions to chicken egg protein serve as a contraindication.
• Hepatitis B vaccine (HBV): allergy to baker's yeast (the restriction is due to the fact that the vaccine is recombinant and produced using yeast cells).
• Influenza vaccines: allergy to chicken egg protein and aminoglycosides, as well as a documented severe reaction to a previous administration of absolutely any influenza vaccine.

Class and exam questions

What else to study on this topic

• The second category of temporary contraindications (not covered in the current material).
• Mechanisms of formation of allergies to aminoglycosides during vaccination.
• Features of the production of recombinant vaccines on yeast cells.
• Management tactics for patients with keloid scars after BCG.

Other topics in "Chapter 1. General Issues"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.