vakcinaci

Vakcinace, or vaccination, is a medical intervention designed to prevent infectious diseases by training the immune system to recognize and fight specific pathogens without causing illness. Vaccines introduce antigens from the target pathogen, inactivated organisms, or instructions for cells to produce antigen, triggering an adaptive immune response and the development of memory B and T cells.

Historically, vaccination began with smallpox variolation and Jenner’s cowpox vaccine in the late 18th century. Since then, vaccines have dramatically reduced the burden of diseases such as polio, measles, and tetanus and enabled the partial or complete elimination of several illnesses in different regions through routine immunization programs and herd immunity.

Vaccine types include live attenuated, inactivated, subunit or protein, toxoid, conjugate, viral-vector, and nucleic acid (mRNA/DNA) vaccines. Formulations vary by route of administration and may use adjuvants to enhance the immune response or delivery platforms to improve efficacy and stability.

Development follows preclinical testing and phased clinical trials (Phase I–III), regulatory review, and licensing, followed by post-marketing safety monitoring. Most vaccines cause mild, short-lived side effects; serious adverse events are rare, and risk–benefit analyses guide public health recommendations.

Public health impact is substantial: vaccines prevent illness, hospitalizations, and deaths and support healthy communities. Challenges include ensuring global access, maintaining cold chains, and countering misinformation that affects uptake.