Vaccines, Vaccination, and Vaccinology

- Overview

Vaccines have transformed public health, especially since national immunization programs were first properly established and coordinated in the 1960s. In countries with high coverage of vaccine programs, many diseases that previously killed most children have largely disappeared. The World Health Organization (WHO) estimates that current immunization programs save 2–3 million lives per year, helping to reduce the global under-five mortality rate significantly from 93 per 1,000 live births in 1990 to 39 Deaths per 1,000 live births in 2018.

Vaccines exploit the remarkable ability of the highly evolved human immune system to respond to and remember encounters with pathogen antigens. However, for most of history, vaccines were developed through empirical research without the involvement of immunologists. A better understanding of the immunological basis of vaccination is greatly needed today to develop vaccines against difficult-to-target pathogens such as Mycobacterium tuberculosis, the bacterium that causes tuberculosis (TB), and antigenically variable pathogens such as HIV, which control Outbreaks that threaten global health security, such as COVID-19 or Ebola virus, and study how to restore immune responses in aging immune systems to protect the growing elderly population from infectious diseases.

- Vaccines

Vaccines are biological agents that provide active adaptive immunity against specific diseases. Vaccine development involves the use of disease-causing microorganisms, either in killed or attenuated form, or the use of toxins or surface proteins of microorganisms. Vaccines are given by mouth, injection or nasal route to prime the immune system to fight foreign substances.

During the development of immunity, the body produces antibodies against specific microorganisms, thus creating a defense mechanism. When a person later encounters the same microbe, the body produces antibodies in response to the microbe's antigens, preventing that person from developing a disease caused by the microbe or reducing the severity of the disease. 

Generally speaking, vaccines are considered the most economical health care interventions, it says "a dollar spent on childhood vaccinations not only helps save lives, but also significantly reduces future health care expenditures".

- Vaccination

Vaccination against infectious diseases such as diphtheria, capsular group C meningococcus, polio, Haemophilus influenzae type b, measles and whooping cough has led to significant reductions in their incidence. Notably, an increase in reports of Haemophilus influenzae type b in 2001 sparked a catch-up vaccination campaign, and incidence has declined since then. For whooping cough, declines in vaccine coverage in the late 1970s and 1980s led to an increase in cases, but the incidence declined again after vaccine coverage increased. Adapted with permission from the Green Book, Immunization information for public health professionals, Public Health England, contains public sector information licensed under the Open Government License v3.0.