WHAT IS A VACCINE?

Franca Daniele, MD,
“G. d’Annunzio” University, Chieti-Pescara, Italy

To date Covid-19 is still spreading easily and sustainably all over the world. The covid-19 pandemic has certainly lead many policy makers in many countries to revise and reset their healthcare systems in terms of both human resources and facilities, and today all countries are striving for vaccines. What is a vaccine? The term vaccine derives from the Latin word for cow – vaccà, vaccae. The corresponding adjective and adverb is vaccinae meaning – having to do with cow, ‘cowly’, ‘cowish’. Edward Jenner in 1798 developed the term, and the first vaccine was inoculated in cows infected with Variola Virus, from which the name of the first vaccine was derived – Variolae vaccinae  (smallpox of the cow – cowpox). The vaccine was later administered also to people infected with Variola Virus, suffering from smallpox (Jenner, 1800). Later, Louis Pasteur in 1881, proposed to extend the term ‘vaccine’ to all the protective inoculations against viruses (Pasteur, 1881).

Vaccines are chemical preparations that provide active acquired immunity against either a single specific virus (monovalent) or against a group of viruses (polyvalent) (Sakhatskyy, 2006). Vaccines are normally biological preparations often made from either weakened or killed forms of the virus or some of its components. The agent stimulates the immune system of the body to recognize it as a threat (non-self) and starts producing antibodies against it. In this way the immune system is capable of further recognizing and destroying any of the microorganisms associated with that agent that it may encounter in the future. Vaccines can be either prophylactic – to prevent or improve the effects of a future infection by a natural or ‘wild’ pathogen, or therapeutic – to fight a disease that has already occurred, such as cancer (WHO, 20202; Bachmann and Dyer, 2004). Vaccination is the most effective method of preventing infectious diseases (Brotherton, 2015); widespread immunity due to vaccination is largely responsible for the worldwide eradication of smallpox and the restriction of diseases such as poliomeasles, and tetanus from much of the world. The effectiveness of vaccination has been widely studied and verified (Frazer, 2014). 

 

Bachmann M. and Dyer M. (2004) Therapeutic vaccination for chronic diseases: a new class of drugs insight. Nat Rev Drug Discov 3, 81–88. https://doi.org/10.1038/nrd1284

Brotherton J. (2015) “HPV prophylactic vaccines: lessons learned from 10 years experience”. Future Virology10 (8): 999–1009. doi:10.2217/fvl.15.60.

Jenner E. (1800) Dr. Jenner, on the Vaccine Inoculation. Med Phys J. 3(16):502-503.

Sakhatskyy P., et al. (2006) Immunogenicity and protection efficacy of monovalent and polyvalent poxvirus vaccines that include the D8 antigen,Virology, Volume 355, Issue 2, Pages 164-174, ISSN 0042-6822, https://doi.org/10.1016/j.virol.2006.07.017.

WHO (2020) Prophilactic Vaccines https://www.who.int.

Frazer I.H. (2014) Development and implementation of papillomavirus prophylactic vaccinesJournal of Immunology. 192 (9): 4007-11. doi:10.4049/jimmunol.1490012PMID 24748633.

Pasteur L. (1881). “Address on the Germ Theory”. Lancet. 118(3024): 271–72. doi:10.1016/s0140-6736(02)35739-8.

 

 

                                                                                    Franca Daniele, MD

“G. d’Annunzio” University Chieti-Pescara

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