Infectious diseases are illnesses caused by pathogenic microorganisms such as bacteria, viruses, parasites, or fungi that can be transmitted from one person to another directly or indirectly (vector-borne). Infection is the penetration of pathogens into body tissues, their multiplication, and the reaction of host tissues to the infectious agents and toxins they create. An infectious disease, often known as a vector-borne or contagious disease, is a condition caused by an infection. Infections are caused by a variety of pathogens, the most common of which are bacteria and viruses. The immune system of hosts can help them fight off disease. Mammalian hosts respond to infections with an innate, usually inflammatory response, followed by an adaptive response. Infectious disease refers to the branch of medicine that deals with infections.
Vaccination is a simple, safe, and effective way to protect against deadly diseases before they infect you. It strengthens your immune system by using your body’s own defenses to build resistance to certain pathogens. Vaccines teach your immune system to produce antibodies in the same way it does when you are exposed to a disease. Vaccines, on the other hand, do not cause illness or put you at risk for complications because they contain only killed or weakened forms of pathogens such as viruses or bacteria.Vaccines interact with your body’s natural defenses to create protection, reducing your risk of contracting a disease. Your immune system responds when you receive a vaccine. As a result, vaccination is a smart and safe technique to induce an immune response in the body without causing disease. Our immune system is programmed to memorize information. Typically, after receiving one or more doses of a vaccine, we are protected from disease for years, decades, or even a lifetime.