CityNews Channel on Youtube shows that as Canada continues to endure a fourth wave of COVID-19, the federal government is implementing new vaccine requirements for travellers and federal servants. Nigel Newlove reports.
What is a "vaccine" is interesting. A vaccine is a biological preparation that provides active acquired immunity to a particular infectious disease. A vaccine typically contains an agent that resembles a disease-causing microorganism and is often made from weakened or certain killed forms of the microbe, its toxins, or one of its surface proteins. The agent stimulates the body's immune system to recognize the agent as a threat, destroy it, and to further recognize and destroy any of the microorganisms associated with that agent that it may encounter in the future. So-called Vaccines can be prophylactic (to prevent or ameliorate the effects of a future infection by a natural or "wild" pathogen), or therapeutic (to fight a certain disease that has already occurred, such as cancer). Some certain vaccines offer full sterilizing immunity, in which dangerous infection is prevented completely.
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