Australia, officially known as the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. It is the largest country in Oceania and the world’s sixth-largest country by total area.
Singapore, officially the Republic of Singapore, is a sovereign island city-state in maritime Southeast Asia.
The country’s territory is composed of one main island, 63 satellite islands and islets, and one outlying islet, the combined area of which has increased by 25% since the country’s independence as a result of extensive land reclamation projects. It has the second greatest population density in the world. The country has almost 5.7 million residents, 61% (3.4 million) of whom are Singaporean citizens. There are four official languages of Singapore: English, Malay, Chinese, and Tamil; with English being the lingua franca.
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 killed forms of the microbe, its toxins, or one of its surface proteins.