It is now more than a year since Novel Coronaviruses are a family of viruses that cause illness of Severe Acute Respiratory Syndrome was identified and reported for the first time in the city of Wuhan, China (1). Since then the disease has affected 221 countries and territories globally and the number of infected people and death toll are increasing every day. Till the end of February 2021, it caused 112,129,723 infections and 2,481,435 deaths all over the world. Though several virological, epidemiological and clinical researches have been conducted and understanding of COVID-19 is evolving, a lot more remained unknown about the virus.Where exactly SARS-CoV-2 came from? It is established that the virus emerged at an animal market in Wuhan, China. This virus called Sars-CoV-2, is closely related to viruses that infect bats. Sars-CoV-2 is assumed that it passed from bats to a mystery animal species and then to people. That "missing link" remains unknown, and could be a source of further infections.How Sars-CoV-2 spread? Though it is confirmed that the virus could spread from person-to-person, there's still debate over exactly how that happens.Varied clinical features: Clinical manifestations of COVID-19 cases varied among same or different group of people. It causes a mild infection for most and severe disease for some. It is not well explained why it affects some people more than others. A person’s age and preexisting medical conditions are risk factors for more severe disease, and men appear to be at higher risk than women (SN: 4/23/20). But scientists don’t have many answers to explain the wide variety of experiences people have with SARS-CoV-2, the coronavirus that causes COVID-19. Many people have no symptoms. Some struggle to breathe, suffer strokes, or progress to organ failure and death.How long might immunity last? After a person acquires a virus, the immune system retains a memory of it. Similarly, people who had COVID-19 have been found to have humoral and cellular immunities. However, specifics about what this means for the immune response and how long immunity lasts are not clear.New Variants: It is normal for viruses to evolve over time through mutations. Likewise, besides the originally and primarily reported SARS-CoV-2 virus, three more variants are identified globally. These new variants include SARS-CoV-2 (known as 20I/501Y.V1, VOC 202012/01, or B.1.1.7) emerged in United Kingdom; SARS-CoV-2 (known as 20H/501Y.V2 or B.1.351) emerged in South Africa and another variant of SARS-CoV-2 (known as P.1) identified in Brazil. But, we do not know if many more variants are still circulating globally especially in low- and middle-income countries where diagnostic capacity is limited. Additionally, we do not know whether the already licensed vaccines are effective against these new variants.The efficacy of vaccines: Although COVID-19 vaccines are found safe and effective in protecting people from getting sick, we are still uncertain whether the vaccines could prevent the spreading of the virus to others.What are confirmed and helpful in limiting the spread of these virus are community sensitization and mobilization, physical distancing measures, hand washing, case tracing and detection.