Measles is spreading across continents now. For now it had spread in Texas and New Mexico, now Australia too has reported surge of the same infectious disease. The disease is highly contagious, even more than Ebola, smallpox or any other disease you may have heard of. One sick person can infect up to 18 people with measles. Whereas the number of people who can be infected from one person in other infectious disease is low. For instance, if one person is sick with Ebola, he can at maximum infect two people, for COVID-19, it is three people; for HIV, SARS, the number is four. Diseases like chickenpox and mumps have greater number, 12 and 14 people respectively, however, the highest number of people who can be infected by a disease from one person is measles, as per The Lancet, University of Michigan School of Public Health and Journal of Theoretical Biology's data. Highly Infectious, Highly LethalBefore the invention of vaccination, which helped eliminate the disease in the US, almost everyone in childhood got measles. Not only that, but, 400 to 500 children had also died from the same each year. However, it was the vaccination that was able to beat the measles outbreak. The concern now is the drop in vaccination rates, which could beat back the elimination of the disease from the United States. How Does It Spread?Scientists use a concept called reproduction manner or the R naught to see who quickly a disease spreads. This is also the number of people, on average, that a single infected person can transmit a disease to.For measles, the R naught is 12 to 18, which is higher than with other infectious disease. However, it is still a theoretical number and like Justin Lessler, an epidemiologist at the University of North Carolina Gillings School of Global Public Health says, "It is not some magical constant."This concept assumes that no one has immunity to a given disease, this is what the "naught" refers to, which means zero. It helps scientists compare the infectious potential of different diseases, however, the concept may differ depending on various factors, including how easily measles of any other disease transmits and alters the process.ALSO READ: Measles FAQs: What You Must Know About The Disease Then comes the concept of effective reproduction number. This is the number of people that a sick person can infect in a given population at any specific time. This changes as more people become immune through infection or vaccination. This also changes based on how people react or behave towards a new infectious disease? Do the isolate? Do they cluster together and socialize? These scenarios can then give an opportunity for the virus to exist. Thus this concept depends on how the community reacts to deal with the virus. The Power Of VaccinesHowever, all of this could be beaten with the help of vaccination. Depending on the vaccination rate, one person can infect around 12 to 18 people in case there has been 0% vaccination. If 67% of the population is vaccinated, only 5% people would be infected. If 82% of the population is vaccinated, only 2 to 3 people would be infected. Lastly, the Centers for Disease Control and Prevention (CDC) also notes that if 95% of the population is vaccinated, there will be fewer than one case of measles.READ MORE: Measles Outbreak Cases Cross 100 Mark In US, Australia Sees Sudden Surge Of The Infectious Disease