Measles: the war on childhood plague continues
Thanks to routine immunization, we managed to forget about the many incredibly contagious and dangerous diseases. Nevertheless, it’s too early to relax: if group immunity decreases due to refusal of vaccination, terrible epidemics can return, and these are not just words. In 2018, the media anxiously reported frequent cases of measles, or the “childhood plague,” as it is called. In this article of the “Vaccination” special project, we will tell you why measles is dangerous, how to deal with it, and why it is still not defeated.
The invention of vaccines has radically changed the life of mankind. Many diseases that claimed thousands, or even millions of lives annually, are now almost never encountered. In this special project, we not only talk about the history of vaccines, the general principles of their development and the role of vaccine prevention in modern healthcare (the first three articles are devoted to this), but we also talk in detail about each vaccine included in the National vaccination calendar, as well as flu vaccines and human papillomavirus. You will learn about what each of the causative agents of the disease is, what vaccine options exist and how they differ, and we will touch upon the topic of vaccine-related complications and the effectiveness of vaccines.
Measles is an incredibly contagious disease
Measles is a highly contagious viral disease. This statement clearly illustrates the case that occurred in Indiana (USA) in 2005. Then the unvaccinated seventeen-year-old girl returned home from Romania, where measles outbreaks raged. Still on the way, her temperature rose, a cough and runny nose began, her eyes turned red. However, despite her malaise, the next day she went to a church picnic, where there were 500 people.
It should be noted that in the USA, measles was considered a rarity by that time, and the vaccination level of the population was very high. Only 35 guests at the picnic were never vaccinated against measles, and 31 of them (89%) were infected by the girl. Of the remaining 465 people, only three were infected (0.6%). A girl who became ill in Romania spent only a few hours in a crowd of five hundred people, and almost all people susceptible to this disease caught the virus , . This story shows how contagious the measles virus is – it circulates even where most people are vaccinated. It is instructive here that a vaccine-protected society is at risk of a disease that has migrated from another country.
Unfortunately, outbreaks of measles, such as in Indiana or even much more serious (in 2008, the new measles epidemic in America affected not just one state, but as many as 13 ), have little effect on the public. At the same time, a lot of myths are concentrated around the danger of measles vaccines themselves, deeply rooted in the minds of people. As a result, measles continues to attack worldwide until now, and parents are increasingly refusing to vaccinate their children, weakening the protection of not only their families, but also entire cities and even countries.
It is important to understand that the more contagious the disease, the greater the percentage of people who need to be vaccinated in order to prevent new epidemics. To protect against such an infectious disease as measles, the level of immunization should be about 95% . This figure is not accidental: it is based on a study of the rate of development of the virus, depending on the level of immunity in the population. The significance of the widespread spread of measles vaccines is easily appreciated by looking at the visualization (video 1) created using the FRED (Framework for Reconstructing Epidemiological Dynamics) computer simulation system. This system was invented and implemented by the University of Pittsburgh Public Health Dynamics Laboratory in collaboration with the Center for Pittsburgh Supercomputers and the Carnegie Mellon University School of Computer Science. FRED mimics the spread of an infectious disease, given the potential for transmission of a virus in a city or county in the United States, as well as in several other countries. A virtual measles epidemic begins with one sick school-age child and lasts seven months. Events can develop in two scenarios. In the first case, 80% of children aged from six months to 15 years old were vaccinated against measles, in the second – 95%. For most cities, the difference in epidemic development in the two scenarios is enormous.