More than 140 children have been removed from their classes at schools in Washington because they could not prove they have had the required vaccinations. Health experts in the US have warned the country is in danger of being gripped by a measles pandemic because a growing number of people are not getting vaccinated against the virus and are being exposed to the rest of the population. The virus has swept several states in America and California and officials have warned there could be a danger of reversing the eradication of measles 15 years ago. They are also keen to prevent a return to the outbreak of 1989 when more than 100 people died. Scroll down for video . More than 100 pupils have been kicked out of their classes because they did not have completed vaccination forms, as health officials have warned about the danger of the spread of the measles virus (pictured) This week 143 pupils were removed from their classes in Spokane because they could not prove they had legally required vaccinations, which includes measles. And officials predict the number of children being kicked out of school in the state for not getting their jabs is likely to rise, as around 700 students in the district lack complete documents. Earlier this year, Tom Frieden, director of the Centers for Disease Control and Prevention, said he was concerned about the possibility of a large measles outbreak in America. He said there was concern over the growing number of people choosing not to have their injections to prevent the highly infectious disease and has called for more people to be vaccinated . In February around 100 people were diagnosed with the virus across 15 states. Last month officials in California confirmed 119 people had been diagnosed with measles after visiting Disneyland in Anaheim. The outbreak is believed to have started when an overseas tourist with measles visited the theme park. American officials are calling for children to be vaccinated against measles in order to prevent a pandemic . Spokane school district officials are believed to be the first to remove children from schools in a bid to prevent the spread of measles. District spokesman Kevin Morrison said: 'We're the front-runners . 'Given the increased awareness that the world has of the possibility of pandemic, I think heightened awareness is certainly not a bad thing.' Mr Morrison said complete documentation is important to protecting students so that if there was an outbreak at school staff would know which students to send home. Measles is a highly infectious disease that is characterised by a rash, runny nose and fever. In extreme cases it can be fatal. Children are routinely protected against the virus through the measles, mumps and rubella vaccine but some parents choose not to allow their children to have the jab because they personally disagree with it or due to problems with their offspring's immune system. Dr Tom Frieden, director of the Centers for Disease Control said the spread of measles could increase because of a growing number of people who have not been vaccinated being exposed to the population . Pupils in Spokane were removed from school on Monday and will be allowed to return once their parents either get the required vaccinations, or sign waivers saying they were opposed to one or more vaccinations, Mr Morrison confirmed. The Spokane district has about 30,000 students, and only about 729 students lack the required documentation. Mr Morrison did not speculate on whether other school districts in the region or the state would follow. After the measles outbreak, Spokane district officials discovered about six percent of their students lacked proper vaccination documentation. In February they launched a program to inform parents that their children needed vaccinations or waivers. The school district and the Spokane Regional Health District also held a series of vaccination clinics. This helped reduce the lack of compliance to around three per cent. According to the Centers for Disease Control and Prevention, measles is a highly contagious virus that lives in an infected person's nose and throat mucus and spreads through coughing and sneezing. The CDCP warned: Measles virus can live for up to two hours on a surface or in an airspace where the infected person coughed or sneezed. 'If other people breathe the contaminated air or touch the infected surface, then touch their eyes, noses, or mouths, they can become infected.' Symptoms of measles include fever, cough, runny nose and red eyes and a red rash that usually first appears on the face and spreads to the rest of the body. The infection can lead to blindness and even death. Children aged one to four are most vulnerable. The CDPH warned medics to ask patients if they have either travelled to areas with a measles problem or locations domestically with a large number of foreign tourists from infected areas. The process of ensuring students are vaccinated is complicated because 60 different languages are spoken by students in the Spokane district, and about 30 percent of the students leave their school each year. Tracking vaccinations is especially difficult for students who come from out-of-state or other countries. At least 92 percent of the population of America is vaccinated. However, the number of children who are not vaccinated, is higher in some states, particularly in California where a number of cases are believed to have originated. The virus from Disneyland has so far infected 94 people in eight states, and 67 can be clearly linked to the theme park, health officials reported. It is believed to be linked to a similar outbreak in the Philippines. In California an estimated eight per cent of kindergartners fail to get the required immunizations against measles, mumps and rubella. Some people choose not to get their children vaccinated for personal reasons, or it may be because their immune system is compromised. Children under one year old are not vaccinated because their bodies cannot cope with the vaccine. The issue of vaccination against measles is a historically controversial one. In a 1998 UK study the triple MMR vaccine was linked to autism, causing parents to panic and refuse to get their children vaccinated - leading to a rise in cases and resulting deaths and permanent injuries. However this paper by Andrew Wakefield was partially withdrawn from the Lancet in 2010 and fully retracted in 2014 after it was proven to be fraudulent. Wakefield was found guilty of serious  professional misconduct and was struck off the register. His claims have been disproved by a number of scientific studies. Last week Robert Kennedy Jr waded into a debate about proposals to remove the rights of parents to refuse to get their children vaccinated by comparing it to the holocaust. He claimed there was a link between autism and thimeresol, an ingredient in vaccines, and said: 'This is a holocaust, what this is doing to our country.' Multiple studies have rejected this link and this week Kennedy apologised for his comments.
Pupils in Spokane, Washington, were removed from classes on Monday . A total of 143 were kicked out of school because they did not have documents to prove they have had legally required vaccinations . Officials decided to act after spread of the measles virus in America . Experts have warned there is a danger of a pandemic as people who have not been vaccinated are being exposed to the rest of the population .