Recent study data showing that the outbreaks in Texas cities; which is increasingly susceptible to large measles outbreaks. The growing number of children arriving at Texas schools unvaccinating making the state increasingly vulnerable to measles outbreaks in cities large and small; according to a computer simulation.
But additional 5% decrease in vaccination rates, which have been on a downward trend since 2003; would increase the size of a potential measles outbreak by up to 4,000% in some communities. At current vaccination rates; there are a significant chance of an outbreak involving more than 400 people right now in some Texas cities.
Measles is a highly contagious virus that can cause severe complications, including pneumonia, brain swelling and deafness. Approximately 1 out of every 1,000 children infected with measles will die from respiratory and neurologic complications. Measles is so contagious that, if no one was immunized, one infected person is likely to infect 12 to 16 others; in comparison, one person infected with the flu is expected to infect only one to two people.
Large measles outbreaks
The measles vaccine which is often combining with the mumps; and rubella vaccines and calling the MMR vaccine is highly effective; conveying 97% immunity after two doses. FRED is an “agent-based” modeling system, which means it creates a synthetic population using U.S. Census data and then assigns the synthetic people to move about their communities from home to work or school as people do in the real world.
This tool allows users to see, in silica, how a contagion could spread from person to person. In 2015, California legislators used FRED to help convince their peers to pass a bill restricting vaccine exemptions for school age children. Texas is the largest state by population that allows parents to opt their children out of required vaccines for religious or personal reasons. These exemptions have increased 28-fold in Texas, from 2,300 in 2013 to 64,000 in 2016.
Single case of measles
But in the FRED Measles Texas simulation, a single case of measles; is introducing into various metropolitan areas through a randomly selecting student whose parents have refusing to vaccinate. But the simulation runs for each city for 270 days the length of the typical school year at current vaccination rates and at a hypothetical decrease in those rates. At current rates, the simulation estimates that measles outbreaks of more than 400 cases; could occur in Austin and Dallas-Fort Worth.
Approximately 64% of the simulated cases occur in children who were unvaccinated because they had a religious or personal exemption. But the model forecasts 36% of the cases would be in people who have a medical condition that prohibited vaccination; whose vaccine failed to build immunity or in unvaccinated adults, for whom the risk of complications is higher than children.