A measles outbreak in New York has been called the largest in the state's recent history, and it's occurring at a time when there have been spikes in measles cases globally. Since the outbreak emerged in September, measles has been diagnosed in at least 112 people across Rockland and Orange counties and at least 55 in New York City, CNN reports.

Measles is a highly contagious disease that is transmitted by sneezing and coughing, as well as direct contact with an infected person. Symptoms include fever and rash, usually lasting several days. Infected people are contagious from four days before through four days after the rash appears.

Rates of unvaccinated and exempted children on the rise, says CDC

The CDC recommends that people get the measles, mumps and rubella vaccine, or MMR, to protect against those viruses. The typical recommendations are that children should get two doses of MMR vaccine. Recently, there has been a rise in unvaccinated children.

A CDC report said that the proportion of children receiving no vaccine doses by 2 years old rose from 0.9% among those born in 2011 to 1.3% among those born in 2015. The Health Department continues to strongly recommend unvaccinated individuals to get vaccinated now, especially before traveling internationally.

Many of our cases were travel-associated

Nationally, 2018 saw the second-highest number of measles diagnoses in more than two decades, with 273 cases. "Many of our cases were travel-associated," Dr. Jane Zucker said.

"So unvaccinated children had acquired their infection overseas. There are large outbreaks in many countries in Europe, as well as a very large outbreak in Israel, and so people need to be protected before they travel," she said.

Measles cases surged globally in 2017 due to gaps in vaccine coverage, health agencies say. When a large percentage of the population is vaccinated, "herd immunity" will protect against the spread of disease among the unvaccinated or partially vaccinated, including babies.

Overwhelming and scary

Unvaccinated travelers can quickly share the illness when they arrive in the United States, especially if they are part of a community that has low vaccination. There are ongoing outbreaks of measles in Israel, Ukraine, Italy, Moldova and Colombia, among several other countries.

"I would say this is the largest measles outbreak that New York state has had in recent history," said Dr. Howard Zucker, the state commissioner of health.

Why not make measles vaccines mandatory? 

To address the outbreak in New York, Dr. Zucker said Tuesday that many outreach efforts to communities have been made to encourage getting vaccinated and minimizing the risk when any student is not vaccinated. In the state of New York, measles immunization is required of children enrolled in schools, day cares and pre-kindergarten.

Diseases like measles can travel very quickly across the country. It just takes one person on an airplane to infect 90% of unvaccinated people on that airplane and fly to any other state around the country. So the take-home message is to make sure your children are up-to-date on vaccines.