Children in the United States get immunized for more than 12 childhood diseases, and it is a prerequisite for being able to attend school. Up until recently, the rates of childhood illness was at the lowest in years.

Outbreaks of measles — concentrated primarily in Ohio and California — in recent months indicate that there is still need for vigilance in protecting against infectious diseases. At least 18 states have reported particularly high rates of measles in recent weeks.

In the first quarter of 2014, 60 cases of measles have been reported in California, and this is the highest rate since 1995. Ohio reported 138 cases, with at least seven requiring hospitalization. In California and Ohio, the infected were among travelers to the Philippines, where 32,000 have come down with measles, and the epidemic has resulted at least 41 deaths. The majority of those infected in Ohio came from members of the Amish community, and many had traveled to the Philippines recently.

The total numbers of cases reported is up to 288, with Ohio having the highest number, followed by California and then New York at 26. It is estimated that 85 percent of the cases reported this year were in people not receiving vaccinations due to religious, philosophical or personal objections.

The Centers for Disease Control and Prevention (CDC) is reporting a wide range of ages in the epidemic — with two months at the youngest, and the oldest reported case impacting a 65-year-old. But the cases in the most recent outbreak of measles are primarily among adults, with over one half of the disease occurring in those over the age of 20.

Complicating the identification and treatment of these cases is the lack of recognition by clinical providers.

"Because of the success of the measles vaccine, many clinicians have never seen measles and may not be able to recognize its features," Dr. Julia Sammons reports in a recent publication in the Annals of Internal Medicine.

Immunization is considered key in preventing the spread of several diseases, including measles. Measles is considered to be one of the most contagious of infectious diseases. Symptoms include fever, cough, conjunctivitis and rash; in rare cases it leads to pneumonia and brain inflammation.

Prior to the most recent outbreak, the last reported death in the United States was in 2005. Vaccinations are attributed to having prevented 323 million illnesses and 732,000 deaths. According to the CDC, it is critical to maintain high rates of immunization, particularly with the measles-mumps-rubella (MMR) vaccine.

"We recommend two doses of MMR for full protection," said Anne Schuchat, the director of the CDC's National Center for Immunization and Respiratory Diseases. "The usual timing is for babies to get it at 12 to 15 months, and a second dose at 4 to 6 years of age. But for babies under 12 months who are traveling or in an outbreak, we recommend starting at 6 months."

Groups who are traveling or were born before the measles vaccine in 1963 are the most at risk for infections due to lack of immunizations, but they are not the only ones.

A 2012 study published in the Journal of Immigration and Minority Health found that even when controlling for socioeconomic status, children having a foreign-born mother were at least 14 percent more likely to have not completed the recommended immunization series. Children of noncitizen mothers who had resided for less than five years in the United States were also more likely to have failed to complete the recommended immunization dosing.

While reasons for not obtaining vaccinations for children is complex; some reasons provided by families include: "My baby cries when she gets the shot" and "My child is too young to get so many vaccines."

The need for increased awareness about immunizations and symptoms of measles is evident. A higher level of vigilance among clinicians and increased education for groups at risk will help prevent the spread of a disease that was once on the way to eradication.