Getting vaccinated can help stop measles from spreading
Most of the measles cases during the recent historic outbreak have occurred in children, but adults in high risk environments – like UCLA or California State University, Los Angeles, where people were exposed to the virus – may need to get another dose of the vaccine, according to the the Centers for Disease Control and Prevention.
Adults born before 1957, when the vaccine was introduced, are assumed to have immunity from the disease. But adults born between 1957 and 1989 may have received only one, potentially weaker, dose or no doses.
“Most adults are protected against measles, that’s what the science says,” Dr. Nancy Messonnier, the director of the National Center for Immunization and Respiratory Diseases, said in a teleconference April 29, “including people who were born before the measles vaccine was recommended and even people who only got a single dose of measles.”
When the vaccine first came out, there were two versions. One was much less effective than the other. That, combined with the fact that most older adults don’t have access to their childhood medical records, makes the immunity status of some adults unclear.
Giving children two doses of the vaccine became routine in 1989. One dose of the current iteration provides 93 percent immunity, according to CDC, and a second shot raises the level to 97 percent.
The CDC recommends children get the measles vaccine once between the ages of 12 and 15 months and again between the ages of 4 and 6.
Messonier said the CDC is focusing adult vaccination efforts on those who are traveling internationally; who work in environments such as health care, which may bring them in contact with the virus; or who live in the communities where outbreaks have occurred.
Based on this recommendation, adults who live near or work for UCLA or Cal State Los Angeles, which last week initiated quarantines after contagious people were on campus, may need another dose of the vaccine.
The three confirmed measles cases in Sacramento County were all within one family that had traveled internationally, according to the Sacramento County Public Health Department. One of the three was an adult. The two children were not vaccinated.
The latest measles case in Los Angeles County involves someone who arrived April 23 at Los Angeles International Airport, the county Department of Public Health said Tuesday.
“Health care workers are held to a higher standard,” said Dr. Dean Blumberg, chief of pediatric infectious diseases at UC Davis Children’s Hospital. “They could potentially expose patients.”
Blumberg said this means all health care workers must either present records of their immunizations or a physician’s diagnoses of childhood measles, or get a blood test to check their immunity status before they can begin working at the hospital.
“Blood tests are generally accurate and easy to get,” Blumberg said. “It’s a standard blood test.”
Immunity in vaccinated adults has not waned over time, Messonier said, though CDC will continue to monitor the safety and effectiveness of the vaccine.