The United States is seeing the highest level of measles infections in more than two decades, and California has seen 45 cases this year.
Meanwhile, some lawmakers are pushing to make it harder for parents to get exemptions from vaccinations.
The proposals and the outbreaks have prompted confusion, and a lot of questions. CapRadio’s health care reporter Sammy Caiola answered queries from listeners, and from the CapRadio staff.
Q: Why are measles outbreaks happening?
Experts say most of the recent cases originated with adults who are unvaccinated or undervaccinated bringing the disease back from countries where it’s common. Measles tends to spike in winter, and the case numbers should level out as the temperature warms.
Q: What countries are the measles cases being imported from?
There have been four California outbreaks so far, all linked to international travel. Of the 45 cases in the state, at least 30 are tied to these outbreaks and the rest are stand-alone cases, according to the latest data from the California Department of Public Health. International travelers visited the Philippines, Thailand, India, Ukraine, Vietnam and Cambodia.
Q: Are any of the cases occurring in patients who have been vaccinated for measles?
According to the department, more than three-quarters of the individuals who have come down with measles in California were unvaccinated or undervaccinated, meaning they’d only had one dose of the measles shot.
Dr. Gil Chavez, deputy director of the state’s Center for Infectious Diseases, said some people who contracted measles had two full doses of the vaccination, which is 97% effective.
“What that means is that even in the best of cases, 3% of people who are immunized are not fully protected,” he said. “And when you multiply 3% by 30 million people in California, that’s a lot of people that potentially could be susceptible to measles even if they were vaccinated.”
The health department is urging anyone who has international travel plans to make sure their shots are up-to-date before they go.
Q: How long does the measles vaccine remain effective? Do adults need booster shots to maintain immunity?
It depends on when you were born. According to the U.S. Centers for Disease Control and Prevention, people who received two doses of the measles vaccination as children – which includes most people born after 1989 – are protected for life and do not need a booster dose.
If you were born between 1957 and 1988, you might have gotten an older, single-dose version of the measles vaccine that is less effective, but still officials are not recommending revaccination for this group unless you’re traveling internationally or work in health care. People who were born between 1963 and 1967 may have received an alternative version of the vaccine that was not effective, so health officials are recommending those people get re-vaccinated.
If you were born before 1957 you most likely caught measles as a child and therefore have natural immunity. Officials are not recommending vaccination for this group unless people are traveling internationally or work in healthcare.
The best way to find out whether your shots are up-to-date is to call your physician.
Q: If the cases are being brought in from unvaccinated adults traveling to countries where measles is common, then why are we talking about school-age children not getting their shots?
There’s always a risk that unvaccinated travelers will bring measles back from abroad. But when diseases are brought back to communities where most people are vaccinated, they’re unlikely to spread and instead remain stand-alone cases. The outbreaks occur when someone brings measles back to an area with low vaccination rates, because kids are especially good at spreading germs.
Dr. Karen Smith, director of the California Department of Public Health, said the goal is twofold — making sure traveling adults are vaccinated, and keeping vaccination levels high among children. She said SB 277, the 2016 law that eliminated personal belief exemptions in school, has helped with the second issue.
“We saw an almost 5 percent increase in vaccinations across the state of California,” she said. “That demonstrates just how valuable school requirements for vaccination are to ensuring that we have good community resistance to measles as it’s imported into California.”
Only children with medical exemptions can enter school without the required vaccinations. There has been some concern that parents are getting falsified medical exemptions, so SB 276 would give the state health department, rather than physicians, the final say on those forms.
Medical exemption rates have spiked since the state banned personal belief exemptions. The California Department of Public Health recently launched a review of schools where the medical exemption rate — sometimes as high as 50% — is much higher than the number of children likely to have medical conditions that prevent them from getting their shots (see next question for more information).
Q: What are the medical reasons for postponing vaccinations or not vaccinating some children?
People with severe, life-threatening allergies may be advised not to get certain shots. If someone has a weakened immune system due to diseases such as cancer or HIV/AIDS, or from treatments including radiation and chemotherapy, they can’t get vaccinated. There are a number of other restrictions, which can be found here. Patients should tell their vaccine provider if they have tuberculosis, if they’ve recently had a blood transfusion, or if they have a close family member with a history of immune system problems.
Q: Is it true that children under 12 months old can’t be vaccinated for measles? How should parents of infants that age protect their kids?
Children age six months to 12 months can be vaccinated for measles, but doctors don’t recommend it unless families are traveling internationally or the child is in a community where their risk for measles is high.
Children are naturally protected by their mothers’ antibodies for at least the first six months of life, which makes the vaccine less effective. So infants who get their shots before their first birthday should get two more doses per the regular schedule —– one shortly after the one-year mark, and one when they’re between 4 and 6 years old.
“Mothers typically have been vaccinated, so they will passively transfer those protective antibodies to the baby through the placenta prior to birth, and that will protect the child in the first few months of life,” said Dr. Paul Offit, director of the Vaccine Education Center at the Children’s Hospital of Philadelphia.
Generally, the first dose of the measles, mumps and rubella vaccine is given to children between 12 and 15 months of age. The CDC is recommending that infants age six to 11 months old who are traveling internationally get vaccinated.
If an infant is over six months of age, parents who are worried about potential measles exposure can speak with their physicians about vaccinating early.
Q: What is a vaccine injury, and how often does it happen?
Serious side effects from vaccines are rare.
Patients who believe they’ve been harmed by vaccines can file a petition with the federal Vaccine Injury Compensation Program. According to the CDC, 3,737 petitions were compensated between 2006 and 2016. More than 3.1 billion doses of covered vaccines were distributed during that time, which means that for every 1 million doses of vaccine that were distributed, one1 individual was compensated.
The center does keep a database where doctors, nurses, vaccine manufacturers, or members of the public can report adverse effects after a vaccination. Approximately 30,000 reports are filed each year, and roughly 90 percent describe mild side effects. But just because someone reports an injury after getting a shot does not mean that injury was caused by the vaccination.
According to the CDC, minor reactions to the measles, mumps and rubella vaccine include fevers, rashes, swollen glands, and soreness at the injection site. Moderate events include seizures, joint stiffness, unusual bleeding or bruising and full-body rashes. More serious, rare events include deafness, long-term seizures and brain damage.
There is no scientific evidence showing that vaccines cause autism, and the vaccine court has never compensated a petitioner claiming that a vaccine caused autism.
Q: When is a quarantine necessary?
People with confirmed cases of measles are put in isolation for four days after they develop a rash. Those who have potentially been exposed, such as unvaccinated students attending a school where there’s been at least one confirmed case, are typically quarantined for three weeks at the discretion of their local health department. This can help contain disease, especially in areas where there are high numbers of unvaccinated people.
Correction: A previous version of this story misstated the way public health officials handle people infected with measles. Those people should be isolated for four days after a rash develops.