Measles outbreak: Do adults need a booster?

June 6, 2019

CDC has issued a statement to put to rest the question of whether adults need a booster for measles protection

The mainstream media is jumping on the measles booster bandwagon, teasing the public with headlines about needing additional measles vaccines.

While there are some specific cases in which additional measles vaccination may be required, the CDC has cemented its stance on measles vaccination in an interim update that has been sent to clinicians across the county.

In the guidance, released by CDC in May, the agency confirms that recommendations for vaccination and assessing immunity adults has not changed since the Advisory Committee on Immunization Practices (ACIP) last published guidance on the Prevention of Measles, Rubella, Congenital Rubella syndrome, and Mumps in June 2013.

Recognizing, however, that the current outbreak is raising fears among the public and that clinicians may want some updated-or at least confirmed-guidance, CDC issued the interim guidance confirming that most adults in the U.S. are at low-risk of contracting the disease.

Windel A. Stracener, MD, FAAFP, a family physician in Richmond, Ind., and a member of the American Academy of Family Physicians’ Board of Directors, said the interim guidance may serve as a gentle reminder for clinicians that may find themselves in the midst of an outbreak and haven’t seen a case of measles in a while, if ever.

“I haven’t seen a case of measles in several years. It’s one of those things you learn about, but if you don’t see it often, it doesn’t come to the front of your mind,” Stracener said. “If you’re in an outbreak area, these letters, from my perspective as a clinician, are helpful reminders about symptoms and diagnostic characteristics.”

The letter from CDC highlights the fact that providers do not need to actively screen adult patients for measles immunity, but should check with their local health departments on any more up-to-date recommendations during an outbreak.

Additionally, providers should make sure that patients who are traveling internationally be protected, vaccinating them rather than testing for immunity if their current immunity status is uncertain.

While measles outbreaks have captured the attention of the country in recent years, the annual incidence of measles in adults was less than 0.5 per 1 million individuals, according to CDC’s guidance. Immunity for individuals in the 20- to 49-year-old range is 87.9 percent to 93.3 percent, according to CDC, suggesting high immunity in the adult population. Of the 839 cases of measles that were reported so far this year, CDC notes that just 26 percent were adult cases, and 65 percent of those adult cases were associated with outbreaks in under-immunized communities.

Some adults still are designated at high risk for acquiring or transmitting measles, according to CDC, and these include college students, healthcare personnel, and international travelers. However, re-vaccination is not necessary when high-risk individuals have written documentation of two doses of the MMR vaccine or presumptive evidence of immunity, which includes birth before 1957, laboratory evidence of immunity, or laboratory confirmation of disease.

An exception is with healthcare workers, who should be vaccinated with two doses of the vaccine if they lack laboratory confirmation of immunity or disease and were born before 1957, according to CDC. Local health departments may also have changes to the recommendation during specific outbreaks based on the location and epidemiology of the outbreak, the agency notes.

For most adults, however, CDC confirms that one dose of the MMR vaccine is sufficient, and there really are no circumstances that would warrant a third dose of the vaccine. A small population of adults who were born between 1963 to 1967 that received a killed version of the measles vaccine should be vaccinated with a second dose of the MMR vaccine, CDC notes, and those with unknown immunity status should be vaccinated with a single dose of the MMR vaccine, as well.