With a surge in measles cases — including adults who thought they were protected by the vaccine — some are questioning whether they are properly vaccinated and whether they are still at risk for getting measles.
“I have never seen a case of measles,” he added. “But it’s just a matter of time.”
Adding to the uncertainty, some adults simply don’t know their vaccination status or have long lost their documentation, Cullen said. The history of the measles vaccine has also prompted questions about how people of different ages have been vaccinated: Not only has the recommended number of doses changed over the years, but so has the vaccine itself.
Several years ago, he recalled, a case of measles popped up in Fairbanks, Alaska — the state’s first case in years. Worried about having been exposed and uncertain about whether they were properly vaccinated, patients of his who had traveled there asked for a dose of the vaccine, just in case. (When given within three days of exposure to the virus, the vaccine may offer some protection or make the illness milder, according to health officials.)
Although Alaska hasn’t seen any cases this year, health officials issued an alert following a declaration of emergency in nearby Washington state, which has confirmed dozens of cases in 2019.
“If we see a substantial increase in the number of infections of measles, then there’s going to be a whole lot more people who are going to be wondering what their vaccine status is,” he said.
What are the current measles vaccine recommendations?
Doctors recommend two doses of the MMR vaccine, so called because it covers measles, mumps and rubella. Doctors give the first dose between 12 and 15 months, the second between 4 to 6 years.
The current recommendation was issued in 1989 by the US Centers for Disease Control and Prevention. Prior to that, a single-dose recommendation had been in place from 1963.
Before we had a vaccine, the agency says 3 million to 4 million Americans were infected yearly, including 48,000 hospitalizations and 400 to 500 deaths.
In some recent years, there have been fewer than 100 cases nationwide. But the virus has made a comeback in other years, including 2019 — largely due to anti-vaxers, experts say.
“The reason why we have vaccine hesitancy in this country is because people don’t remember how bad it was,” Cullen said.
One vs. two vaccine doses: What’s the difference?
If you were vaccinated with two doses, in line with the latest guidelines from 1989, the CDC says you have a 97% chance at being protected against measles. And if that last few percent happen to come into contact with the virus, they’re less likely to spread it to others, and their illness is often milder.
One dose is still about 93% effective at preventing the disease.
“Most virologists only dream of a solution as successful” as today’s measles vaccine, CDC’s principal deputy director, Dr. Anne Schuchat, wrote in 2015. “Success can breed complacency, skepticism or even attack,” she added.
The second dose, however, is not a booster per se. In research studies, nearly everyone developed signs of immunity to measles with a single dose — and the vast majority of the time, this immunity is lifelong, experts say.
