As measles cases continue to rise across the country, many adults are left wondering whether they are protected from the highly contagious virus.

Most people in the U.S. were vaccinated as children, particularly if they attended public schools.

But what about those who are unsure of their vaccination status? Is it safe to receive another vaccine if they were already vaccinated as a child?

"If you are in that situation where your vaccination status is unknown, you've lost your records or you don't remember or your parents can't remember, it is safe to proceed with what we call a booster shot," Dr. Jayne Morgan told Scripps News.

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Morgan emphasized how infectious measles is, explaining that for every person infected, health officials expect them to spread the virus to another 12 to 18 people.

"Often I get asked the question about is herd immunity, meaning what percentage of the population that really needs to be vaccinated such that everyone is protected and the virus cannot find a host in which to spread. And for measles, that number is really high — greater than 95% of the population. And we're sitting, right now, at about 92%."

According to the Centers for Disease Control and Prevention, there have been 222 reported cases of measles in the U.S. this year as of March 6. A third of those cases involved children under the age of five.

So far, two deaths have been linked to measles this year, both in individuals who were unvaccinated.

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