Across the country, 626 individual cases of measles have been confirmed in 22 states — making this the second-greatest number of cases reported in the U.S. since measles were eliminated in 2000. Outbreaks can occur for a number of reasons, though the Centers for Disease Control and Prevention (CDC) point to two main reasons: increase in travelers who get measles abroad and bring it to the U.S., and the spread of measles in communities with pockets of unvaccinated people.

For public health professionals and infectious disease specialists, the outbreak has heightened their awareness to the prevalence of vaccine myths.

“I don’t think parents realize how rigorously studied vaccines are,” Dr. Nancy Messonnier, the acting director of the CDC's Center for Preparedness and Response, told TODAY. “We know vaccines are safe because we study them.”

Yet, she and others acknowledge that it’s easy to become confused with the overwhelming amount of information available.

“It is really important that people aren’t scared into getting the measles vaccine, but they are getting the information to restore their trust in the vaccination program,” she said. “We want everyone to feel good about vaccinating their children.”

Messonnier and other experts share some common myths they hear about vaccines and the facts behind them.

1. MYTH: VACCINES CAUSE AUTISM.

False: “This is a really important myth to get straight. Scientific studies and scientific reviews continue to show no relationship between vaccines and autism. Period,” Messonnier said.

Dr. Dan McGee a pediatric physician at Helen DeVos Children’s Hospital in Grand Rapids, Michigan, agreed.

“Vaccines do not cause autism,” he told TODAY. “There is absolutely no link.”

A recent Danish study confirmed what the experts reinforced. The study found that children who receive the measles, mumps and rubella (MMR) vaccine are 7% less likely to develop autism than their unvaccinated peers.

“This is considered a pretty definitive study,” Dr. Glenn Fennelly, an infectious disease specialist and professor of pediatrics at Rutgers New Jersey Medical School, told TODAY. “The measles, mumps and rubella vaccine doesn’t trigger autism.”

2. MYTH: MEASLES, CHICKENPOX, POLIO AND OTHER VACCINE-PREVENTABLE DISEASES ARE HARMLESS.

False: While many who develop chickenpox or measles will have only a mild illness, these diseases can still have deadly complications. People can develop encephalitis (inflammation of the brain), pneumonia or infections. Earlier this month, it was reported that a 43-year-old Israeli flight attendant with measles is in the intensive care unit because of complications.

“Some of them will get severely sick and some will be hospitalized and some of those children will die,” Messonnier said. “If you are the parent of that child … why risk it?”

3. MYTH: VACCINES CAUSE ILLNESS.

False: Some vaccines, such as the measles, mumps and rubella (MMR) vaccine, use a weakened form of the live virus to offer protection, what’s also known as an attenuated vaccine. But that doesn’t cause illness in people who get the shot, and it doesn't mean the person can pass it along.

“You can’t spread it,” McGee said.

Some experience a measles-like rash after receiving the MMR vaccine, but it doesn’t mean the person has measles.

“It is not contagious,” McGee explained. “You can get the rash but there is no fever or illness.”

A lot of people also believe the flu vaccine will give you the flu — it won't. It's biologically impossible for you to catch the flu from being vaccinated.

4. MYTH: PREGNANT WOMEN CAN’T GET VACCINATED.

Partially true: While doctors do not recommend that women get the MMR vaccine while pregnant, there are other vaccines they certainly should get, including the flu and whooping cough vaccines.

“There are some vaccines we recommend for pregnant women,” Messonnier explained. “Even for women who aren’t vaccinated and are pregnant you can get vaccinated as soon as possible (after delivery).”

Women who are unvaccinated and thinking of starting a family should consider getting their vaccinations first. Rubella, in particular, can “cause birth defects,” McGee said.

Also, it is safe for pregnant women to get the flu vaccine, the CDC said in January. An earlier study raised the possibility of early miscarriage from the flu shot, but the CDC report found no association between miscarriage and pregnant women who had received flu shots for three recent seasons. Pregnant women are especially vulnerable to flu symptoms.

5. MYTH: YOU DON’T HAVE TO STICK TO THE VACCINE SCHEDULE TO PROTECT YOUR CHILD.

False: The CDC publishes a vaccine schedule that provides a timeline when children should receive vaccines so they provide the most protections. Doctors normally give MMR, for example, at about 12 months, and a second dose when kids are about 4 to 6 years old. Delaying a dose makes children vulnerable.

“When you delay getting a vaccine you have unnecessary risk during the period of time that you could have been vaccinated,” Messonnier said.

McGee said that when people delay vaccines they’re more likely to forget to get all the needed shots.

“There is less compliance when you spread out the schedule,” he said.

6. MYTH: YOU DON’T NEED TO BE VACCINATED BECAUSE OTHER PEOPLE ARE.

False: People think that herd immunity can protect everyone who isn’t immunized. But Fennelly stresses that 90% of the population must be immunized for it to work. The U.S. government's target for MMR vaccination is 95%. Many of the recent measles outbreaks are happening in communities with low immunization rates, which means they're vulnerable.

“It’s pretty common one to come out. People say, ‘I don’t need to get my kid immunized because immunization rate is so high,’” Fennelly said.

7. MYTH: VACCINES OVERWHELM THE CHILD’S SYSTEM WITH TOO MANY ANTIGENS.

False: Sometimes children receive several vaccines at once, an experience that often ends in tears. It might seem as if all those antigens in the vaccines can overwhelm a baby’s immune system, but children can handle it.

“It does not overload the baby’s immune system,” Messonnier said. “I understand to a parent that it can be really traumatic."

McGee agreed and added that kids often encounter loads of germs.

“Any time your kid face plants into a carpet they are getting 1000 times more antigens,” he said.