Vaccination
A teenager receives tetanus vaccination at the Remote Area Medical and Operation Lone Star joint health clinic at Palmview High School in Mission, Texas, Aug. 5, 2014. Reuters

Traveling abroad for a holiday can be fun, but if you come back sick, or even worse, spread it around back at home, it won't be a happy story. Not getting the right vaccinations when you are going outside the country can be a source of trouble.

According to a recent study published in the journal “Annals of Internal Medicine,” more than half of international travelers from the U.S. between 2009 and 2014 who were eligible to receive the measles, mumps, rubella (MMR) vaccine before traveling did not get vaccinated.

Read: 2017 Immunization Guidelines Released After President's Skeptic Comments On Vaccinations

Authored by nine doctors, led by Dr. Emily Hyle, an instructor in medicine at Massachusetts General Hospital, the study is based on 40,810 adult travelers who visited one of 24 Global TravEpiNetclinic sites, affiliated with a hospital, medical school, doctor's office, pharmacy or public health clinic. The study was carried out to assess the measles immunity status of departing U.S. adult travelers who sought pretravel consultation.

The study found that of 40,810 travelers, 6,612 were eligible for MMR vaccine at the time of traveling abroad, but 3,477, or 53 percent, ended up not getting vaccinated. After analyzing a structured questionnaire completed by both travelers and providers during pretravel consultation, researchers found that 48 percent of travelers who were not vaccinated refused to get the vaccination, thinking it was unnecessary. Another 28 percent of the travelers did not get vaccination because the provider deemed the vaccine to be unnecessary and the remaining 24 percent could not get vaccinated due to health systems barriers.

According to Centers for Disease Control and Prevention, from Jan 1-April 22, 2017, 61 people from 10 states were reported to have measles and the majority of people who got measles were unvaccinated.

When going abroad for vacation, along with packing clothes and other accessories, getting vaccinated is also an integral part of preparation. And the vaccinations you need depend on where you are traveling to. For example, yellow fever vaccine is required when traveling to certain countries in Africa, Central America, or South America, according to the website of Department of Health & Human Services (HHS).

You should be up-to-date on routine vaccinations four to six weeks before traveling, so scheduling a prior appointment with your healthcare provider well in time. The gap between the day of the vaccination and the day you have to travel would give vaccines enough time to start working and if required, to get further doses.

The U.S. Centers for Disease Control and Prevention (CDC) divides travel vaccinations into three categories: routine, recommended and required.

Routine vaccinations, which are administered usually during childhood, are for diphtheria, tetanus, pertussis, measles, mumps, rubella, varicella, poliomyelitis, hepatitis B, hepatitis A, rotavirus, meningococcus, human papillomavirus, and pneumococcus.

Vaccinations for rabies, typhoid fever, and Japanese B encephalitis are recommended vaccines. Travelers should ensure that these vaccines are up-to-date since many conditions which are rare in the U.S. due to immunity in the general population may be more common in other countries.

Travelers to tropical countries are usually worried about the possibility of contracting malaria, which is an infection transmitted by the bite of a female Anopheles mosquito. Although malaria is prevalent in Africa, the disease occurs in over 100 countries, many of which are in other continents. Till now, there is no vaccination for it but doctors can prescribe preventive or prophylactic, anti-malarial medication if you are traveling to an at-risk area.

Common vaccinations for children before traveling are typhoid, yellow fever, Japanese B encephalitis, meningitis, and rabies.

All infants get the MMR vaccine at the age group of 12-15 months, but if you are planning to travel outside the country before your baby is that age, you can get your baby vaccinated as early as six months of age, according to the website KidsHealth.

"Pre-travel vaccinations are important because diseases that aren't found in the United States, such as typhoid or yellow fever, may be a risk in other countries. These diseases can be severe or even fatal," Dr. Phyllis Kozarsky, an expert travel health consultant with the CDC's Travelers' Health Branch and a professor at Emory University, told CNN.

"Even diseases that do occur in the United States, such as measles or hepatitis A, are often more common in other countries," she said. "Several countries in Europe are currently experiencing measles outbreaks, which emphasizes how important it is for travelers to be up-to-date on routine vaccines as well as get travel-related vaccines."

Read: WHO Declares Americas Have Been Declared Free Of Endemic Measles

Although measles was declared eliminated from the U.S. in 2000, according to CDC, it still remains common in many other parts of the world. For instance, there was an outbreak of measles in Italy, Germany, Belgium, Guinea, and Romania in 2017 itself.

According to Vaccination Knowledge Project of University of Oxford, England, measles causes death in at least 1 in 5000 cases in high income regions such as Western Europe.

“People often underestimate the risk of getting infections," Dr. Pritish Tosh, an infectious disease physician and researcher at the Mayo Clinic in Rochester, Minnesota, said, according to CNN. "The highest-risk group for travel-related illnesses tends to be people who think they are at a lower risk," he added.