North Korean defectors living in South Korea have low levels of influenza vaccination due to poor health literacy, despite having fewer language barriers than other immigrants, a research paper showed.

The research team led by Park Sang-min, a professor of family medicine at Seoul National University Hospital, said on Wednesday that they published the study results on the latest issue of PLOS One, a scientific journal by the U.S. Public Library of Science (PLOS). National Cancer Center researcher Song In-gyu was the leading author.

The researchers surveyed the health literacy of 399 North Korean defectors from August to December in 2012 and analyzed the association between health literacy and influenza vaccination.

Out of 399 defectors, 116 (29.1 percent) had a flu vaccination.

Then, the team used the Shortened Form of Korean Health Literacy Scale (S-KHLS) to measure the health literacy of the people that will receive vaccinations. People whose S-KHLS scores were 9 or lower out of the full mark of 12 had only 19.7 percent influenza vaccination rate.

In contrary, those who scored 10 or more had more than 31 percent rate in flu vaccination

For North Korean defectors living alone with relatively low social support, health literacy had a more significant impact on their use of preventive health services such as influenza vaccination.

“This is the first study to assess the association between health literacy and use of preventive healthcare among North Korean defectors. With the prevention of a disease getting more important, we need to raise their health literacy through adequate interventions,” Song said.

Professor Park also said, “We should consider measures to improve their health literacy by learning from other countries’ health policies on immigrants.”