In 2023, the standard vaccination strategy for children and adolescents was updated. The human papillomavirus vaccine (HPV) was changed from the age of 12 to 11, and the interval between vaccinations for the Japanese encephalitis vaccine also changed.
On the 24th, the Korean Vaccine Society held the 21st Spring Conference at L Convention and shared the standard vaccination cycle for children and adolescents revised in 2023 and its rationale.
Human papillomavirus is transmitted through skin, mucous membranes, and genital infections. It is transmitted mainly through sexual contact and disappears naturally within 12 to 24 months, but 3 to 10% fall into a ‘persistent infection’ state. In this case, it develops into cancer after years or decades.
As of 2019, the first and second doses of HPV were 12 years old. On the other hand, this revised version changed to receiving the first and second vaccinations at the age of 11 to 12 years.
Lee Hyun-joo, a professor of pediatrics at Seoul National University Bundang Hospital who announced the revision of standard vaccination, said, “It has been estimated that 79% of cancers caused by human papillomavirus in the United States are accounted for.” said.
“HPV infection is transmitted through sexual contact, so vaccination before sexual experience shows the optimal effect,” he said. “he explained.
“When vaccinated at the age of 9 to 15 years, the immune response is higher than that at older ages,” he said. It is cost-effective to inoculate twice,” he explained the background of the guideline change.
The results of the 2020 Swedish registry survey also support this. As a result of the study, the risk of cervical cancer was reduced by 88% in vaccinated persons under the age of 17 compared to unvaccinated persons, whereas the risk decreased only by 53% in those vaccinated between the ages of 17 and 39.
Professor Lee said, “The WHO SAGE guideline allows 2 doses of vaccination for those vaccinated before the age of 15, and the interval between 2 doses is set at 0.6 months. This is to ensure that the vaccination is completed before the experience.”
He said, “The minimum vaccination interval standard from 2015 to 2018 was to inoculate at least 5 months after the first vaccination for Cervarix and Gardasil 9, and at least 6 months for Gardasil after vaccination,” he said. If the vaccination was received under the age of 15, the second vaccination was given at intervals of 5 months or more and ended.”
The vaccination method for Tdap (tetanus, diphtheria, adult pertussis) vaccine has also changed.
The existing inoculation method was to inoculate 0.5 mL of Td twice at 4-8 week intervals if DTaP was not vaccinated before the age of 7, and the 3rd inoculation was given 6-12 months after the 2nd inoculation.
The revised guideline recommends that if DTaP is not administered before the age of 7, Tdap or Td should be given twice at least 4 weeks apart, and the third dose should be administered 6 to 12 months after the second dose. However, at least one dose of Tdap is administered, and in this case, the first dose is recommended.
In the case of Japanese encephalitis vaccine, in the case of inactivated vaccine, the interval between the next vaccination after the first vaccination was changed from 7 to 30 days to 1 month, and the minimum interval between the next vaccination was changed from 7 days to 4 weeks. After the second vaccination, the next vaccination interval was shortened from 12 months to 11 months.
The vaccination schedule for live vaccines is to administer the first vaccination at 12 to 23 months and the second vaccination 12 months later. The minimum interval between the 1st and 2nd vaccination is 4 weeks.
Professor Lee said, “There were studies in 2016 and 2020 that evaluated the safety and immunogenicity of cross-vaccination of inactivated and live vaccines. Vaccination is possible, but cross-vaccination between inactivated and live vaccines is not recommended.”
