Updating the standard childhood immunization strategy… HPV from age 11

In 2023, the standard vaccination strategy for children and young people was updated. The human papillomavirus (HPV) vaccine was changed from age 12 to 11, and the interval between vaccinations for the Japanese encephalitis vaccine also changed.

On the 24th, the Korean Vaccine Association held the 21st Spring Conference at L Convention and shared the revised standard vaccination cycle for children and young people in 2023 and its rationale.

Human papillomavirus is transmitted through the 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% falls into a state of ‘persistent infection’. In this case, it develops into cancer after years or decades.

As of 2019, the first and second doses of HPV were at age 12. On the other hand, this revised version changed to receive the first and second vaccinations at 11 to 12 years of age.

Lee Hyun-joo, professor of pediatrics at Seoul National University Bundang Hospital who published a review of standard vaccination, said, “It has been estimated that 79% of cancers caused by human papillomavirus in the United States account for.” he said.

“HPV infection is transmitted through sexual contact, so vaccination before sexual experience shows the optimal effect,” he said.

“When vaccinated at the age of 9 to 15, the immune response is higher than the response for older people,” he said. It is cost-effective to vaccinate twice,” explained the background of the guideline change.

The results of the Swedish registry survey 2020 also support this. As a result of the study, the risk of cervical cancer was reduced by 88% among those under 17 who were vaccinated compared to unvaccinated people, while the risk was reduced by only 53% in those who were vaccination 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, with the interval between 2 doses set at 0.6 months. This is to ensure that vaccination is completed prior to the experience.”

He said, “The minimum vaccination interval standard from 2015 to 2018 was vaccination at least 5 months after the first vaccination for Cervarix and Gardasil 9, and at least 6 months for Gardasil after vaccination,” he said. Aged 15, the second vaccination was given every 5 months or more and it stopped.”

The vaccination method for the Tdap (adult tetanus, diphtheria, pertussis) vaccine has also changed.

The current vaccination method was to inoculate 0.5 mL of Td twice every 4-8 weeks if DTaP was not vaccinated before 7 years of age, and the 3rd vaccination was given 6-12 months after the 2nd vaccination.

The revised guideline recommends that if DTaP is not administered before age 7, Tdap or Td should be given twice at least 4 weeks apart, and the third dose should be given 6 to 12 months after the second dose. However, at least one dose of Tdap is given, and in this case, the first dose is recommended.

In the case of Japanese encephalitis vaccine, in the case of an inactive 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 period was shortened from 12 months to 11 months.

The vaccination schedule for live vaccines is to give the first vaccination 12 to 23 months and the second vaccination 12 months later. The minimum interval between the 1st and 2nd vaccine is 4 weeks.

Professor Lee said, “There were studies in 2016 and 2020 that evaluated the safety and immunogenicity of cross-vaccinating inactivated and live vaccines. Vaccination is possible, but cross-vaccination between inactivated and live vaccines is not recommended.”