[Issue Q&A] Vaccination for Children and Adolescents Aged 12-17 with the Same Dosage as Adults

Only with consent from teenagers and guardians
Two doses of Pfizer vaccine... UK administers one dose

Booster shot is Pfizer... Moderna to be added later
Janssen vaccination decision expected around December based on US cases

[Asia Economy Reporters Sojeong Seo, Chunhee Lee] COVID-19 vaccinations for children and adolescents aged 12 to 17 and pregnant women will begin on the 18th of next month. The interval between the first and second doses of messenger RNA (mRNA) vaccines such as Pfizer and Moderna will be shortened from the existing 6 weeks to 4-5 weeks, and booster shots for high-risk groups such as the elderly and medical personnel will also start from the 12th of next month.

Q. Is it safe for elementary school students to receive the vaccine?

A. Among 869,517 high school seniors (grade 3) vaccinated domestically, 26 reported adverse reactions such as myocarditis and pericarditis, and after review, only 15 cases were diagnosed as actual instances. By gender, 13 were male and 2 were female, showing a higher incidence in males. There were 10 mild cases and 5 severe cases, all of whom have now recovered and been discharged. No students died after vaccination. Based on the vaccination effect observed in Korean high school seniors, the infection prevention effect for those aged 16-18 is analyzed at 95.8%, and the prevention effect against severe illness and death is 100%.

Healthy children and adolescents without underlying conditions have a low risk from COVID-19, but vaccination is recommended because rare complications such as severe infection and multisystem inflammatory syndrome can occur. However, since vaccines are not perfect, there are also risks associated with vaccination. Vaccination is only carried out if the guardian (legal representative) consents on the consent form distributed through schools.

Q. Do children and adolescents receive the vaccine in the same dosage as adults?

A. Children and adolescents aged 12 to 17 receive two doses of the Pfizer vaccine at the same dosage as adults. The World Health Organization (WHO), the United States, Canada, Germany, and others all recommend the same dosage as adults. However, in the UK, only high-risk groups receive two doses, and children and adolescents receive only one dose. This is because the risk of progressing to severe illness in these age groups is low, and the benefits of vaccination are considered not to outweigh the risks of side effects such as myocarditis and pericarditis.

Choi Eun-hwa, Chair of the Vaccination Expert Committee, explained, "Although there are concerns about long-term safety, it is not desirable to completely exclude the option of vaccination due to such uncertainties, as vaccination provides COVID-19 prevention effects, contributes to quarantine efforts, and offers a choice to avoid negative impacts on mental health such as infringement of learning rights and psychological withdrawal."

Q. Which vaccines will be used for the booster shots?

On the 27th (local time), U.S. President Joe Biden received the Pfizer COVID-19 vaccine booster shot at the White House. [Image source=Reuters Yonhap News]

A. Booster shots will be administered using mRNA vaccines, either Pfizer or Moderna. However, for the currently announced booster shot recipients, Pfizer vaccine will be primarily used. Since the target groups initially received Pfizer or AstraZeneca vaccines, only the same vaccine or Pfizer vaccine, which has already been used in heterologous vaccination, was selected. Moderna vaccine will also be used for booster shots in the future.

Jung Eun-kyung, Head of the COVID-19 Vaccination Response Task Force (Director of the Korea Disease Control and Prevention Agency), stated, "Moderna vaccine will definitely be used for booster shots," but added, "The dosage and interval are still under review, so we will proceed after carefully examining overseas cases and clinical trial data from pharmaceutical companies."

Q. What is the basis for setting the booster shot recipients as those aged 60 and above?

A. Different countries apply various age criteria for booster shots depending on their situations. The United States and France set the elderly threshold at 65 years and older, Germany at 80 years and older, and the UK at 70 years and older, with plans to lower the booster shot age to adults aged 50 and above in the second phase. Singapore recently recommended booster shots for those aged 50 and above starting next month due to a surge in confirmed cases.

Our quarantine authorities explained, "Considering the rates of severe illness and fatality, we classified those aged 60 and above as high-risk groups in the first half of the year," and "Accordingly, the high-risk group age for booster shots after six months was set at 60 years and above."

Q. Can Janssen vaccine recipients also receive booster shots?

Janssen COVID-19 Vaccine [Image source=EPA Yonhap News]

A. Currently, the estimated breakthrough infection rate after vaccination in Korea is 40.2 cases per 100,000 people. By vaccine type, Janssen shows 161.2 cases, exceeding the average, while other vaccines are below average. Director Jung said, "Janssen has the clear limitation of being a single-dose vaccine," and added, "After review, we plan to announce additional vaccination plans in early December, six months after vaccination."

The type of vaccine for booster shots has not yet been decided. Germany and France have decided to administer mRNA vaccine boosters to Janssen recipients. However, the United States, which has the largest number of Janssen vaccine recipients, has currently postponed booster shots. Since recent studies show that two doses of Janssen vaccine provide 94% infection prevention and 100% prevention of severe illness, the US is likely to proceed with booster shots after two Janssen doses.

Q. If the first dose was AstraZeneca leftover vaccine, can the second dose be an mRNA vaccine?

A. For those aged 50 and above who received the AstraZeneca vaccine through leftover vaccine reservations, it is principle to receive the second dose with the same vaccine. Therefore, the second dose should also be AstraZeneca. However, the interval between the first and second AstraZeneca doses, previously 8 weeks, has been adjusted to 4-12 weeks, and reservation schedules can be changed starting from the 28th. If you want to complete vaccination sooner, you can bring forward the second dose schedule.