[Press Release, Jan 22, 2020 / unofficial translation ]



Key features and mechanism of action of COVID-19 vaccines [Press Release, Jan 22, 2020]



□ The Ministry of Food and Drug Safety (MFDS, Minister Kim Ganglip) provided the following clarification regarding the key features and mechanism of action of COVID-19 vaccines.


□ The mechanism of prevention against COVID-19 through vaccination:

1) A person becomes inoculated with a COVID-19 vaccine. --> 2) The antigens contained in the vaccine stimulate immune cells (B cells) --> 3) The stimulated B cells produce and store neutralizing antibodies that can destroy virus in the human body. --> 4) When COVID-19 virus enters the body through the respiratory tract, --> 5) the neutralizing antibodies remove the COVID-19 virus from the body.


□ A viral vector vaccine function by inserting genetic code for antigen into a non-pathogenic virus such as adenovirus so that the virus would produce antigen protein within a human body to trigger immune response. Some of the most prominent viral vector vaccines include those manufactured by AstraZeneca and Janssen (Johnson & Johnson). The two vaccines are expected to be distributed in Korea.

○ The AstraZeneca COVID-19 vaccine was authorized for emergency use in the U.K. on Dec. 30, 2020. Also, the European Medicines Agency (EMA) announced that it has been conducting a rolling review on the vaccine since October 2020.

- As AstraZeneca has applied for marketing authorization in Korea on Jan. 4, 2021, MFDS is currently conducting the concomitant review.

○ Janssen (Johnson & Johnson) has been conducting the phase III clinical trial of its COVID-19 vaccine since September 2020 and has not obtained any approval for the vaccines yet.
- In Korea, MFDS is currently conducting the rolling review of the non-clinical and quality data of the COVID-19 vaccine following Janssen’s request from Dec. 22, 2020.

○ As for the vaccines developed in Korea, phase I/II clinical trials of the Cellid COVID-19 vaccine are currently underway.


□ RNA vaccines induce immune response by injecting antigen genes in the form of RNAs for antigen production. Some of the most prominent RNA vaccines include those manufactured by Pfizer and Moderna. The two vaccines are expected to be distributed in Korea.

○ As of Jan. 7, 2020, the Pfizer COVID-19 vaccine received Emergency Use Authorization in the U.K. (Dec. 2, 2020), the U.S. (Dec. 11, 2020), and Canada (Dec. 9, 2020) and conditional marketing authorization in Switzerland (Dec. 19, 2020) and the E.U. (Dec. 21, 2020).

- Since the Pfizer vaccine has been used globally following WHO’s Emergency Use Listing of the Pfizer vaccine on Dec. 31, 2020, it is viewed as a promising product that can be applied universally.

- MFDS has initiated the rolling review of the non-clinical and clinical data on the vaccine upon Pfizer’s request submitted on Dec. 18, 2020.

○ As of Jan. 7, 2020, the Moderna COVID-19 vaccine was granted emergency use authorization in the U.S. (Dec. 18, 2020) and conditional marketing authorization in the E.U. (Jan. 6, 2021).

- Moderna has yet to apply for the rolling review and marketing authorization in Korea.

○ In Korea, Genexine and GeneOne Life Science are each developing a DNA vaccine in a form similar to that of RNA vaccines, and phase I/II clinical trials of the vaccines are underway.


□ Recombinant vaccines trigger immune response through the direct injection of antigen protein produced through genetic recombination technology and are one of the most commonly used vaccine platforms.

○ Novavax has begun the development of a recombinant vaccine against COVID-19 vaccine and has been conducting phase III clinical trial since September 2020. The vaccine is yet to receive any approval.

- In Korea, SK Bioscience is conducting phase I/II clinical trials of a recombinant vaccine.


□ Inactivated vaccines are a classic vaccine platform that trigger an immune response by injecting inactivated virus particles into the human body as antigens. Various types of inactivated vaccines have been developed.

○ Although inactivated vaccines can be swiftly developed and manufactured through simple procedures and induce the production of neutralizing antibodies successfully, a Biosafety Level 3* facility for the manufacture of inactivated vaccines against COVID-19 virus.

○ Inactivated vaccines against COVID-19 include those produced by China’s Sinopharm approved in China on Jul. 22, 2020.


□ According to the landscape of COVID-19 candidate vaccines published by WHO, a number of COVID-19 vaccines are under development. Some examples of such vaccines are manufactured by CanSino (viral vector vaccine) and the Gamaleya Research Institute in Russia (viral vector vaccine).


□ Mindful of the heightened public interest in the development of COVID-19 treatments and vaccines, MFDS will continue to provide updates on the safety and efficacy of vaccines and commit to creating a safe environment for vaccination.

○ MFDS will also thoroughly evaluate the safety and efficacy of COVID-19 candidate vaccines to ensure the distribution of safe COVID-19 vaccines in Korea.