[Issue Q&A] Pfizer Vaccine Can Be Administered to 7 People, But No Mandatory Vaccination Plan

Extra Vaccine Volume Included to Compensate for Drug Loss
Sufficient Extra Volume Allows Additional Vaccinations

No Drug Loss with LDS Syringes, 6 Doses Easily Possible

Pfizer Vaccine + Saline Not a 'Water Vaccine'... Official Usage
7 Doses per Vial, Not the 'World's First'... First at Officialization

On the morning of the 27th of last month, when Pfizer vaccine administration began for medical staff treating COVID-19 patients, medical personnel were preparing doses of the Pfizer vaccine in syringes at a sterile workstation (clean bench) inside the Central Vaccination Center of the National Medical Center in Jung-gu, Seoul. Photo by Joint Press Corps

[Asia Economy Reporter Lee Chun-hee] Although COVID-19 vaccinations have begun, an unexpected controversy over additional vaccine doses has emerged. There is an opinion that by using the latest domestically produced syringes, the number of doses per vial of Pfizer vaccine, which can normally vaccinate 6 people, can be increased to 7. Amid claims of this being a 'world first,' online rumors have also surfaced alleging that 'water vaccines' were made by diluting the vaccine due to shortages.

Q. How is additional vaccination possible?

A. Vials contain extra volume to compensate for drug loss during administration. Each Pfizer vaccine vial contains 0.45 mL of vaccine, which is diluted with 1.8 mL of normal saline to produce a total of 2.25 mL of diluted vaccine. If the full 0.3 mL dose per injection is administered without any loss, up to 7.5 doses can be drawn.

The Vaccination Promotion Team also issued a notice nationwide on the 27th of last month stating that additional doses can be given if residual amounts remain. However, as concerns about plan stability and contamination arose, Director Jeong Eun-kyung of the Korea Disease Control and Prevention Agency (KDCA) emphasized on the 1st that "the vaccination dose must be strictly followed, and mixing multiple vials must never occur," and that there is no plan to mandate 7 doses per vial.

Q. What is a 'Low Dead Space (LDS) syringe'?

A. LDS syringes are essential for smooth COVID-19 vaccination. Conventional syringes have a 'dead space' between the piston tip and the needle, leaving up to 0.07 mL of vaccine unused. LDS syringes minimize this dead space, reducing leftover vaccine to about 0.035 mL.

With standard syringes, approximately 0.37 mL must be drawn per dose, making it difficult to achieve 6 doses if any loss occurs during administration. However, using LDS syringes makes 6 doses per vial easily achievable.

Japan, which introduced the Pfizer vaccine earlier than Korea, failed to procure LDS syringes and thus reduced the number of doses per vial to 5. Consequently, the number of people eligible for vaccination decreased from 72 million to 60 million.

Q. Did they make 'water vaccines' by adding normal saline?

A. This is the official method.

According to the vaccination guidelines distributed by the government, the Pfizer vaccine is diluted by injecting 1.8 mL of normal saline into the vial before use. Then, 0.3 mL doses are extracted from the diluted vaccine for administration.

Official guidelines from Pfizer, as well as dosing instructions from the U.S. Centers for Disease Control and Prevention (CDC), the Food and Drug Administration (FDA), and Public Health England (PHE), all specify the use of diluted vaccine with normal saline. However, AstraZeneca, Moderna, and Janssen vaccines are administered undiluted.

Q. How is this handled overseas?

A. Although the National Medical Center emphasized this as a world first, strictly speaking, it is not. The FDA recommended in December last year that up to 7 doses per vial could be administered depending on circumstances, and Canada has also successfully administered 7 doses per vial.

However, there is no official standard yet for 7 doses per vial. The U.S. ultimately set 6 doses per vial as the official standard. Since the KDCA plans to discuss this with the Ministry of Food and Drug Safety, if 7 doses per vial are officially approved, it would indeed be a world first.

This content was produced with the assistance of AI translation services.