[Q&A] '5th Dose' Not 'Winter Vaccination'... What Changes?

[Image source=Yonhap News]

[Asia Economy Reporter Kim Young-won] The government has announced a new vaccination plan direction for the upcoming winter season. One notable point is that, unlike before, the term 'nth dose vaccination' was replaced with the name '2022~2023 Winter COVID-19 Vaccination Plan.' For the first time, updated vaccines targeting variants such as BA.1, BA.4, and BA.5 are expected to be used in this vaccination campaign.

Why was the name changed from the 5th dose vaccination to the ‘Winter Vaccination Plan’?

Until now, vaccinations were centered around dose counts, but the government explained that the name reflects a plan to shift to season-based vaccinations similar to influenza (flu). Another reason for establishing the vaccination plan based on timing rather than dose count is the emergence of new vaccines targeting variants. Lim Eum-gi, head of the COVID-19 Vaccination Response Task Force’s Vaccination Management Division, explained, "Influenza has seasonality, and although COVID-19 does not yet have such regularity, it cannot be said to be the same as influenza, but we see this as a transitional phase moving toward regular vaccinations like influenza, hence the naming."

What updated vaccines will be used in this vaccination? When will they be introduced?

Updated bivalent vaccines targeting Omicron BA.1, BA.4, and BA.5 will be used. Currently, Moderna’s BA.1-targeting vaccine (Moderna Spikevax 2 doses) is the furthest along in domestic approval procedures, so vaccinations are expected to be possible in the fourth quarter of this year. Pfizer’s BA.1-targeting vaccine (Comirnaty 2 doses 0.1 mg/mL) also applied for product approval with the Ministry of Food and Drug Safety on the 29th of last month. Authorities stated that depending on the progress of product approval, BA.4 and BA.5-targeting vaccines will also be rapidly introduced.

What updated vaccines have been developed so far?

So far, a total of four updated vaccines are under development and approval worldwide. Pfizer and Moderna’s BA.1-based vaccines have applied for domestic product approval, and among them, Moderna’s vaccine has been approved for use in the United Kingdom. Regarding BA.4 and BA.5-targeting vaccines, Pfizer and Moderna applied for emergency use authorization in the United States on the 22nd and 23rd of last month, respectively. On the 31st of last month (local time), the U.S. Food and Drug Administration (FDA) granted emergency use authorization for Pfizer and Moderna’s BA.4/BA.5-targeting vaccines. Pfizer’s vaccine is for those aged 12 and older, and Moderna’s is for those aged 18 and older.

What is the efficacy of the updated vaccines?

According to clinical data, Moderna’s BA.1-targeting vaccine showed 1.69 times higher neutralizing ability against BA.4 and BA.5 compared to existing vaccines. Pfizer’s BA.4/BA.5-targeting vaccine showed a 2.6-fold increase in neutralizing ability against these variants compared to existing vaccines in preclinical results. However, BA.4/BA.5-targeting vaccines currently only have preclinical results conducted on animals, not humans.

Who are the vaccination targets?

The vaccination targets for this winter season are adults aged 18 and older, with priority given to vulnerable groups. Priority group 1 includes seniors aged 60 and above, immunocompromised individuals, and residents of nursing hospitals and facilities. Priority group 2 includes people in their 50s, those with underlying conditions, and healthcare workers. Vaccination is recommended for priority groups 1 and 2, while adults aged 18 to 49 (priority group 3) are not recommended. Updated vaccines will only be used for additional doses (3rd dose or higher).

What is the interval between vaccinations? Are there any health concerns about frequent vaccinations?

The vaccination interval is expected to be 4 to 6 months after the initial vaccination date or confirmation date of infection. This interval is also recommended by the World Health Organization (WHO). Regarding concerns about frequent vaccinations, health authorities responded that there were no significant adverse reactions when variant vaccines were administered to those who had received the 3rd or 4th doses. Baek Kyung-ran, Commissioner of the Korea Disease Control and Prevention Agency, explained, "We recommend a minimum vaccination interval of about 4 to 6 months, and the WHO also considers that such an interval would not pose significant problems. We understand that similar evaluations are being made in other countries as well."

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