Vaccine Evasion Fear 'XBB.1.5 Variant' Still, Vaccination Is the Only Way...

High Immune Evasion but Vaccination Needed to Prevent Severe Cases
Why Health Authorities Recommend Bivalent Vaccine Administration

[Asia Economy Reporter Hyunju Park] "Existing vaccines do not work," "Vaccine neutralization".... Terrifying analyses about the COVID-19 XBB.1.5 variant, which is rampant in the United States, are pouring in. Citizens are deeply concerned about whether they should get the updated vaccine in preparation for the new variant that has strong immune evasion capabilities enough to neutralize existing vaccines.

XBB.1.5 is known to have the strongest transmissibility and immune evasion among existing variant viruses. It is said to surpass the XBB variant, which was called the "worst existing COVID-19 variant." XBB.1.5 is a subvariant of XBB derived from Stealth Omicron (BA.2), and compared to previously discovered variants, it has many mutations in the spike protein, resulting in high immune evasion. Since vaccines are developed based on the characteristics of the spike protein, the more mutations there are, the less effective the vaccine inevitably becomes.

Dr. Anthony Fauci, the former head of the U.S. COVID-19 response, also expressed concern in a briefing last November, stating, "XBB subvariants reduce the immune effect provided by booster shots," and added, "While vaccine effectiveness can be expected, it does not provide complete protection."

As a result, citizens are questioning the necessity of vaccination. With the prolonged COVID-19 situation causing vaccination fatigue and warnings about the immune evasion of the new variant, trust in vaccine effectiveness has declined.

On November 14 last year, medical staff at a hospital in Seoul administered a BA.4/5-based vaccine. Photo by Yonhap News

However, health authorities emphasize that the best approach in the current situation is to utilize the updated vaccines. On the morning of the 2nd, Jeong Ki-seok, head of the COVID-19 Special Response Team and member of the National Infectious Disease Crisis Response Advisory Committee, said in a briefing, "The bivalent vaccine has been proven to produce much more sufficient immune antibodies compared to previous vaccines, so we should use the bivalent vaccine to control the current outbreak," and urged, "Please get the bivalent vaccine to safely get through this winter."

Experts also believe that the updated vaccine will be effective against the new variant. The currently administered bivalent vaccine targets Omicron subvariants such as BA.4/5. Since the recently spreading XBB.1.5 variant is also an Omicron subvariant, it is predicted that the vaccine will have some degree of effectiveness.

Professor Jeong Jae-hoon of Gachon University’s Department of Preventive Medicine appeared on YTN's "News Live" on the 3rd and said, "When a new variant virus emerges, whether immunity is acquired through infection or vaccination, it tends to have some degree of immune evasion," adding, "The XBB.1.5 variant has characteristics that slightly evade the infection prevention effect of the currently administered bivalent vaccine, which is concerning."

Nevertheless, he explained, "So far, data show that there is no significant change in the severity rate compared to existing variants, and the effect of vaccines or infection in preventing severe illness will remain." He continued, "While the infection prevention effect of vaccines is maintained for a short period, the prevention effect against severe illness and death remains long-term even with variants, so vaccination is especially important for high-risk groups."