[A summarized unofficial version of the press release]

COVID-19 vaccination significantly

reduces the severity of illness

In the delta period, the intrinsic severity of COVID-19 was one-sixth lower in the vaccinated group, and during the omicron period, it was one-third lower compared to the unvaccinated.

Osong, 5th February 2024 ━ The Korea Disease Control and Prevention Agency (KDCA) released a study in BMC Infectious Diseases, an international open access journal, analyzing changes in the intrinsic severity of SARS-CoV-2 with emerging variants through a comparison between people with and without immunity from vaccination or natural infection.

The study indicates that, in the pre-delta, delta, and omicron periods, the unvaccinated group* experienced case severity rates** (CRSs) of 2.12%, 5.51%, and 0.94%, respectively, with case fatality rates (CFRs) of 0.60%, 2.49%, and 0.63%.

* Initially infected COVID-19 confirmed cases who did not receive a COVID-19 vaccine (excluding reinfected cases)

** Case severity rate: the proportion of severely ill cases and deaths among confirmed cases; case fatality rate: the proportion of deaths among confirmed cases

However, the CRS in the completely vaccinated group (second dose) decreased by one-sixth (1/6) during the delta-dominant period and one-third (1/3) during the omicron-dominant period compared to the unvaccinated group, proving vaccination's effectiveness in preventing severe outcomes with emerging variants.

In addition, the study shows that despite mitigated severity, the medical burden among older individuals remains high* due to a consistently elevated proportion of severe cases and deaths during the omicron period.

* Percentage of severely ill cases and deaths aged 60 years or older: 85.0% of severely

ill cases and 94.0% of deaths

The study compares the severity of COVID-19 between vaccinated individuals and those without immunity from vaccination or natural infection. Its significance is emphasized by the academically acknowledged results, providing clear evidence supporting the preventive effects of vaccination.

Commissioner Jee of the KDCA stated, “The study demonstrates that the severity of COVID-19 lessens among vaccinated individuals, even when they face changes in severity due to new variants. I expect that vaccination will have a continuing positive impact on minimizing the health damage inflicted by COVID-19 against future variants.”

She also emphasized, “the currently administered XBB.1.5 COVID-19 vaccines are highly effective in preventing the HK.3 and JN.1 variants, now circulating nationwide. The government has scheduled January 26–February 8 for a Lunar New Year holiday vaccination campaign to forestall severe outcomes. It is paramount to receive COVID-19 vaccines before traveling, participating in family gatherings, and visiting high-risk facilities, including nursing homes, to stave off severe illness and deaths."

* For detailed information, please refer to the press release written in the Korean language in the file attached below.