Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Aug 15;37(32):e252.
doi: 10.3346/jkms.2022.37.e252.

Breakthrough COVID-19 Infection During the Delta Variant Dominant Period: Individualized Care Based on Vaccination Status Is Needed

Chan Mi Lee  1   2 , Eunyoung Lee  1   2 , Wan Beom Park  1 , Pyoeng Gyun Choe  1 , Kyoung-Ho Song  1   3 , Eu Suk Kim  1   3 , Sang-Won Park  1   4
Affiliations

Breakthrough COVID-19 Infection During the Delta Variant Dominant Period: Individualized Care Based on Vaccination Status Is Needed

Chan Mi Lee et al. J Korean Med Sci. .

Abstract

Background: The clinical features of coronavirus disease 2019 (COVID-19) patients in the COVID-19 vaccination era need to be clarified because breakthrough infection after vaccination is not uncommon.

Methods: We retrospectively analyzed hospitalized COVID-19 patients during a delta variant-dominant period 6 months after the national COVID-19 vaccination rollout. The clinical characteristics and risk factors for severe progression were assessed and subclassified according to vaccination status.

Results: A total of 438 COVID-19 patients were included; the numbers of patients in the unvaccinated, partially vaccinated and fully vaccinated groups were 188 (42.9%), 117 (26.7%) and 133 (30.4%), respectively. The vaccinated group was older, less symptomatic and had a higher Charlson comorbidity index at presentation. The proportions of patients who experienced severe progression in the unvaccinated and fully vaccinated groups were 20.3% (31/153) and 10.8% (13/120), respectively. Older age, diabetes mellitus, solid cancer, elevated levels of lactate dehydrogenase and chest X-ray abnormalities were associated with severe progression, and the vaccination at least once was the only protective factor for severe progression. Chest X-ray abnormalities at presentation were the only predictor for severe progression among fully vaccinated patients.

Conclusion: In the hospitalized setting, vaccinated and unvaccinated COVID-19 patients showed different clinical features and risk of oxygen demand despite a relatively high proportion of patients in the two groups. Vaccination needs to be assessed as an initial checkpoint, and chest X-ray may be helpful for predicting severe progression in vaccinated patients.

Keywords: Breakthrough Infection; COVID-19; Oxygen Therapy; SARS-CoV-2; Severe Progression.

PubMed Disclaimer

Conflict of interest statement

The authors have no potential conflicts of interest to disclose.

Figures

Fig. 1
Fig. 1. Study setting. A total of 438 patients were enrolled, 188 of whom were unvaccinated and 250 of whom were vaccinated. The vaccinated group was divided into the fully vaccinated group and the partially vaccinated group.
Fig. 2
Fig. 2. Requirement for oxygen therapy at admission and during hospitalization among the unvaccinated (n = 188) and fully vaccinated groups (n = 133). The results are presented as the number of individuals in the UV group and the FV group. Among the 188 patients in UV group, 35 patients required oxygen at admission and 31 patients out of the other 153 patients (20.3%, 31/153) experienced clinical aggravation to need new oxygen requirement. Among the 133 patients in FV group, 13 patients required oxygen at admission and 13 patients out of the other 120 patients (10.8%, 13/120) experienced clinical aggravation to need new oxygen requirement.
UV = unvaccinated, FV = fully vaccinated.
See this image and copyright information in PMC

References

    1. Polack FP, Thomas SJ, Kitchin N, Absalon J, Gurtman A, Lockhart S, et al. Safety and efficacy of the BNT162b2 mRNA COVID-19 vaccine. N Engl J Med. 2020;383(27):2603–2615. - PMC - PubMed
    1. Baden LR, El Sahly HM, Essink B, Kotloff K, Frey S, Novak R, et al. Efficacy and safety of the mRNA-1273 SARS-CoV-2 vaccine. N Engl J Med. 2021;384(5):403–416. - PMC - PubMed
    1. Falsey AR, Sobieszczyk ME, Hirsch I, Sproule S, Robb ML, Corey L, et al. Phase 3 safety and efficacy of AZD1222 (ChAdOx1 nCoV-19) COVID-19 vaccine. N Engl J Med. 2021;385(25):2348–2360. - PMC - PubMed
    1. Yi S, Kim JM, Choe YJ, Hong S, Choi S, Ahn SB, et al. SARS-CoV-2 delta variant breakthrough infection and onward secondary transmission in household. J Korean Med Sci. 2022;37(1):e12. - PMC - PubMed
    1. Wi YM, Kim SH, Peck KR. An outbreak of breakthrough infections by the SARS-CoV-2 delta variant in a psychiatric closed ward. J Korean Med Sci. 2022;37(4):e28. - PMC - PubMed

Substances

Supplementary concepts