Unequal burdens of COVID-19 infection: a nationwide cohort study of COVID-19-related health inequalities in Korea

Genome diversity of SARS-CoV-2 lineages associated with vaccination breakthrough infections in Addis Ababa, Ethiopia

BACKGROUND

Extensive vaccination campaigns against COVID-19 have played a significant role in controlling virus spread and preventing severe illness. This study focused on breakthrough infections in vaccinated individuals, raising concerns about vaccine effectiveness against SARS-CoV-2 variant immune escape, with particular attention to lineage distribution among vaccinated and unvaccinated individuals.

METHODS

A case-control study was conducted from January to April 2023, sequencing 298 samples from participants who tested positive for COVID-19 via rapid diagnostic test (RDT) from 22 health facilities, including vaccinated and unvaccinated cases. Besides clinical and epidemiological data, nasopharyngeal swabs were obtained, and reverse transcription quantitative polymerase chain reaction (RT-qPCR) was conducted to determine Cycle threshold (Ct) values, followed by whole genome sequencing of 298 samples fulfilling sequencing criteria to identify variants of concern and specific virus lineages.

RESULTS

Out of 298 samples sequenced, 281 fulfill quality for analysis with 44.8% (126) had received at least one COVID-19 vaccine dose, while 51.9% (146) were not vaccinated, and 3.2% (9) patients had no vaccination records. The analysis showed that all cases were of the Omicron variant, with the XBB.1.5 lineage being the most prevalent (38.4%), followed by FL.2 (9.3%) and XBB.1.9.1.2 (7.8%). The remaining 44.5% comprised a combination of 22 other lineages. The XBB.1.5 variant accounted for 51 (47.2%) cases among vaccinated individuals with at least one dose and 57 (52.8%) among unvaccinated, showing relatively similar prevalence across both groups. The viral load as indicated by the Ct value varied widely, with a significant appearance in the lower ranges (high viral load), suggesting active viral replication. Notably, 25% of samples exhibited high viral loads (Ct values 13-15), showing the high transmissibility of the XBB.1.5 lineage among both vaccinated and unvaccinated populations.

CONCLUSION

The findings emphasize the need for continuous genomic surveillance and regular vaccine updates to address emerging SARS-CoV-2 variants, particularly the immune-evasive XBB lineage. The high prevalence of variants like XBB.1.5 in breakthrough infection underscores the importance of adaptive vaccination strategies and next-generation vaccines to maintain efficacy. Ongoing monitoring of variant dynamics is crucial for informed public health responses, strengthening pandemic preparedness and future outbreak prevention.

Universal health coverage saves more lives among severely ill COVID-19 patients: A difference-in-differences analysis of individual patient data in South Korea

BACKGROUND

Universal health coverage (UHC) ensures affordability of a variety of essential health services for the general population. Although UHC could mitigate the harmful effects of coronavirus disease 2019 (COVID-19) on patients and their socioeconomic position, the debate on UHC's scope and ability to improve health outcomes is ongoing. This study aimed to identify the impact of UHC policy withdrawal on the health outcomes of South Korea's severely ill COVID-19 patients.

METHODS

We used a propensity score matching (PSM) and difference-in-differences combined model. This study's subjects were 44,552 hospitalized COVID-19 patients contributing towards health insurance claims data, COVID-19 notifications and vaccination data extracted from the National Health Information Database and the Korea Disease Control and Prevention Agency from 1 December 2020 to 30 April 2022. After PSM, 2460 patients were included. This study's exposures were severity of illness and UHC policy change. The primary outcome was the case fatality rate (CFR) for COVID-19, which was defined as death within 30 days of a COVID-19 diagnosis. There were four secondary outcomes, including time interval between diagnosis and hospitalization (days), length of stay (days), total medical expenses (USD) and the time interval between diagnosis and death (days).

RESULTS

After the UHC policy's withdrawal, the severely ill patients' CFR increased to 284 per 1000 patients [95% confidence interval (CI) 229.1-338.4], hospitalization days decreased to 9.61 days (95% CI -11.20 to -8.03) and total medical expenses decreased to 5702.73 USD (95% CI -7128.41 to -4202.01) compared with those who were not severely ill.

CONCLUSIONS

During the pandemic, UHC may have saved the lives of severely ill COVID-19 patients; therefore, expanding services and financial coverage could be a crucial strategy during public health crises.

The role of area deprivation index in health care disruptions among cancer survivors during the SARS-CoV-2 pandemic

OBJECTIVE

To examine the associations between demographic/medical and geographic factors with follow-up medical care and health-related quality of life (HRQoL) among cancer survivors during the SARS-CoV-2 pandemic.

STUDY DESIGN

Cross-sectional survey.

METHODS

An online survey was sent to cancer survivors between May 2020 and January 2021, exploring their experience with SARS-CoV-2, follow-up care, and HRQoL. PolicyMap was used to geocode home addresses. Both geographic and demographic/medical factors were examined for their associations with SARS-CoV-2 experience, follow-up care, and HRQoL (FACT-G7).

RESULTS

Geographic data were available for 9651 participants. Patients living in the highest area deprivation index (ADI) neighborhoods (most deprived) had higher odds of avoiding in-person general (odds ratio [OR] = 7.20; 95% confidence interval [CI] = 2.79-18.60), cancer (OR = 8.47; 95% CI = 3.73-19.30), and emergency (OR = 14.2; 95% CI = 5.57-36.30) medical care, as well as lower odds of using telemedicine (OR = 0.61; 95% CI = 0.52-0.73) compared to the lowest ADI group. Race/ethnicity was not associated with follow-up care after controlling for ADI. The effect of ADI on HRQoL was generally in the expected direction, with higher ADI being associated with worse HRQoL.

CONCLUSIONS

ADI influenced follow-up medical care more than age, race/ethnicity, or health insurance type. Healthcare providers and institutions should focus on decreasing barriers to in-person and telemedicine health care that disproportionally impact those living in more deprived communities, which are exacerbated by health care disruptions like those caused by the SARS-CoV-2 pandemic.

Risk factors for critical COVID-19 illness during Delta- and Omicron-predominant period in Korea; using K-COV-N cohort in the National health insurance service

BACKGROUND

This study evaluated the clinical characteristics of patients with COVID-19 in Korea, and examined the relationship between severe COVID-19 cases and underlying health conditions during the Delta (September 20, 2021 to December 4, 2021) and the Omicron (February 20, 2022 to March 31, 2022) predominant period.

METHODS

This study assessed the association between critical COVID-19 illness and various risk factors, including a variety of underlying health conditions, using multiple logistic regression models based on the K-COV-N cohort, a nationwide data of confirmed COVID-19 cases linked with COVID-19 vaccination status and the National Health Insurance claim information.

RESULTS

We analyzed 137,532 and 8,294,249 cases of COVID-19 infection during the Delta and the Omicron variant dominant periods, respectively. During the Delta as well as the Omicron period, old age (≥80 years) showed the largest effect size among risk factors for critical COVID-19 illness (aOR = 18.08; 95% confidence interval [CI] = 14.71-22.23 for the Delta; aOR = 24.07; 95% CI = 19.03-30.44 for the Omicron period). We found that patients with solid organ transplant (SOT) recipients, unvaccinated, and interstitial lung disease had more than a two-fold increased risk of critical COVID-19 outcomes between the Delta and Omicron periods. However, risk factors such as urban residence, underweight, and underlying medical conditions, including chronic cardiac diseases, immunodeficiency, and mental disorders, had different effects on the development of critical COVID-19 illness between the Delta and Omicron periods.

CONCLUSION

We found that the severity of COVID-19 infection was much higher for the Delta variant than for the Omicron. Although the Delta and the Omicron variant shared many risk factors for critical illness, several risk factors were found to have different effects on the development of critical COVID-19 illness between those two variants. Close monitoring of a wide range of risk factors for critical illness is warranted as new variants continue to emerge during the pandemic.