Seroprevalence and infection fatality rate of the SARS-CoV-2 Omicron variant in Denmark: A nationwide serosurveillance study

Article Infectious Diseases

Increased risk of infection with SARS-CoV-2 Omicron BA.1 compared with Delta in vaccinated and previously infected individuals, the Netherlands, 22 November 2021 to 19 January 2022

Dirk Eggink et al.

Summary: Infection with the Omicron SARS-CoV-2 variant is increasing rapidly worldwide. Vaccination or previous infection-induced immunity is less effective against the Omicron variant compared to the Delta variant.

EUROSURVEILLANCE (2022)

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Article Infectious Diseases

Reduced risk of hospitalisation among reported COVID-19 cases infected with the SARS-CoV-2 Omicron BA.1 variant compared with the Delta variant, Norway, December 2021 to January 2022

Lamprini Veneti et al.

Summary: A study found that the Omicron variant of COVID-19 has a 73% reduced risk of hospitalization compared to the Delta variant. Omicron cases who had received two doses of the vaccine 7-179 days before diagnosis had a lower risk compared to Delta (66% vs 93%), while those who received three doses had a similar risk reduction (86% vs 88%).

EUROSURVEILLANCE (2022)

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Article Immunology

Estimation of SARS-CoV-2 Infection Fatality Rate by Age and Comorbidity Status Using Antibody Screening of Blood Donors During the COVID-19 Epidemic in Denmark

Kathrine Agergard Kaspersen et al.

Summary: The study shows that the infection fatality rate (IFR) of healthy individuals under 51 years old without comorbidities is very low. However, the IFR increases with age and comorbidity. Additionally, there was a decline in IFR from the first to the second wave of the epidemic.

JOURNAL OF INFECTIOUS DISEASES (2022)

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Article Medicine, General & Internal

Early assessment of the clinical severity of the SARS-CoV-2 omicron variant in South Africa: a data linkage study

Nicole Wolter et al.

Summary: According to data analysis from South Africa, individuals infected with the omicron variant have a lower likelihood of hospitalization compared to those infected with non-omicron variants. Furthermore, individuals infected with the omicron variant have a lower odds of severe disease compared to individuals infected with the earlier delta variant.

LANCET (2022)

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Letter Medicine, General & Internal

Breakthrough infections with SARS-CoV-2 omicron despite mRNA vaccine booster dose

Constanze Kuhlmann et al.

LANCET (2022)

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Review Hematology

Current challenges of severe acute respiratory syndrome coronavirus 2 seroprevalence studies among blood donors: A scoping review

Sahar Saeed et al.

Summary: The scoping review of SARS-CoV-2 seroprevalence studies among blood donors revealed that most studies showed seroprevalence rates below 10%, and less than one-fifth of the studies were standardized to reflect the general population demographics. Variances in study designs and methodologies were identified as contributing factors to the heterogeneity in seroprevalence rates, alongside differences in community transmission and public health policies.

VOX SANGUINIS (2022)

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Article Microbiology

Evaluation of the Performance of a Multiplexed Serological Assay in the Detection of SARS-CoV-2 Infections in a Predominantly Vaccinated Population

Michael Asamoah-Boaheng et al.

Summary: Different thresholds are required for optimal test performance in vaccinated and unvaccinated individuals, especially for detecting COVID-19 within the preceding 9 months. Overall, specificity was significantly higher among unvaccinated individuals.

MICROBIOLOGY SPECTRUM (2022)

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Article Infectious Diseases

Long-term detection of SARS-CoV-2 antibodies after infection and risk of re-infection

Bo Langhoff Honge et al.

Summary: The study found that 94.2% of healthy blood donors develop antibodies after being infected with SARS-CoV-2, and a lack of detectable antibodies is associated with reinfection.

INTERNATIONAL JOURNAL OF INFECTIOUS DISEASES (2022)

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Article Medicine, General & Internal

Comparative analysis of the risks of hospitalisation and death associated with SARS-CoV-2 omicron (B.1.1.529) and delta (B.1.617.2) variants in England: a cohort study

Tommy Nyberg et al.

Summary: The Omicron variant shows lower severity compared to Delta, especially in terms of hospital admission and death, with significant variations by age. Unvaccinated cases experience a larger reduction in intrinsic severity, while vaccinated cases experience reduced vaccine effectiveness. Booster vaccination with mRNA vaccines provides over 70% protection against hospitalization and death in breakthrough Omicron infections.

LANCET (2022)

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Article Multidisciplinary Sciences

Increased risk of SARS-CoV-2 reinfection associated with emergence of Omicron in South Africa

Juliet R. C. Pulliam et al.

Summary: This study provides two methods for monitoring reinfection trends in routine surveillance data. The results suggest immune evasion by the Omicron variant in previously infected individuals in South Africa, and there has been an increase in the risk of having a third infection since mid-November 2021.

SCIENCE (2022)

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Article Public, Environmental & Occupational Health

Seroprevalence of Infection-Induced SARS-CoV-2 Antibodies — United States, September 2021–February 2022

Kristie E.N. Clarke et al.

MMWR-MORBIDITY AND MORTALITY WEEKLY REPORT (2022)

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Article Medicine, General & Internal

The displacement of the SARS-CoV-2 variant Delta with Omicron: An investigation of hospital admissions and upper respiratory viral loads

Amary Fall et al.

Summary: The study found that the Omicron variant is more likely to cause breakthrough infections in vaccinated individuals compared to Delta, but admissions are less frequent. However, admitted patients might develop severe diseases comparable to Delta. Efforts to reduce Omicron transmission are necessary due to the increased numbers of infections leading to a high hospitalization rate.

EBIOMEDICINE (2022)

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Article Immunology

Estimation of SARS-CoV-2 Infection Fatality Rate by Real-time Antibody Screening of Blood Donors

Christian Erikstrup et al.

Summary: This study aimed to estimate previous SARS-CoV-2 infections and the population-based IFR through nationwide real-time seroprevalence surveying among Danish blood donors. The seroprevalence was found to be 1.9% and the estimated IFR in patients <70 years was 89 per 100,000 infections.

CLINICAL INFECTIOUS DISEASES (2021)

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Article Immunology

The Duration, Dynamics, and Determinants of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Antibody Responses in Individual Healthcare Workers

Sheila F. Lumley et al.

Summary: In this study, it was found that anti-nucleocapsid antibodies against SARS-CoV-2 decline within a few months, with higher titers associated with longer duration. On the other hand, anti-spike IgG remained stably detected. Factors such as age, ethnicity, and symptom presentation also had an impact on antibody levels.

CLINICAL INFECTIOUS DISEASES (2021)

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Article Infectious Diseases

Epidemiological characterisation of the first 785 SARS-CoV-2 Omicron variant cases in Denmark, December 2021

Laura Espenhain et al.

Eurosurveillance (2021)

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Letter Infectious Diseases

Serological markers of SARS-CoV-2 infection; anti-nucleocapsid antibody positivity may not be the ideal marker of natural infection in vaccinated individuals

Niamh Allen et al.

JOURNAL OF INFECTION (2021)

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Article Microbiology

Comparison of 16 Serological SARS-CoV-2 Immunoassays in 16 Clinical Laboratories

Lene H. Harritshoj et al.

Summary: This study evaluated the diagnostic accuracy of 15 commercial and one in-house anti-SARS-CoV-2 assays in Danish laboratories. Most total antibody and IgG assays showed high sensitivity and specificity, with some overlap in confidence intervals. IgM results were more variable, with one assay demonstrating higher sensitivity and specificity.

JOURNAL OF CLINICAL MICROBIOLOGY (2021)

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Article Public, Environmental & Occupational Health

Prevalence of SARS-CoV-2 antibodies in Denmark: nationwide, population-based seroepidemiological study

Laura Espenhain et al.

Summary: Seroprevalence studies conducted in Denmark in 2020 have shown an increase in seroprevalence estimates throughout the year, especially in the 12-29 age group and metropolitan areas. Hospitalization rates were significantly higher in older age groups, and although many seropositive individuals were asymptomatic, loss of taste/smell was a specific symptom.

EUROPEAN JOURNAL OF EPIDEMIOLOGY (2021)

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Article Medicine, General & Internal

Covid-19 Breakthrough Infections in Vaccinated Health Care Workers

Moriah Bergwerk et al.

Summary: Among fully vaccinated health care workers, breakthrough infections with SARS-CoV-2 were correlated with neutralizing antibody titers during the peri-infection period. Most breakthrough infections were mild or asymptomatic, although persistent symptoms did occur.

NEW ENGLAND JOURNAL OF MEDICINE (2021)

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Article Medicine, General & Internal

Evolution of antibody responses up to 13 months after SARS-CoV-2 infection and risk of reinfection

Floriane Gallais et al.

Summary: The study revealed a triphasic kinetic model of SARS-CoV-2 antibodies in convalescent individuals, showing long-term persistence and reduced risk of reinfection. Vaccination significantly increased antibody titers, enhancing protection against variants.

EBIOMEDICINE (2021)

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Article Immunology

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection Fatality Rate Among Elderly Danes: A Cross-sectional Study on Retired Blood Donors

Ole Birger Pedersen et al.

Summary: By studying retired blood donors and national COVID-19 survey data, reliable population-based infection fatality rate estimates for individuals aged 70 and above were obtained, revealing that the COVID-19 infection fatality rate for this age group is 65 times higher than for those aged 18-69.

CLINICAL INFECTIOUS DISEASES (2021)

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Article Multidisciplinary Sciences

Long-term specific IgG response to SARS-CoV-2 nucleocapsid protein in recovered COVID-19 patients

Jira Chansaenroj et al.

Summary: This study monitored the long-term immune response to SARS-CoV-2 infection in recovered COVID-19 patients, finding that the anti-N IgG seropositivity rate started to decline 6-12 months after symptom onset. Additionally, the anti-N IgG sample/cutoff index was positively correlated with age and negatively correlated with the interval between symptom onset and blood sampling.

SCIENTIFIC REPORTS (2021)

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Article Hematology