One-year breakthrough SARS-CoV-2 infection and correlates of protection in fully vaccinated hematological patients

Category	Detail
Condition	Breakthrough SARS-CoV-2 infection in fully vaccinated patients with hematological disorders
Key Mechanisms	Poor humoral response and impaired cellular immunity increase risk and severity of breakthrough infections despite vaccination
Target Population	Patients with hematological disorders fully vaccinated against SARS-CoV-2
Care Setting	Multicenter hematology and infectious disease outpatient and inpatient settings

Mortality from COVID-19 in hematological patients dropped from >25% early in the pandemic to <10% after vaccination.
High rates of hospitalization (66.4%) and ICU admission (21.3%) persist in breakthrough infections despite vaccination and serological response.
Prospective registry of 1551 fully vaccinated hematological patients monitored humoral response and breakthrough infection incidence over one year.

Monitor SARS-CoV-2-reactive IgG antibodies (anti-N and anti-S IgG) at 3–6 weeks, 3, 6, and 12 months post-vaccination using ELISA or chemiluminescence immunoassay.

Vaccination with full schedule (two doses for RNA vaccines or one dose for adenoviral vector vaccines) is critical to reduce severity and mortality.
Booster doses should be recorded and evaluated for impact on breakthrough infection risk.

Prospective serological monitoring is recommended to assess humoral response kinetics and identify patients at higher risk of breakthrough infection.
Regular follow-up for breakthrough infection symptoms and hospitalization risk is essential.

Patients with hematological disorders have increased risk of severe breakthrough COVID-19 due to impaired immunity.
Breakthrough infections may occur multiple times with different SARS-CoV-2 variants despite vaccination.

Fully vaccinated patients with various hematological disorders enrolled in a national prospective registry.

Vaccination reduces mortality but breakthrough infections remain frequent and severe; serological response monitoring informs risk stratification.

Obtain informed consent and ethical approval for serological monitoring in hematological patients.
Use standardized antibody assays normalized to WHO standards for consistent interpretation.
Address logistical challenges to ensure regular serological testing and follow-up.
Consider both humoral and cellular immunity status when assessing patient risk.
Maintain vigilance for breakthrough infections even in vaccinated patients and provide appropriate clinical support.

Clinical Scorecard: Incidence of Breakthrough SARS-CoV-2 Infections After One Year and Protective Factors in Fully Vaccinated Patients with Hematological Disorders