Neutralizing activity against Omicron subvariants BA.1, BA.2, and BA.4/5 following the third SARS-CoV-2 vaccination
Jina Yun1, Bora Kim1, Hyuk Kim1
1Division of Hematology-Oncology, Department of Medicine, Soonchunhyang University, Bucheon Hospital, Bucheon, Gyeonggi-do, South Korea.
Objectives:
Despite the availability of bivalent vaccines targeting both the ancestral SARS-CoV-2 strain and Omicron subvariants, vaccination rates remain low in South Korea. This study aims to evaluate the neutralizing activity against Omicron subvariants following the third SARS-CoV-2 vaccination in patients undergoing chemotherapy, as well as to assess the need for additional vaccinations.
Methods:
Between April and November 2022, the authors assessed the neutralizing activity of the third SARS-CoV-2 vaccine dose in 63 patients undergoing chemotherapy using an ELISA-based surrogate Virus Neutralization Test (sVNT). The authors examined the influence of factors such as prior COVID-19 infection, cancer type (solid vs. hematologic malignancy), type of chemotherapy regimen (cytotoxic chemotherapy, targeted therapy, immune checkpoint inhibitors), and vaccine type (homologous vector, homologous mRNA, heterologous) on neutralizing activity.
Results:
Among the 57 patients included in the analysis, 26 (45.6 %) had a history of SARS-CoV-2 infection. Patients with hematologic cancers exhibited lower neutralizing antibody responses compared to those with solid tumors for Omicron subvariants BA.1 (24.44 % vs. 71.68 %, p = 0.020), BA.2 (48.22 % vs. 94.59 %, p = 0.006), and BA.4/5 (24.76 % vs. 78.06 %, p = 0.046). Among uninfected patients (n = 31), sVNT inhibition scores were significantly lower across all subvariants (e.g., 5.89 % for BA.1 vs. 58.11 % in infected, p = 0.0025). Treatment delays due to infection were observed in 9 patients (17.75 days on average). Although no deaths were directly attributed to infection, one patient died due to disease progression following a treatment delay caused by the infection.
Conclusions:
Patients undergoing chemotherapy displayed weak neutralizing responses against Omicron subvariants, especially those with hematologic cancers or no prior infection. Consequently, it is crucial to actively recommend additional vaccinations with bivalent or newly developed vaccines for these vulnerable patients.
Insights
Patients undergoing chemotherapy show weak neutralizing responses to Omicron subvariants after their third SARS-CoV-2 vaccine dose. Additional vaccinations are crucial for immunocompromised individuals, especially those with hematologic cancers or no prior infection.
Area of Science:
- Immunology
- Oncology
- Virology
Background:
- Low vaccination rates in South Korea despite bivalent vaccine availability.
- Patients undergoing chemotherapy are a vulnerable population for SARS-CoV-2 infection.
- Omicron subvariants pose a significant challenge due to immune evasion.
Purpose of the Study:
- To evaluate neutralizing activity against Omicron subvariants after the third SARS-CoV-2 vaccination in chemotherapy patients.
- To assess the need for additional vaccinations in this cohort.
- To identify factors influencing vaccine response in cancer patients.
Main Methods:
- ELISA-based surrogate Virus Neutralization Test (sVNT) used on 63 chemotherapy patients.
- Assessment of neutralizing activity after the third SARS-CoV-2 vaccine dose.
- Analysis of factors: prior infection, cancer type, chemotherapy regimen, and vaccine type.
Main Results:
- Hematologic cancer patients showed significantly lower neutralizing antibody responses against Omicron subvariants BA.1, BA.2, and BA.4/5 compared to solid tumor patients.
- Uninfected patients had substantially lower sVNT inhibition scores across all subvariants compared to infected patients.
- Treatment delays due to COVID-19 infection occurred in 9 patients, averaging 17.75 days.
Conclusions:
- Chemotherapy patients exhibit diminished neutralizing responses to Omicron subvariants.
- Patients with hematologic malignancies and those without prior SARS-CoV-2 infection are particularly susceptible.
- Active recommendation of additional bivalent or novel vaccine doses is essential for this high-risk group.
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