Long-term transition of antibody titers in healthcare workers following the first to fourth doses of mRNA COVID-19 vaccine: Comparison of two automated SARS-CoV-2 immunoassays.

Anti-spike receptor binding domain (S-RBD) antibody against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which best correlates with virus-neutralizing antibody is useful for estimating the period of protection and identifying the timing of additional booster doses. Long-term transition of the S-RBD antibody titer and the antibody responses among healthy individuals remain unclear. In the present study, therefore, we monitored the S-RBD antibody titers of 16 healthcare workers every 4 weeks for 76 weeks after vaccination with a fourth dose of mRNA-1273 (Moderna) following three doses of BNT162b2 (Pfizer/BioNTech) using two commercial automated immunoassays (Roche and Abbott). Two antibody responses to the vaccine were similar with an up-down change before and after the second (weeks 3), third (weeks 40) and fourth (week 72) vaccinations, but the titer did not fall below the assay's positivity threshold in any individual. The peak level of the geometric mean titer (GMT) in the Roche assay was highest after the third vaccination, and that in Abbott assay was highest after the fourth vaccination but almost equal to that after the third vaccination. Both the geometric mean fold rise (GMFR) demonstrated by the Roche and Abbott assays were highest after the third vaccination. Antibody titers determined by the Roche and Abbott assays showed a positive strong correlation (correlation coefficient: 0.70 to 0.99), but the ratio (Roche/Abbott) of antibodies demonstrated by both assays increased 0.46- to 8.26-fold between weeks 3 and 76. These findings will be helpful for clinicians when interpreting results for SARS-CoV-2 antibody levels and considering future vaccination strategies.

Two-Year Seroprevalence Surveys of SARS-CoV-2 Antibodies among Outpatients and Healthcare Workers in Ehime, Japan.

We conducted two-year seroprevalence surveys of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies among outpatients and healthcare workers (HCWs) at Ehime University Hospital. Data were collected for outpatients and HCWs in June 2020 (1st survey), December 2020 (2nd survey), July 2021 (3rd survey), and December 2021 (4th survey), focusing on demographics, occupation, and the seroprevalence of anti-SARS-CoV-2 antibodies. Blood samples were obtained from randomly selected outpatients who visited our hospital for medical care and HCWs undergoing regular medical checks with opt-out informed consent. SARS-CoV-2 antibody positivity was evaluated using two laboratory-based quantitative tests. The total number of participants enrolled was 6,369 (1st survey: 1,000 outpatients and 743 HCWs, 2nd survey: 1,000 outpatients and 407 HCWs, 3rd survey: 1,000 outpatients and 804 HCWs, 4th survey: 1,000 outpatients and 415 HCWs). The prevalence of SARS-CoV-2 antibodies among outpatients and HCWs was 0-0.1% and 0-0.124% during the research period, respectively, and changed little over time. These findings suggest that the magnitude of COVID-19 infection during the pandemic among outpatients and HCWs in this rural hospital might have been small.

Axillary Lymph Node Swelling After COVID-19 Booster Vaccination: Japanese Case Report and Literature Review.

BACKGROUND/AIM: COVID-19 has been a global pandemic for more than 2 years, and vaccination against COVID-19 using an mRNA vaccine is widespread. The COVID-19 vaccination can cause specific side-effects, such as axillary lymph node swelling; therefore, breast oncologists should pay attention to such occurrences. Initially, only two COVID-19 vaccinations were planned; however, in some countries third or fourth vaccines have been administered. Here, we present a female case who developed axillary lymph node swelling after her third vaccination. We have also reviewed the literature regarding this side-effect after a third or fourth COVID-19 vaccination. CASE REPORT: A 64-year-old woman who came to our clinic regarding a mammography abnormality in her left breast. She had no palpable mass, but a left breast mass was shown by mammography, and ultrasonography and magnetic resonance imaging indicated a hamartoma. At 2 months after her second COVID-19 vaccination when she underwent these tests, she had no axillary lymph node swelling. We planned a follow-up after 6 months. At her next visit, by chance, she underwent ultrasonography 14 days after she received a third COVID-19 vaccination, and a swollen axillary lymph node was observed. CONCLUSION: Axillary lymph node swelling can occur after a third COVID-19 vaccination. Therefore, breast oncologists will have to consider this side-effect of COVID-19 vaccination when diagnosing breast tumors.

Timing and Duration of Axillary Lymph Node Swelling After COVID-19 Vaccination: Japanese Case Report and Literature Review.

BACKGROUND/AIM: COVID-19 vaccination is now performed in most of the world to limit the spread of the disease. The first mRNA vaccine was approved in clinical settings and has specific side effects including axillary lymph node swelling, which can be misdiagnosed as breast cancer metastasis. The timing of axillary lymph node swelling and its duration are unclear. Here, we present a Japanese case and review of the existing literature. CASE REPORT: We report the case of a 67-year-old woman with breast calcification. She had regular follow ups in our hospital for this calcification and received ultrasonography of the breast and axilla at every visit. She visited 6 months before having her COVID-19 vaccination, and 7 days and 6 months after the first COVID-19 vaccination. She had a swollen axillary lymph node 7 days after the first vaccination, which although it was improved, remained for 6 months. CONCLUSION: Axillary lymph node swelling occurred 7 days after vaccination and remained up to 6 months after it.

COVID-19 Screening of Breast Cancer Patients During Treatment: A Single Center Experience in Japan.

Background/Aim: Breast cancer treatment mainly involves interventional methods such as surgical resection and chemotherapy. How to best perform these treatments during the COVID-19 pandemic remains to be established. Patients and Methods: Patients with breast cancer who received SARS-CoV-2 PCR screening before cancer treatment from December 2020 to April 2021 were included. PCR screening was performed within 72 hours of the scheduled admission time and treatment. Results: A total of 19 tests in 15 patients were analysed. Fourteen cases displayed no symptoms, and five cases had some symptoms. COVID PCR tests were negative in all cases. Conclusion: COVID-19 screening can ensure that breast cancer patients do not miss scheduled treatments as a result of the pandemic. Diagnosis of patients with symptoms that are shared by COVID-19 infection, chemotherapy, and breast cancer recurrence must be performed carefully.

Axillary Lymph Node Swelling Mimicking Breast Cancer Metastasis After COVID-19 Vaccination: A Japanese Case Report and Literature Review.

BACKGROUND/AIM: COVID-19 started to spread as a pandemic in December 2019 and COVID-19 vaccination has been initiated worldwide. The efficacy of vaccination has been scientifically proven, but it might cause axillary lymph node swelling. To diagnose patients with axillary lymph node swelling caused by COVID-19 vaccination, we herein reviewed existing literature on this symptom. CASE REPORT: We report the case of a 70-year-old woman with a breast tumour. She had undergone cecum cancer surgery and regular computed tomography (CT). During breast tumour follow-up, she received scheduled CT that indicated severe axillary lymph node swelling mimicking breast cancer metastasis. We performed aspiration biopsy cytology of that lymph node, and determined this was not cancer metastasis but an effect of the COVID-19 vaccine. We confirmed this diagnosis at one month after computed tomography showed that the lymph node swelling had improved. CONCLUSION: Axillary lymph node swelling can occur after COVID-19 vaccination. Therefore, it is important to consider the effect of the COVID-19 vaccination on axillary lymph node swelling when diagnosing breast tumours.