Poster Presentation Clinical Oncology Society of Australia Annual Scientific Meeting 2023

SOCCER: Study of Oncological patients reCeiving COVID-19 vaccines whilst undergoing systemic thERapy for malignancy  (#461)

Kristin Hsu 1 , Tiffany Foo 2 , Monique Swan 1 , David Gordon 1 , Anna Rachelle Mislang 1
  1. Flinders Medical Centre, Adelaide, SOUTH AUSTRALIA, Australia
  2. The Queen Elizabeth Hospital, Adelaide, SA, Australia

Introduction

During the coronavirus SARS-CoV-2 (COVID-19) pandemic, the high rates of infection, hospitalization and mortality prompted an urgent development of an effective vaccine. The first 2 vaccines that were developed were the BNT162b2 (Pfizer/BioNTech vaccine) and the ChAdOx1-S (Oxford/AstraZeneca COVID-19) vaccine.

In this study, we assessed the efficacy of the COVID-19 vaccine in patients with solid cancers on active anti-cancer therapy; and measured their antibody responses following a minimum of 2 doses of the two available COVID-19 vaccines in Australia at time of study.

Study Design and Methods

This study was a prospective study of patients with solid organ cancers who were on active systemic anti-cancer treatment and who received the COVID-19 vaccine. Enrolled patients would undergo blood collections: Baseline pre-1st vaccination, day 21 Pre-2nd dose, 3-4 weeks post 2nd dose, 3 months post 2nd dose, 6 months post 2nd dose. Bloods were tested for SARS-CoV-2 specific spike protein and spike protein receptor binding domain (RBD) antibody responses by ELISA and flow cytometry assays (Elecsys® Anti-SARS-CoV-2 S). Marked elevation of antibody titres observed post vaccination, would suggest a strong humoral immune response to vaccination.

Results

We recruited 23 patients from Flinders Medical Centre – 16 participants had Astra Zeneca, 6 had Pfizer, 1 had Moderna vaccine. 11 participants completed the 5 required blood tests for the study. None of the 23 patients had past covid infection. Seroconversion rate after 1st dose of vaccine was 60% and antibody titres exponentially increased over time and after 2nd dose of vaccination. 100% seroconversion was achieved after dose 2 and maintained up to 6 months.

Conclusion

Rates of seroconversion were 100% for the 17 patients that had antibody levels taken after 2nd vaccine dose, consistent with other studies. Hence, this study supports the current recommendations that immunocompromised patients should have the vaccine and are able to mount immune response to the mRNA spike protein.

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  2. Therapeutic Goods Administration (TGA) (2023) Covid-19 vaccines regulatory status, Therapeutic Goods Administration (TGA). Available at: https://www.tga.gov.au/covid-19-vaccine-provisional-registrations (Accessed: 07 August 2023).
  3. Lee ARYB, Wong SY, Chai LYA, Lee SC, Lee M, Muthiah MD, et al. Efficacy of COVID-19 vaccines in immunocompromised patients: A systematic review and meta-analysis. medRxiv. 2021:2021.09.28.21264126.