Poster Presentation Asia-Pacific Vaccine and Immunotherapy Congress 2024

Humoral and cellular responses to SARS-CoV-2 vaccination in Australian adults with cancer. (#166)

Amy Body 1 2 , Elizabeth Ahern 1 , Luxi Lal 1 , Stephen Opat 2 3 , Michael F Leahy 4 , Noemi Fuentes-Bolanos 5 , Bhavna Padhye 6 , Nada Hamad 7 , Corey Smith 8 , Stuart Turville 9 , William Rawlinson 10 11 , Raina MacIntyre 9 , Sriganesh Srihari 8 , Eva Segelov 12
  1. Medical Oncology, Monash Health, Clayton, VIC, Australia
  2. Monash University, Clayton, VIC, Australia
  3. Haematology, Monash Health, Clayton, VIC, Australia
  4. Haematology, Royal Perth Hospital, Perth, WA, Australia
  5. Oncology, Sydney Children's Hospital, Sydney, NSW, Australia
  6. Paediatric Oncology, Westmead Hospital, Sydney, NSW, Australia
  7. Haematology, St Vincent's Hospital, Sydney, NSW, Australia
  8. QIMR Berghofer, Brisbane, QLD, Australia
  9. The Kirby Institute, University of New South Wales, Sydney, NSW, Australia
  10. NSW Health Pathology, Sydney, NSW, Australia
  11. University of New South Wales, Sydney, Australia
  12. Faculty of Medicine University of Bern and Department of Radiation Oncology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland

Background

Patients with cancer have increased risk of severe outcomes from SARS-CoV-2 infection. Vaccination incompletely reduces risk; vaccinated cancer patients have a higher chance of hospitalisation and death due to COVID-19 than healthy controls. Neutralising antibodies are a correlate of protection. SerOzNET is a prospective study seeking to elucidate nuanced detail about immune response to vaccination in Australians with cancer.

Methods

Participants with cancer were enrolled prior to first SARS-CoV-2 vaccination. Comprehensive information regarding diagnosis and treatment was collected. Blood was sampled at baseline and serial timepoints until 3 months after 5th vaccine dose, and analysed for neutralising antibody response, quantitative IgG response (Abbott), and T-cell cytokine production (IFN-y).

Results

There were 395 patients enrolled, mean age 57 years (range 20-85), 60% were female. Cancer diagnoses were solid organ cancers (SOC) in 257/395 patients (65%), and haematological cancers (HC) in 138/395 (35%). Cytotoxic chemotherapy was received by 49% of SOC and 62% of HC patients. Neutralising antibody was detectable in SOC and HC respectively in 84% and 43% after 2 doses, 96% and 65% after 3 doses, 98% and 69% after 4 doses and 100% and 90% after 5 doses. T cell IFNγ response was detected in SOC and HC respectively in 72% and 49% after 2 doses, 75% and 90% after 3 doses and 82% and 87% after 4 doses. On multivariate analysis, antibody response rate was higher in SOC (vs HC, OR 1.38, 1.06-1.8, p=0.017), and lower in patients on anti-B cell therapies (OR 0.19, 0.13-0.27, p<0.001). T cell response was predicted by SOC (vs HC, OR 1.76, 1.27-1.43, p=0.001). There was a non-significant trend toward negative effect of chemotherapy on antibody (OR 0.81, 0.64-1.03) and T cell response (OR 0.8, 0.6-1.06). Median absolute IgG titre was lower at serial timepoints in patients with HC, or on steroids, and higher with hybrid immunity post infection. B cell count correlated with IgG titre and was lower in patients on anti-B-cell therapies.

Conclusion

Most patients with cancer develop protective antibodies after SARS-CoV-2 vaccination, proportion of responders increases after each dose. After 3 doses, almost all patients with SOC respond however a third of HC patients do not. T cell response may provide an additional means of protection for patients with suboptimal antibody response; however, HC patients have reduced T cell and antibody response, placing them at higher risk. Patients with HC may require additional boosters and precautions against SARS-CoV-2 infection.