2285P - Lower response to COVID-19 booster dose vaccination on cancer patients comparing to healthy controls

Background

Due to a compromised immune system, cancer patients are more prone to have a weaker response to COVID-19 vaccination, which can lead to a worst outcome. Thus it is crucial to evaluate the immunological response of cancer patients to booster doses of the vaccine to stratify the patients accordingly and provide a better care.

Methods

Vaccinated cancer patients from the Portuguese Oncology Institute of Porto, under active cancer treatment with different types of solid tumours (SL) and liquid tumours (LT) were included to study the potential differences in the response to COVID-19 booster dose vaccine according to tumour type. Humoral immune response to the booster dose of the COVID-19 vaccine was evaluated in patients’ serum samples analysing IgG levels against SARS-CoV-2 Spike (S) protein. We also analysed the IgG levels against SARS-CoV-2 Nucleocapsid (N) protein to address previous contact with the virus. The first cohort of patients collected samples before the booster dose and 3 and 6 months after (cohort 1, N=54, SL=44, LT=10) and the other cohort collected samples only 3 and 6 months after booster dose (cohort 2, N=71, SL=45, LT=26). A group of vaccinated healthy individuals (N=83) was also analysed, and they collected samples at 3 and 6 months post-boost.

Results

Regarding cohort 1, for solid tumours, we observed that IgG S levels increased 3 months after boost (p<0.001) and remained high at 6 months post-boost (p<0.001) when compared to pre-boost. One the other hand, the hematologic tumours demonstrated a weak response to vaccination since IgG S levels remained very low 3 and 6 months after the boost. When comparing 3 months post-boost in both cohorts and healthy individuals, we observed that the healthy individuals had the strongest IgG S response, followed by the solid and, lastly, the hematologic tumours. In fact, the difference between solid and haematological tumours was quite significant (p=0.017).

Conclusions

We verified that the type of tumour may influence COVID-19 vaccination efficacy since solid cancer patients had a better response to SARS-CoV-2 vaccination when compared to haematological cancer patients. Moreover, as expected, healthy individuals have a stronger immune response when compared to cancer patients.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Rui Medeiros, Júlio Oliveira.

Funding

AstraZeneca.

Disclosure

All authors have declared no conflicts of interest.