ABSTRACT
Background: Adults and childrenwith cancer are susceptible to severe SARS-CoV-2 disease. Vaccination is protective;data beyond initial response and regarding effect of booster doses are lacking in cancer patients. Method(s): The SerOzNET study assesses SARS-CoV-2 vaccine response in haematological and solid cancer patients aged 5 and older. Patients are recruited pre dose 1 and receive standard BNT162b2 (Pfizer) or ChadOx1-S (AstraZeneca) vaccine. Blood is taken at baseline and after each dose. Neutralizing antibody (NAb) titre, absolute antibody titre (Abbott), T cell response (IFN-gamma) and epigenetics are analysed. Clinical data are collected. Patients are followed for up to 3 months beyond dose 5. Result(s): 105 children (64% haem, 36% solid cancers) and 399 adults (35% haem, 65% solid cancers) were enrolled. In adults, NAb response rate increased after dose 3 (Post 2: 40% haem, 87%solid;Post 3:70%haem,97%solid). Post dose 2, predictors of nonresponse were ChadOx1-S vaccine (OR 3 p = .02), haem cancer (OR 14 p < .001), ECOG >=1 (OR 2.6 p = .01) and steroids (OR 5 p = .01). Post dose 3, only haem cancer predicted non-response (OR 16). IFN-gamma response is available for a subset, detectable in 41/90 (46%) postdose 1, 78/96 (81%) post-dose 2 and 35/42 (83%) post-dose 3;without significant difference between haem and solid cancer. In children, NAb response post dose 2 is available for 50 patients. Response rate between haem (19/31, 61%) and solid patients (13/19, 68%) was similar. IFN-gamma response post dose 2 was also similar: (14/22, 63%) vs solid patients (12/14, 85%) (p = .25). Analysis is ongoing. Conclusion(s): Response to two doses of SARS-CoV-2 vaccine is suboptimal in patients with cancer. The third priming dose is integral, with significantly higher response rates observed. 36% of children did not develop neutralizing antibodies post dose 2;subsequent doses are likely to be important for young patients.
ABSTRACT
Background: COVID-19 disease is more severe in unvaccinated cancer patients compared with the general population. There is limited data regarding clinical efficacy of vaccination in these patients. Method(s): SerOzNET (ACTRN12621001004853) is a prospective observational cohort study of adults and children with cancer receiving COVID-19 vaccination. The primary endpoint is serological response. An important secondary endpoint is outcome of COVID-19 infection after vaccination. We report self- and clinician reported COVID-19 infections. Result(s): Of 395 adults (20 years +), 74 (19%) reported COVID-19 infection over mean duration on study of 259 days. 71 (97%) had received 2 vaccine doses, 51 (69%) received 3+ doses. 21 (28%) had antiviral treatment. 62 (84%) had symptoms, 7 (9%) required hospitalisation, 0 required ICU admission or died due to COVID-19. Of 113 children/adolescents (5-19 years), 31 (27%) reported COVID-19 infection over mean duration on study of 215 days. 28 (90%) had received 2 vaccination doses, and 12 (39%) received 3+ doses. 23 (74%) had symptoms, 8 (25%) required hospitalisation, 2 (6%) had antiviral therapy, 0 required ICU admission or died due to COVID-19. Pediatric pts with COVID-19 infection had increased risk of hospitalisation compared with adults (p=0.03). Hematological cancer pts had non-significant but numerically higher rates of hospitalisation (Table). [Formula presented] Conclusion(s): Pts with cancer are likely to be exposed to COVID-19, with infection rates similar to the wider population. Vaccination appears to protect against ICU admission in cancer patients. However, 9% of adults and 25% of children with cancer required hospitalisation for COVID-19, demonstrating increased severity of symptoms compared to the general population. Higher rates of infection and hospitalisation in pediatric pts may be partly attributable to the lower proportion of children who had received a 3rd vaccination dose at the time of infection. Clinical trial identification: ACTRN12621001004853. Legal entity responsible for the study: Monash Health. Funding(s): Cancer Australia (Australian Federal Government) Victorian Cancer Agency (Victorian State Government, Australia) Leukaemia Foundation (Foundation, Australia). Disclosure: All authors have declared no conflicts of interest. Copyright © 2022