ABSTRACT
Background: The ASCO Registry was created to analyze the impact of COVID-19 (COVID) on treatment (Tx) and outcomes of patients (pts) with cancer. Vaccination questions were added in 2021, enabling examination of breakthrough cases i.e., SARS-CoV-2 infection after vaccination. Methods: The Registry includes pts who test positive for SARS-CoV-2 and have clinically evident cancer receiving Tx or resected cancer on adjuvant Tx <12 months since surgery at the time of the positive test. Practices report data on COVID vaccine type and dates, positive SARS-CoV-2 test date, and subsequent Tx. Breakthrough cases were defined as 1) > 35 days after 1st Pfizer dose, 2) > 42 days after 1st Moderna dose, 3) > 14 days after 1st Janssen dose, or 4) > 42 days after 1st unknown vaccine dose. Data submission cutoff for all practices was February 2, 2022. Summary statistics and exact binomial 95% confidence intervals (CIs) were calculated. Results: This analysis reports on 231 pts with breakthrough cases. Median age is 68 years and 57% of pts are over age 65. Of 73 pts with non-metastatic solid tumors, 19% were hospitalized. Of 74 with metastatic solid tumors, 39% were hospitalized. Of 75 with B-cell malignancies, 32% were hospitalized. Of 9 with other hematologic malignancies, 56% were hospitalized. While the fraction of patients in the ASCO registry with breakthrough cases who were hospitalized remained fairly constant throughout 2021 (approximately 40%), those with breakthrough cases occurring in the last month of 2021 and early 2022 had a lower hospitalization rate (approximately 20%), which is consistent with less severe cases of COVID-19 in patients infected with the omicron variant (the predominant variant in the US in Dec 2021-Jan 2022) (Table). The majority of breakthrough cases occurred more than 6 months after initial vaccination (71%) and the median time to breakthrough infection from initial vaccination was 7.3 months (IQR: 5.6 9.9). The Registry continues to accrue cases and additional vaccine data;analysis will be updated with most current vaccination data for possible Annual Meeting presentation. Conclusions: Hospitalizations among patients with cancer and breakthrough COVID in the ASCO Registry occur at a high rate, particularly among patients with advanced cancers and hematologic malignancies. This decrease in recent months is likely due to increased incidence of the Omicron variant that resulted in milder COVID symptoms among those infected. A majority of SARS-CoV-2 infections occurring six months or more after vaccination suggests waning vaccine efficacy over time that could be impacted by additional doses.
ABSTRACT
Background: The availability of safe and effective COVID-19 vaccines has enabled protections against serious outcomes from SARS-CoV-2 infection. The ASCO Registry provides an opportunity to study the rate of vaccine uptake among patients (pts) with cancer who had SARS-CoV-2 infection prior to availability of vaccines. Methods: Participating US medical oncology practices identify pts eligible for inclusion: pts with a positive SARS-CoV-2 test and, at the same time, either (a) or (b) cancer-free less than 12 months (i.e., in complete remission or post-resection) and receiving adjuvant treatment. Registry data were extracted on 2/4/22. Pts in this analysis had a SARS-CoV-2 positive test between 3/1/2020 and 12/31/2020 and at least one clinical encounter on or after 1/1/21, documenting receipt or not of 1st and 2nd vaccine shots. Pts lacking data on vaccination status in their medical records were excluded from analysis. When the exact date of 1st vaccine shot was known, the primary endpoint was number of days from 1/1/21 to 1st shot date. If the exact date of 1st shot was unknown, date was categorized as within 7 days from the clinical encounter, 2-4 weeks, or more than 1 month prior. Summary statistics and 95% confidence intervals (CIs) were calculated using Kaplan-Meier methods. Results: The Registry included 1260 pts with SARS-CoV-2 infection in 2020. Time to vaccination (described using cumulative incidence) across age categories is shown in Table, with 1/1/21 as the baseline. Median time to vaccination ranged from 63 days in the oldest pts (> 80 years of age) to 220 days in the youngest pts (< 45 years of age). Differences in rates of vaccination uptake were most pronounced in the early months (Jan - Mar) and diminished in April and beyond. Conclusions: Older pts with cancer who were infected with SARS-CoV-2 in 2020 received COVID-19 vaccinations in 2021 at higher rates than those of younger ages. Delayed uptake by younger aged pts at outset could be related to lack of clarity on pts with cancer qualifying for early vaccine access and state policies on availability.