Rates of hospitalizations and mortality from COVID-19 were more than 4 times lower in 2022 compared to 2021, as the virus become less severe with new mutations, a recent study found.
COVID-19 disease phenotypes are becoming less severe with each mutation, which may explain why patients with cancer are at their lowest risk of severe COVID-19 disease outcomes since the beginning of the SARS-CoV-2 pandemic, according to a paper published in Scientific Reports. However, patients with cancer are still more than twice as likely to have hospitalization or mortality from COVID-19 as those without the disease.
“The reduction in the severity of disease phenotype is likely attributable to the great strides taken by health care professionals to adapt cancer care, including access to vaccination and reconfigurations of treatment programs and wider health care services,” the study authors wrote.
United Kingdom (UK) investigators analyzed changing case-outcome rates over the course of the pandemic to understand internal and external risk factors that may lead to severe COVID-19 outcomes (hospital assessment, case-hospitalization, intensive care unit (ICU) admission, and case-mortality) in patients with cancer.
“It is widely acknowledged that the risk from SARS-CoV-2 is heterogenous,” the study authors wrote. “For people living with cancer, the risks are dependent on a combination of intrinsic patient factors, cancer factors (subtypes and treatments), COVID-19 measures (primary vaccination, boosters, early treatment programs, access to intensive care units), and additionally by external factors such as the virulence of SARS-CoV-2 variants. The interactions of these factors vary over time as pandemics evolve, with changes to both the intrinsic and extrinsic risk factors.”
COVID-19-related hospitalizations decreased from 30.58% to 7.45% between 2021 and 2022, which is approximately 4.10 times lower, and mortality dropped from 20.53% to 3.25%, which is approximately 6 times lower. Other than lung cancer and hematologic malignancies, patients with most cancer subtypes experienced reduced COVID-19 case outcomes. Patients with hematologic malignancies had a case mortality rate of 5.68%.
There were also discrepancies in case mortality based on age. Patients aged 80 years and older had a case-mortality rate of 10.32%, whereas patients aged 18 to 79 years had an average case-mortality rate of 2.83%.
Investigators collected data from The UK Coronavirus Cancer Programme (UKCCP)—a nationwide COVID-19 cancer database—and assessed the case outcome rates of 198,819 patients with cancer who tested positive for COVID-19 between November 2020 through August 2022. They compared their case outcome rates to the case outcomes rates of 18,188,573 people without cancer who tested positive for COVID-19.
A primary limitation of the study was the focus on disease severity instead of number of COVID-19 cases, according to the authors. In addition, hospitals and ICUs changed the clinical guidelines for treating patients with cancer during the pandemic. Further, the findings could underestimate COVID-19 risk and diagnostic tests were not used to evaluate risk. Investigators should gear future research toward understanding how to reduce the risk for patients with cancer or other conditions, such as immunosuppression after transplant.
People with cancer generally have reduced immunity and worse responses to the COVID-19 vaccines and boosters. Those who receive vaccination do not get the same durable protection as people without cancer, and their risk of hospitalization or mortality from COVID-19 is still higher, which may be partly due to B and T cell-depleting cancer therapies, according to the study.
“The elevated risks of severe COVID-19 outcomes therefore need to be weighed against the oncological benefits of cancer treatment,” the study authors wrote. “The trends of SARS-CoV-2 outcome severity must be monitored and further efforts to reduce excess risk experienced by patients with cancer remain important.”
Ionescu M, Tilby M, Little M, et al. A population-scale temporal case–control evaluation of COVID-19 disease phenotype and related outcome rates in patients with cancer in England (UKCCP). Sci Rep 13, 11327 (2023). Doi: https://doi.org/10.1038/s41598-023-36990-9