According to two new studies from the Case Western Reserve University School of Medicine, breakthrough COVID-19 cases resulting in infections, hospitalizations, and fatalities are considerably more common among cancer and Alzheimer’s patients.
According to the researchers, people with these disorders are more prone to infection in general and are among the population’s most sensitive to catastrophic health effects from COVID-19 infections. The studies come as the overall number of COVID-19 deaths in the United States has topped one million since the pandemic began.
Examining breakthrough infection rates in cancer patients
The first study, which was just published in JAMA (Journal of the American Medical Association) Oncology, looked at electronic health records to follow the number of breakthrough COVID infections, hospitalizations, and mortality rates among cancer patients who had been vaccinated.
According to the Centers for Disease Control (CDC) and Prevention, a “breakthrough infection” occurs when a completely vaccinated person acquires COVID. Lung, breast, colorectal, bladder, liver, endometrial, skin, prostate, thyroid, and blood cancers were among the 12 most prevalent cancers identified by the researchers.
These individuals were not previously afflicted and received COVID-19 immunizations between December 2020 and November 2021. The control group consisted of cancer-free participants who had been immunized.
The researchers matched cancer and non-cancer subjects for comorbidities, socioeconomic determinants of health, age and gender, and other factors before comparing breakthrough COVID-19 infections. The researchers looked at the records of over 636,000 vaccinated patients, including over 45,000 cancer patients.
“This study showed significantly increased risks for COVID-19 breakthrough infection in vaccinated patients with cancer, especially those undergoing active cancer care, with marked variations among specific cancer types,” said Rong Xu, professor of biomedical informatics at the School of Medicine and coauthor of this study.
Study coauthors include David Kaelber, professor at the School of Medicine and chief medical informatics officer at The MetroHealth System.
The team found:
- In vaccinated people with cancer, the overall risk of breakthrough COVID infections was 13.6%, compared to 4.9% in vaccinated people without cancer.
- People with pancreatic cancer (24.7%) had the highest incidence of breakthrough infections, followed by liver cancer (22.8%), lung cancer (20.4%), and colorectal cancer (17.5%).
- Thyroid cancer had a 10.3% chance of developing a breakthrough infection, endometrial cancer had an 11.9% chance, and breast cancer had an 11.9% chance.
- In research participants with cancer, the total probability of hospitalization following a breakthrough infection was 31.6%, compared to 3.9% in those without cancer.
- Following a breakthrough infection, the risk of death was 6.7%, compared to 1.3% in individuals without cancer.
This study showed significantly increased risks for COVID-19 breakthrough infection in vaccinated patients with cancer, especially those undergoing active cancer care, with marked variations among specific cancer types.
Professor Rong Xu
“Breakthrough infections in patients with cancer were associated with significant and substantial risks for hospitalizations and mortality. These results emphasize the need for patients with cancer to maintain mitigation practice, especially with the emergence of different virus variants and the waning immunity of vaccines,” said Xu and study coauthor, Nathan Berger, the Hanna-Payne Professor of Experimental Medicine at the School of Medicine.
Health outcomes in patients with Alzheimer’s disease following COVID infection
Researchers analyzed electronic health data in a second School of Medicine study to look at the rate of breakthrough COVID-19 infections in people with certain forms of dementia. The research was published in the journal Alzheimer’s & Dementia recently.
Because, while vaccines are beneficial, breakthrough infections are conceivable, and older persons with dementia were underrepresented in vaccine clinical trials, the researchers chose to look at data on breakthrough COVID-19 cases among those with dementia.
According to the study, the median age of the 37,706 participants in the clinical trial for the Pfizer-BioNTech vaccine was 52 years, and just 18 patients with dementia, or 0.05 percent, were enrolled.
The researchers looked at anonymised electronic health data from over 262,847 persons 65 and older who were vaccinated between December 2020 and August 2021 and had never been infected previously.
2,764 persons with Alzheimer’s disease, 1,244 with vascular dementia, 259 with Lewy body dementia, 229 with frontotemporal dementia, and 4,385 with mild cognitive impairment were diagnosed.
The researchers evaluated the overall risks of breakthrough infections in dementia patients who were vaccinated vs those who did not have any cognitive impairment.
The overall risk of breakthrough infections in vaccinated dementia patients ranged from 10.3 percent for Alzheimer’s disease to 14.3 percent for Lewy body dementia, which was significantly higher than the 5.6 percent in vaccinated older persons without dementia.
“Patients with dementia have a significantly higher rate of breakthrough COVID infections after vaccination than patients of the same age and risk factors other than dementia,” said Pamela Davis, the Arline H. and Curtis F. Garvin Research Professor at the School of Medicine.
“Therefore, continued vigilance is needed, even after vaccination, to protect this vulnerable population. Caregivers should consider ongoing masking and social distancing, as well as booster vaccines to protect these individuals.”
