Northwestern Medicine investigators continue to study COVID-19, from comparing mortality rates between SARS-CoV-2 variants to examining the effectiveness of maternal vaccination in protecting infants and combating COVID-19 misinformation on social media.
COVID-19 Mortality: Delta vs. Omicron
A recent study from the United Kingdom found that risk of COVID-19 related death was significantly lower in people infected with the SARS-COV-2 Omicron subvariant BA.1 than in those infected with the earlier Delta variant.
According to a Northwestern Medicine commentary published in The BMJ, the study provides the most conclusive evidence to date that Omicron infection was less deadly than Delta when controlling for a number of key variables including sociodemographic status, pre-existing health conditions and previous immunity.
Ramon Lorenzo Redondo, PhD, assistant professor of Medicine in the Division of Infectious Diseases, Egon A Ozer, MD, PhD, ’08 GME, assistant professor of Medicine in the Division of Infectious Diseases and director of the Center for Pathogen Genomics and Microbial Evolution, and Judd Hultquist, PhD, assistant professor of Medicine in the Division of Infectious Diseases, were co-authors of the paper.
The referenced study combined SARS-CoV-2 genomic surveillance data with mortality records to compare Omicron’s BA.1 subvariant fatality rate with Delta. Additionally, in order to control for possible confounders, the study included census data, vaccination dates, and other standardized measures for over one million U.K. adults who tested positive for SARS-CoV-2 in December 2021, the period when both Omicron and Delta co-circulated in the UK. Overall, the study found that COVID-19 mortality rates were 66 percent lower in people infected with Omicron than in those with Delta.
In the commentary, Lorenzo Redondo, Ozer and Hultquist urged investigators to further investigate the causes of this lower mortality rate in order to better assess the risks of emerging variants. The authors also underscored a need for improved strategies in communicating risk and implementing appropriate public health responses. Lastly, they stressed the importance of continuing to develop, optimize, and deploy systems that integrate molecular surveillance, demographic, epidemiological, and clinical datasets to allow for timely research.
“Investment in this infrastructure will be critical for the continued response to COVID-19 and for future pandemic preparedness,” the authors wrote.
Maternal COVID-19 Vaccination and Hospitalization Risk for Infants
Pregnant individuals who were vaccinated with two doses of an mRNA COVID-19 vaccine experienced a reduced risk of hospitalization and severe illness for COVID-19 in their newborn children, according to findings published in The New England Journal of Medicine.
Previous work has shown that pregnant individuals who are vaccinated for COVID-19 can transfer SARS-COV-2 antibodies to their unborn children, which can reduce an infant’s risk of hospitalization if they’re infected with COVID-19.
In the current study, the investigators enrolled infants younger than six months — 537 hospitalized for COVID-19 (case infants) and 512 hospitalized without COVID-19 (control infants) — from 30 hospitals across the U.S. Among these infants, 16 percent of case infants and 29 percent of control infants were born to mothers who were fully vaccinated against COVID-19 during pregnancy.
Maternal vaccination against COVID-19 hospitalization among these infants was 52 percent effective during the surge of the Delta variant (July 1, 2021, to December 18, 2021) and 38 percent effective during Omicron (December 19, 2021, to March 8, 2022).
Additionally, maternal vaccination was 69 percent effective when vaccination occurred after 20 weeks of pregnancy and 38 percent effective during the first 20 weeks of pregnancy.
“The finding that the risk of hospitalization, and in particular, hospitalization in an ICU, was reduced among infants whose mothers had been fully vaccinated during pregnancy provides evidence of additional benefits of maternal vaccination beyond those previously reported for the mother,” the authors wrote.
This work was supported by the Centers for Disease Control and Prevention under a contract with Boston Children’s Hospital.
Twitter Health Amplifiers Combat COVID-19 Misinformation
At the beginning of the COVID-19 pandemic, when false information about the virus began to spread on Twitter, physicians and scientists from Northwestern Medicine and other institutions banded together to combat the deadly misinformation and disinformation and support one another when they ultimately were attacked online for doing so.
They formed a new type of professional organization — the health professional amplifier — to tweet accurate health and safety information about COVID-19 and amplify one another “to combat misinformation and drown out some of the noise,” said Regina Royan, MD, MPH, clinical instructor of Emergency Medicine and lead author of a new Northwestern Medicine paper published in the Journal of Medical Internet Research, explaining the genesis of these groups and a member of the Illinois-based health professional amplifier, IMPACT (Illinois Medical Professional Action Collaborative Team).
In the publication, Royan and fellow medical professionals explain how successful this group has been and why it is an effective tool to disseminate accurate medical information and combat disinformation while minimizing the harm related to personal and professional harassment that can come with social media advocacy.
“The pandemic has been really taxing for health professionals,” Royan said. “In addition to the emotional toll caring for these very sick patients, particularly in the early waves of the pandemic, the politicization around COVID-19 added another layer of stress for many of us. One thing we highlight in this paper is that these kinds of groups can be a safe space for health professionals to talk about issues like harassment on social media to keep the fight against misinformation going.”
Other Northwestern authors include Seth Trueger, MD, MPH, associate professor of Emergency Medicine, and medical student Tricia Pendergrast. IMPACT co-founder Amisha Wallia, MD, MS, assistant professor of Medicine in the Division of Endocrinology, is a member of Northwestern’s Institute for Public Health and Medicine.
This work was supported by the National Heart, Lung, and Blood Institute grant 3U54HL143541-02S2 through the RADx-Tech program and the National Institute of Biomedical Imaging and Bioengineering through the Center for Innovation in Point of Care Technologies for HIV/AIDS at Northwestern (C-THAN; 3U54EB027049-02S1).
Assessing SARS-COV-2 Vaccine Breakthrough Infections
Adults infected with SARS-COV-2 at varying stages of vaccination demonstrated reduced duration of viral shedding and symptoms compared to unvaccinated individuals, according to findings published in the journal Open Forum Infectious Diseases.
“Our study illustrates how vaccination can impact virus dynamics in earlier variants of concern of SARS-CoV-2, before Delta and Omicron. As we move into an era of developing and implementing Omicron-specific vaccines, we expect them to have a similar impact on Omicron sub-variant SARS-CoV-2 dynamics and infectiousness,” said Chad Achenbach, ’02 MD, ’02 MPH, associate professor of Medicine in the Division of Infectious Diseases, of Preventive Medicine, and a co-author of the study.
In this study, investigators evaluated the dynamics of viral shedding and overall symptoms in 23 adults primarily infected with Alpha and Gamma variants of SARS-CoV-2 who were at varying stages of vaccination; six were fully vaccinated and 17 were partially vaccinated. Sixty individuals who were unvaccinated and infected with SARS-CoV-2 were also enrolled. Patient data was collected at two study sites (Northwestern University and the University of Illinois Urbana-Champaign) through daily nasal swabs and saliva samples, along with symptom reporting.
Overall, the investigators found that vaccinated individuals were less likely to be shedding infectious virus and shedding virus for a shorter period of time compared with unvaccinated individuals. Vaccinated participants also reported fewer days of symptoms.
Other Northwestern Medicine co-authors include Chao Qi, ’99 PhD, director of Microbiology in the Department of Pathology, Egon A Ozer, MD, PhD, ’08 GME, assistant professor of Medicine in the Division of Infectious Diseases, Judd Hultquist, PhD, assistant professor of Medicine in the Division of Infectious Diseases, Ramon Lorenzo Redondo, PhD, assistant professor of Medicine in the Division of Infectious Diseases, Claudia Hawkins, MD, MPH, associate professor of Medicine in the Division of Infectious Diseases, and Robert Murphy, MD, ’81 GME, the John Philip Phair Professor of Infectious Diseases and executive director of the Robert J. Havey, MD Institute for Global Health.
“This study provides evidence of the role of SARS-CoV-2 vaccines not only in reducing the severity of the disease, but also the infectiousness and symptoms of individuals with breakthrough infections. We hope to continue to observe similar findings as Omicron-specific vaccines are rolled out in the coming weeks,” Achenbach said.
This work was supported by the National Heart, Lung, and Blood Institute at the National Institutes of Health grant 3U54HL143541-02S2 through the RADx-Tech program and the National Institute of Biomedical Imaging and Bioengineering through the Center for Innovation in Point of Care Technologies for HIV/AIDS at Northwestern (C-THAN; 3U54EB027049-02S1).