Adult SARS-CoV-2 (COVID-19) hospitalizations related to Omicron were less severe than Delta, and the Pfizer-BioNTech vaccine (also known as Comirnaty and BNT162b2*) remains effective in preventing not only hospitalization , but also serious patient outcomes associated with COVID-19, two new research studies have found.
The research, led by the University of Bristol, funded and carried out in collaboration with Pfizer Inc., as part of AvonCAP, is published in The Lancet Regional Health – Europe.
In the first article “Severity of Omicron (B.1.1.529) and Delta (B.1.617.2) SARS-CoV-2 infection among hospitalized adults: a prospective cohort study in Bristol, UK,” researchers evaluated whether Delta SARS-CoV-2 infection resulted in worse patient outcomes than Omicron SARS-CoV-2 infection, in hospitalized patients
The study aimed to provide more detailed data on patient outcomes, such as the need for respiratory support.
The research showed that Omicron infection resulted in less severe outcomes than Delta in hospitalized patients. Compared to Delta, Omicron-related SARS-CoV-2 hospitalizations were 58% less likely to need high-level oxygen, 67% less likely to need ventilatory support (such as a ventilator), or more critical care and 16% less. likely to have a hospital admission that lasted more than three days.
Dr Catherine Hyams, postdoctoral clinical researcher, principal investigator of the AvonCAP study and one of the lead authors of the study at the University of Bristol, said: “By discovering the reduced requirement for increased oxygen support and total positive pressure, including noninvasive ventilation, our analysis should contribute to future evaluations of hospital care and service planning.
“However, the impact of less severe Omicron-related hospitalization must be balanced against greater transmissibility and a higher overall number of infections with this variant.”
The research team suggests that there should be continuous assessment of the severity of new SARS-CoV-2 variants, along with careful planning of healthcare resources to prevent healthcare systems from being overwhelmed.
Dr Leon Danon, associate professor of infectious disease modeling and data analysis in the Department of Engineering Mathematics and one of the lead authors of the study, added: “These results have been published at a time when China is experiencing a resurgence of COVID-19 and may be useful in helping to understand what’s going on.”
The second article: ‘Effectiveness of BNT162b2 COVID-19 vaccination in preventing hospitalizations and serious illness in adults with SARS-CoV-2 variants Delta (B.1.617.2) and Omicron (B.1.1.529) between June 2021 and July 2022: A Prospective Study of Cases and Negative Controls’: Provides the first estimates of the effectiveness of the two- or three-dose Pfizer-BioNTech COVID vaccine against hospital admission for more than three days and against difficulty respiratory that requires oxygen or ventilatory support.
Many studies have reported the effectiveness of COVID-19 mRNA vaccines against hospitalization, but few have evaluated their effectiveness against clinically relevant measures of COVID-19 severity. Using detailed clinical data from the two Bristol Hospital Trusts – North Bristol NHS Trust (NBT) and University Hospitals Bristol and Weston NHS Foundation Trust (UHBW), researchers estimate the effectiveness of two or three doses of the Pfizer (original/monovalent) vaccine BioNTech against hospitalization for infection with Delta or Omicron SARS-CoV-2 variants.
The study showed that receiving two doses of the Pfizer-BioNTech vaccine can lead to an 83% reduction in the rate of hospitalization due to Delta SARS-CoV-2 infection, compared to those not vaccinated. Two doses also prevented serious hospital outcomes due to Delta SARS-CoV-2 infection, reducing the likelihood of a hospital admission lasting more than three days by 63%. The researchers also found that two doses of this vaccine reduced the risk of a patient needing increased oxygen or ventilatory support by 52% and 59%, respectively.
Receiving three doses of the Pfizer-BioNTech vaccine was also found to be effective in reducing the severity of Omicron infection, compared to those not vaccinated, even in older adults, reducing the risk of hospitalization for longer of three days with Omicron SARS-CoV-2 by 56%, and decreasing the risk of needing high-level oxygen or ventilatory support by 42% and 59%, respectively. This is further evidence that the Pfizer-BioNTech vaccine is effective in reducing hospital admissions due to SARS-CoV-2 infection from Delta and Omicron.
Dr. Anastasia Chatzilena, postdoctoral research associate in the Department of Mathematical Engineering and lead author of the study, said: “Our research has shown that the Pfizer-BioNTech vaccine provides effective protection against hospitalization for infection by Delta and Omicron and has significant benefits in terms of preventing serious illness, including critical care admission and respiratory failure.
“However, the benefit provided by vaccination declines over time, which appears to be more pronounced in older adults, so continued and careful monitoring of vaccine efficacy and severity of SARS- CoV-2 for emerging variants remains important.”
This research is part of AvonCAP, an ongoing collaborative surveillance project funded by Pfizer Inc., which records detailed information on every adult patient admitted to Bristol’s two largest NHS hospitals, NBT and UHBW, with symptoms, signs and/or X-ray evidence of acute lung disease.
* Pfizer-BioNTech vaccine (also known as Comirnaty and BNT162b2) is indicated for active immunization to prevent COVID-19 caused by SARS-CoV-2, in people 12 years of age and older.
magazine
The Lancet Regional Health – Europe
Research method
Observational study
Research topic
people
Title of the article
Severity of Omicron (B.1.1.529) and Delta (B.1.617.2) SARS-CoV-2 infection among hospitalized adults: a prospective cohort study in Bristol, UK
Publication date of the article
13-des-2022
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