Who is most at risk?
- Although very few deaths or post-vaccination hospitalizations have occurred in the UK, several groups were at higher risk than others, according to a new study.
- New tool identifies people most at risk of serious consequences from breakthrough SARS-CoV-2 infections. SARS-CoV-2 is the coronavirus that causes COVID-19.
- The hope is that this information will enable healthcare professionals and patients to make more informed decisions regarding COVID-19 strategies.
Before vaccines became available, British experts developed the QCOVID risk assessment tool to identify those most at risk of dying or being hospitalized from COVID-19. The tool added 1.5 million people to the National list of protected patients and helped authorities prioritize vaccinations.
However, there remains a residual risk of breakthrough infections for people who are fully or partially vaccinated. To identify those most at risk for major infections, researchers at the University of Oxford in the UK published an article presenting an updated QCOVID tool called QCOVID3.
The new QCOVID3 tool has identified several groups of vaccinated people who are at particular risk of dying or being hospitalized due to SARS-CoV-2 infection.
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Co-author of the article Dr Julia Hippisley-Cox, professor of clinical epidemiology and general medicine at the University of Oxford, explains:
âThe UK was the first place to implement a vaccination program and has some of the best clinical research data in the world. We have developed this new tool using the QResearch database to help the [National Health Service] identify which patients are most at risk of becoming severe despite vaccination for a targeted intervention.
Dr Hippisley-Cox adds, âThis new tool can also inform physician-patient discussions about the level of risk to facilitate shared decision-making.
The authors of the article point out that few vaccinated people died or had to be hospitalized 14 days or more after vaccination. This is probably enough time for immunity to develop.
Co-author of the article Dr Aziz Cheikh, professor of research and development in primary care and director of the Usher Institute at the University of Edinburgh in the UK, says:
âThis huge national study of more than 5 million people vaccinated with [two] doses across the UK revealed that a small minority of people remain at risk of hospitalization and death from COVID-19. Our risk calculator helps identify those who remain most at risk after vaccination. “
The paper now appears in the
Dr Sheikh says: ‘Our new QCOVID tool, developed with the help of experts from across the UK, has been designed to identify high-risk people who may benefit from interventions such as vaccine booster doses. or new treatments such as monoclonal antibodies, which can help reduce the risk of progression of SARS-CoV-2 infection to severe COVID-19 results. “
More than 6 million datasets of vaccinated adults have been studied using the QCOVID3 algorithm. Of these adults, more than 5 million had received both doses of the vaccine.
The data sets included 2,031 COVID-19-related deaths and 1,929 COVID-19-related hospitalizations, of which 4% and 3.7%, respectively, occurred 14 days after the second vaccination.
The QCOVID3 algorithm identified the following groups as being most at risk, in descending order:
- people with Down’s syndrome
- people who have had a kidney transplant
- people with sickle cell disease
- nursing home residents
- people receiving chemotherapy
- people who have recently had a bone marrow transplant or solid organ transplant
- people living with HIV or AIDS
- people with dementia
- people with Parkinson’s disease
- people with several rare neurological diseases
- people with cirrhosis
Pakistani and Indian individuals vaccinated were twice as likely as white individuals.
The authors of the article speculate that this finding may reflect other non-physiological factors beyond the scope of research.
They say, âThese ethnic disparities in COVID-19 outcomes may represent residual differential exposure (related for example to behavior, lifestyle, household size and occupation) more than mechanisms of differential sensitivity, although we also recognize that being vaccinated may change behavior (and exposure) more in some groups than in others.
There were so few deaths or hospitalizations among those who received two doses of the vaccine in the study that, write the authors, “most of the information on associations between predictors and mortality comes from individuals who received only one dose “.
They believe the post-full vaccination figures were too low to draw conclusions about the likelihood of getting a breakthrough infection after the second dose compared to the first dose.
The researchers also do not distinguish between the different vaccines given to the cohort, nor do they establish any association between them and the reported results.
The authors also cite a few other limitations. These include the short time to follow-up after vaccination – up to 70 days – and the inclusion of many partially vaccinated individuals. During the study, they also did not take into account the results associated with the different variants of SARS-CoV-2 due to insufficient data.
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