Yale study identifies those at risk of breakthrough COVID-19 infections
A small but robust study from Yale University researchers is offering insights into the characteristics of severe COVID-19 infections in fully vaccinated individuals. Although these kinds of breakthrough infections are very rare, the research helps doctors understand which patients may be most at-risk of hospitalization despite vaccination status.
The new study, published in The Lancet Infectious Diseases, looked at around 1,000 hospitalized COVID-19 patients admitted to the Yale New Haven Health System between March and July this year. Only 54 of those admissions were fully vaccinated, affirming the strong protection vaccines offer against severe COVID-19.
Of those 54 fully vaccinated patients, around half were completely asymptomatic, having been admitted to hospital for other reasons and their COVID-19 status only being picked up through incidental SARS-CoV-2 testing. Fourteen patients ended up critically ill, requiring oxygen support, and four ended up in intensive care. Three of these patients ultimately died from COVID-19.
The median age of those 14 severely ill COVID-19 patients was 80, and several pre-existing co-morbidities were noted in the study. Twelve of those patients were suffering cardiovascular disease, nine were overweight, seven had diabetes and seven had some kind of pre-existing lung disease.
Hyung Chun, senior author on the study, says the vast majority of fully vaccinated patients infected with SARS-CoV-2 experience very mild disease. This research, he notes, is vital in helping understand which factors increase a fully vaccinated person’s risk of severe COVID-19.
“These [breakthrough] cases are extremely rare, but they are becoming more frequent as variants emerge and more time passes since patients are vaccinated,” says Chun. “Identifying who is more likely to develop severe COVID-19 illness after vaccination will be critical to ongoing efforts to mitigate the impact of these breakthrough infections.”
Importantly, this particular study spans a period of time before the Delta variant became predominant in the United States. Chun says is unclear at this stage whether Delta leads to more severe breakthrough infections.
“It’s clear that the vaccines are highly effective, and without them we would be facing a much deadlier pandemic,” says Chun. “As effective as the vaccines are, with emerging variants and increasing cases of breakthrough infections, we need to continue to be vigilant in taking measures such as indoor masking and social distancing.”
The new research was published in The Lancet Infectious Diseases.
Source: Yale News