Health & Wellbeing

Yale study identifies those at risk of breakthrough COVID-19 infections

Yale study identifies those at...
Research indicates severe COVID-19 in vaccinated individuals is still very rare
Research indicates severe COVID-19 in vaccinated individuals is still very rare
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Research indicates severe COVID-19 in vaccinated individuals is still very rare
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Research indicates severe COVID-19 in vaccinated individuals is still very rare

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

8 comments
8 comments
Lynn Wahl
Clarification needed: 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.

Are those 14 patients out of the 54 vaccinated people, or out of the whole 1,000 sample set? If they are out of the vaccinated group, how does that compare with the unvaccinated group? If they are out of the whole sample, was there any difference in percentage between vaccinated/unvaccinated? It is quite difficult to do an A/B comparison without groups A and B being labelled.
MeToo
It would be helpful if you mentioned the survival rate of the whole group. I hate it when the media intentionally omits that.
Karmudjun
Great article Rich.
This isn't the forum for me to address a few of the issues I have with this Lancet write up - or your write up. I am glad you shared the age weighted breakthrough findings, due to a combination of age related diminished immune function and length of time from full vaccination (antibodies wane slowly from the maximal level). There are a few articles in equally prestigious medical journals that discuss the risk of breakthrough infections with more of a researcher to practitioner tone. Lay people need to understand what Hyung Chun et al. are saying and not read more or less into it as we frequently see in blogs and opinion pieces - or on social media.
jsopr
While breakthrough hospitalizations are indeed rare, it is not the case that "breakthrough infections are very rare." Vaccine protection against infection is maybe 50-75%, meaning that the case rate among the vaccinated is around half or a quarter that of the unvaccinated. When case rates are high among the unvaccinated (as in the US right now), they will also be fairly high among the unvaccinated. The big difference is that the infected vaccinated folks will be highly protected against severe disease including hospitalization and death.
melmark
This data was before Delta, therefore moot.
christopher
"half were completely asymptomatic" - so vaccinated people turn into super-spreaders having no idea they're even infecting others? Great.
martinwinlow
So, basically, a group of vaccinated very old, very sick people went to hospital and some had COVID and some died. Brilliant.
Calcfan
Isn't mentioning having diabetes rather incomplete without mentioning for how long and if well controlled or not. It seems that uncontrolled diabetes would be the major factor.