Study finds COVID-19 vaccines prevent hospitalizations, deaths

Karen Bouffard
The Detroit News

Vaccination against COVID-19 significantly reduces the risk of hospitalization and death in people who come down with the illness after getting the shots, according to a Beaumont Health study published Thursday.

In the largest-scale study yet to focus on the effects of vaccination on patients hospitalized with COVID-19, researchers looked at data from 11,834 people who tested positive in the emergency departments at Beaumont's eight hospitals from Dec. 15, 2020, to April 30, 2021. 

They found that 1% of the patients who tested positive had been fully vaccinated, and the fully vaccinated group had a 96% lower rate of emergency visits or  hospitalizations than the unvaccinated group.

"The overwhelming majority of patients (who tested positive,) 92%, were unvaccinated," lead author Dr. Amit Bahl, an emergency medicine physician and director of emergency ultrasound for Beaumont Hospital in Royal Oak, said Thursday. 

"So 129 out of approximately 12,000 encounters were fully vaccinated," he said. "If you're vaccinated, you don't go to the emergency room, you don't go to the hospital, you don't get admitted to the ICU."

Bahl noted that the time period studied predated the arrival in Michigan of the delta variant, which is known to be more highly transmissible than earlier iterations of the virus. He said his team plans to do a similar study now that delta has become the predominant variant in the state, but he expects the results to be similar.

There were 10 different variants present in Michigan during the time the study was conducted, Bahl said, and the vaccine was very effective in preventing emergency visits, hospitalization and deaths in people infected by those. 

In addition, current hospitalization numbers at Beaumont Health Hospitals show a pattern similar to what was found in the study, Bahl noted. 

Of 214 patients hospitalized with COVID-19 systemwide on Thursday, 160 were unvaccinated and 54 were fully vaccinated. And 90% of the patients who were ventilated hadn't had the shots.

"The vast majority of people who are hospitalized and who are having severe outcomes, those patients are unvaccinated — and 96% of them have delta," Bahl said. "So while I can't say we've investigated and studied that aspect of it yet, I'm fairly confident that those would be the same conclusions." 

Bahi said the scale of the study and the diversity of the population covered by Beaumont's eight hospitals mean the results can be applicable to people across Michigan and nationwide. Data from about 2,000 encounters with patients whose emergency visits were unrelated to COVID-19, but who tested positive as a secondary diagnosis, were excluded from the study data, he noted. 

"If you live in Michigan and you're not vaccinated, you need to take a look at this study, because the data that are published is from a population that's just like you," he said.

The study proves what health care providers had already observed — that vaccination protects people from severe COVID-19 disease, hospitalization and death, Bahl added.

During the study period, there were 1.29 emergency center COVID-19 visits per 100,000 persons among fully vaccinated individuals, compared with 12.88 visits per 100,000 partially vaccinated patients and 22.61 visits per 100,000 unvaccinated patients. 

Elderly patients with significant co-morbidities who required hospital-based treatment tended to suffer more severe outcomes regardless of their vaccination status, however. 

The average age of the unvaccinated people who tested positive during the study period was 52, compared with an average age of 72 for the group who were fully vaccinated — 20 years older.

"Many of these people with breakthrough infections had multiple co-morbidities," Bahl noted. "So these patients did have ICU stays, they were put on ventilators, they died at a similar rate to a similarly matched unvaccinated cohort. 

"They were a vulnerable population. Their baseline risk is exceedingly high of any bad outcome." 

Eight deaths and six intubations occurred in the fully vaccinated group, all in patients over the age of 65. In the unvaccinated group, 384 deaths occurred, with one patient as young as 21 dying in the hospital. 

Dr. Barbara Ducatman, chief medical officer of Beaumont, Royal Oak, said the study underscored the need to be very protective of elderly, vulnerable people, and to shield them from exposure to the virus. 

 "Certainly for those 65 and above, or even 60 and above, if you aren't vaccinated I would highly recommend that you consider vaccination," she said. 

"Even younger people are getting ill with this, and as we know children under 12 can still not be vaccinated, and across the country we're seeing rising hospitalizations," Ducatman added. "We can protect not only ourselves but other members of our family by getting vaccinated." 

Ducatman said Beaumont Health has administered about 375,000 doses of COVID-19 vacine through Wednesday and fully vaccinated 186,392 people. But the number of people getting vaccinated has been declining since June, she added. 

The health system has started giving a third booster shot of the Pfizer vaccine to immuno-compromised individuals. Hospital officials hope to be able to open the booster to other adults starting about Sept. 20, depending on CDC guidance. 

"The take-home message is that vaccination works," Bahl said. "It is such a powerful tool to keep you out of the emergency room, to keep you out of the hospital, to keep you at home safe.

"If you now vaccinated, and you're considering it — you're on the fence, let's say, or you're young and healthy, and you don't think you can die from it — look at my study.

"You're wrong not to at least take a look, and weigh the evidence."

Twitter: @kbouffardDN