Beaumont study shows effectiveness of COVID-19 boosters in hospitalized patients

Karen Bouffard
The Detroit News

A new study published by Beaumont Health found COVID-19 booster shots significantly reduced the death rate for hospitalized COVID-19 patients and provided more protection than the vaccine alone.

The study found that hospitalized patients who received boosters had a 45% lower mortality rate than unvaccinated, hospitalized patients. It was published March 17 in The Lancet Regional Health – Americas.

"There've been publications across the globe over the last six months that have been really powerful and robust in supporting the use of vaccination...(but) there's really very little clinical data that supports the use of boosters to this point," said Dr. Amit Bahl, director of emergency ultrasound for Beaumont Hospital, Royal Oak, and the study's lead investigator.

"What we found was that there's a definite added benefit in terms of mortality getting boosted," Bahl said Tuesday during a briefing with media about the study.

The peer-reviewed, open-access study looked at 8,200 patients who were hospitalized with a primary diagnosis of COVID-19 from August 2021 through January of this year — a time period that captured spikes in cases associated with both the delta and omicron variants, Bahl noted.

The researchers said 5.8% of hospitalized COVID-19 patients in the study were fully vaccinated and boosted, 29.2% were fully vaccinated but not boosted and 65% were unvaccinated.

They found the mortality rate was 7.1% for hospitalized patients who were vaccinated and boosted, compared to 10.3% for patients who were vaccinated but had not received a booster shot. The highest mortality rate was 12.8% for unvaccinated, hospitalized COVID-19 patients. 

Bahl conducted the study with medical student Nicholas Mielke of the Oakland University William Beaumont School of Medicine and Dr. Steven Johnson, also an emergency physician at Beaumont Hospital, Royal Oak.

Bahl noted that the boosted patients had a lower mortality rate even though the group was older and had higher rates of comorbidities.

The median age of the boosted patients was 83, compared with a median age of 70 for the vaccinated but not boosted group. Of those who were boosted, 13.6% had pre-existing end-stage kidney disease, compared with 6.2% of those who were not boosted. And 29.5% of the boosted group was immunocompromised, compared with 17.9% of the un-boosted patients.  

"Even if you were older or had a high degree of comorbidities — (meaning) your baseline risk was higher, and you were a sicker individual — you still had an added mortality benefit by getting boosted," Bahl said.

About 30% of the vaccinated and boosted patients who died received their booster less than 12 days prior to developing COVID-19 symptoms.

Bahl said that timing may be significant since an Israeli study found a significant increase in COVID-19 antibodies in patients who were more than 12 days post-booster.

“These fully vaccinated and boosted patients may not have had enough time for their body to develop the full benefit of the booster,” Dr. Bahl said.

Twitter: @kbouffardDN