In one of the first investigations of the real-world effectiveness of COVID-19 booster vaccines, a new study published by Beaumont Health found COVID-19 booster shots significantly reduced the death rate for hospitalized, COVID-19 patients.
Hospitalized patients who received boosters had a 45% lower mortality rate than unvaccinated, hospitalized patients, according to the study published March 17, in The Lancet Regional Health - Americas. Boosted patients also significantly lowered their chance of death when compared to fully vaccinated patients, the peer-reviewed, open-access study showed.
The researchers found:
- The highest mortality rate was 12.8% in unvaccinated, hospitalized patients;
- Vaccinated and boosted patients had a much lower mortality rate: 7.1%.
- Patients who were fully vaccinated but had not received booster shots had a 10.3% mortality rate.
“Early indications were that boosters save lives, and this real-world research shows that boosters saved hundreds of lives at Beaumont alone,” said the study’s principal investigator, Dr. Amit Bahl, director of Emergency Ultrasound for Beaumont Hospital, Royal Oak, Beaumont's Level 1 Trauma Center. He 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, Royal Oak.
The study of more than 8200 Beaumont patients hospitalized with a primary diagnosis of COVID-19 also found that boosted patients survived better than fully vaccinated patients, even when they had more comorbidities.
The boosted group:
- Was older, with a median age of 73 years old compared 70 years old in the vaccinated-only group;
- Had a higher rate of pre-existing, end-stage kidney disease (13.6% vs 6.2%);
- Was more immunocompromised (29.5% vs 17.9%).
“Boosters are even more important for those who have pre-existing conditions or are immunocompromised,” Dr. Bahl said. “As the research shows, the booster helped even older, sicker patients survive the COVID-19 virus better than unvaccinated or un-boosted patients.”
In addition, the researchers believe the timing of booster administration and the onset of infectious symptoms is important. About 30% of the vaccinated and boosted patients who died received their booster less than 12 days from the onset of COVID-19 symptoms.
“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, adding that an Israeli study found significant increase in COVID-19 antibodies in patients who were more than 12 days post-booster.
The study looked retrospectively at data of adult patients hospitalized with a primary diagnosis of COVID-19 between Aug. 12, 2021 and Jan. 20, 2022 at Beaumont's eight hospitals across southeast Michigan. The researchers looked at medical records with patients’ identifying information removed. Patients who were children, partially vaccinated or still hospitalized at the study’s conclusion on Feb. 1, 2022 were excluded, as were COVID-19 patients who were treated and released from the emergency center to recuperate at home.
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. The study authors followed current U.S. Centers for Disease Control and Prevention guidelines to classify patients’ vaccination status.
- Fully vaccinated and boosted patients had received:
- Three doses of an mRNA vaccine (Pfizer, Moderna) or
- One dose of a viral vector vaccine (Janssen) and one dose of the mRNA or
- One dose of a viral vector vaccine and two doses of the mRNA or
- Two doses of a viral vector vaccine.
- Fully vaccinated patients had received:
- Two doses of an mRNA vaccine (Pfizer, Moderna) or
- one dose of a ¬viral vector (Janssen).
- The unvaccinated patients did not have any COVID-19 vaccine in their medical record or in state vaccination databases.
“This study reinforces Beaumont's commitment to support proper vaccination and boosters for all of our patients who can be vaccinated,” said infectious diseases expert Dr. Matthew Sims, director of Infectious Disease Research for Beaumont Health. “Looking back at what helps protect patients from the COVID-19 virus will certainly help us battle this and other viruses in the future.”
The Lancet Regional Health - Americas is an open-access journal devoted to sharing research that can improve clinical practice and health qualities in the Americas. The journal is a sister publication to The Lancet, a highly regarded, independent, global medical journal dedicated to advancing the science of medicine to transform society and positively impact people’s lives.