Vaccines Are Less Effective at Protecting Against Severe COVID-19 in Immunocompromised Adults

Sensitive people should receive a 3-dose series of vaccines and a booster.

New real-world evidence gathered by the US Centers for Disease Control and Prevention (CDC) shows that COVID-19 vaccines are less effective in protecting against COVID-19-associated hospitalizations in people who are immunocompromised.

In general, immunocompromised individuals are at increased risk for severe COVID-19 outcomes.

“These findings indicate that while two doses of mRNA COVID-19 vaccines are beneficial for immunocompromised individuals, they are significantly less protected against serious disease than those with normal immune systems,” said lead author Peter Embí, MD, MS, Regenstrief Institute president and chief executive officer and associate dean for computer science and health services research at Indiana University School of Medicine. “Because they are less protected after a series of two doses, those who are immunocompromised should receive an extra dose and booster, take additional precautions such as masking in public, and, if they become infected, they should be treated with proven therapies.” which may protect against progression to serious disease and the need for hospitalization.”

The research team collected data from more than 89,000 hospitalizations in nine states, making this the largest study of its kind evaluating the effectiveness of COVID-19 vaccines among immunocompromised people. Data analyzes showed that mRNA vaccines (manufactured by Pfizer and Moderna) were 90 percent effective in protecting against COVID-related hospitalization in immunocompetent individuals, while they were only 77 percent effective in those with suppressed immunity due to a range of health conditions. The differences were similar between age groups. However, effectiveness varied widely between immunocompromised subgroups. For example, it was lower in organ or stem cell transplant patients and better in people with rheumatological or inflammatory conditions.

The data came from the VISION Network, a collaboration between the CDC and seven organizations that integrated medical, laboratory and vaccination data. The network was established to assess the effectiveness of COVID-19 vaccines. In addition to Regenstrief Institute, other members include Columbia University Irving Medical Center, HealthPartners, Intermountain Healthcare, Kaiser Permanente Northern California, Kaiser Permanente Northwest, and University of Colorado.

The article, “Effectiveness of Two-Dose Vaccination with mRNA COVID-19 Vaccines on COVID-19-Associated Hospital Admissions in Immunocompromised Adults – Nine States, January-September 2021,” is published in the CDC’s Morbidity and Mortality Weekly Report.

dr. Embí is the first author. Other authors of Regenstrief and IU are Shaun Grannis, MD, MS; Brian Dixon, PhD, MPA; William F. Fadel, PhD and Nimish R. Valvi, DrPH.

Other authors on the paper are Matthew E. Levy, PhD, of Westat; Allison L. Naleway, PhD, of Kaiser Permanente Northwest; Palak Patel, MBBS, of the CDC COVID-19 Response Team; Manjusha Gaglani, MBBS, of Texas A&M University; Karthik Natarajan, PhD, of Columbia University and New York Presbyterian Hospital; Kristin Dascomb, MD, PhD, of Intermountain Healthcare; Toan C. Ong, PhD, of the University of Colorado; Nicola P. Klein, MD, PhD, of Kaiser Permanente Northern California; I-Chia Liao, MPH, of Texas A&M University; Jungmi Han of Columbia University; Edward Stenehjem, MD, of Intermountain Healthcare; Margaret M. Dunne, MSc, van Westat; Ned Lewis, MPH, of Kaiser Permanente Northern California; Stephanie A. Irving, MHS, of Kaiser Permanente Northwest; Suchitra Rao, MBBS, of the University of Colorado; Charlene McEvoy, MD, of HealthPartners Institute; Catherine H. Bozio, PhD, of the CDC COVID-19 Response Team; Kempapura Murthy, MBBS, of Texas A&M University; Nancy Grisel, MPP, of Intermountain Healthcare; Duck-Hye Yang, PhD, van Westat; Kristin Goddard, MPH, of Kaiser Permanente Northern California; Anupam B. Kharbanda, MD, of Minnesota for Children; Sue Reynolds, PhD, of the CDC COVID-19 Response Team; Chandni Raiyani, MPH, of Intermountain Healthcare; Julie Arndorfer, MPH, of Intermountain Healthcare; Elizabeth A. Rowley, DrPH, van Westate; Bruce Fireman, MA, of Kaiser Permanente Northern California; Jill Ferdinands, PhD, of the CDC COVID-19 Response Team; Sarah W. Ball, ScD, van Westat; Ousseny Zerbo, PhD. From Kaiser Permanente Northern California; Eric P. Griggs, MPH, of the CDC COVID-19 Response Team; Patrick K. Mitchell, ScD, van Westate; Rachael M. Porter, MPH, of the CDC COVID-19 Response Team; Salome A. Kiduko, MPH, van Westat; Lenee Blanton, MPH, of the CDC COVID-19 Response Team; Yan Zhuang, PhD from Westat; Andrea Steffens, MPH, of the CDC COVID-19 Response Team; Sarah E. Reese, PhD, van Westat; Natalie Olson, MPH, of the CDC COVID-19 Response Team; Jeremiah Williams, MPH, of the CDC COVID-19 Response Team; Monica Dickerson, MPH, of the CDC COVID-19 Response Team; Meredith McMorrow, MD of the CDC COVID-19 Response Team; Stephanie J. Schrag, DPhil, of the CDC COVID-19 Response Team; Jennifer R. Verani, MD of the CDC COVID-19 Response Team; Alicia M. Fry, MD of the CDC COVID-19 Response Team; Eduardo Azziz-Baumgartner, MD of the CDC COVID-19 Response Team; Michelle A. Barron, MD, of the University of Colorado; Mark G. Thompson, PhD, of the CDC COVID-19 Response Team and Malini B. DeSilva, MD of HealthPartners Institute.