CDC: Latest COVID Vax Cuts Hospitalization Risk in Immunocompromised People

For adults who are immunocompromised, the updated 2023-2024 COVID-19 vaccine reduced risk of hospitalization compared with not getting the shot, according to CDC data.

Vaccine effectiveness against hospitalization was 38% in the first 7 to 59 days after receipt of the updated monovalent XBB.1.5 COVID vaccine, and 34% in the 60 to 119 days after receipt, reported Ruth Link-Gelles, PhD, of the CDC's National Center for Immunization and Respiratory Diseases, and colleagues in the Morbidity and Mortality Weekly Report.

However, despite the positive effect, only 18% of people in this high-risk population had received the updated COVID vaccine, "representing a missed opportunity to prevent severe COVID-19," the authors wrote.

Camille Kotton, MD, an infectious diseases specialist at Massachusetts General Hospital in Boston, told MedPage Today, "I am very disappointed ... that only 18% of immunocompromised patients took the opportunity to protect themselves against COVID-19. We need better messaging from the CDC and medical organizations for people to update their vaccines."

Previous CDC data found that among people who aren't immunocompromised, the updated vaccine was about 50% effective in preventing severe disease. Lower vaccine effectiveness in people who are moderately to severely immunocompromised comes as no surprise, since they are likely to have a decreased immune response to vaccination, the authors wrote.

The CDC recommends that people with moderate to severe immunocompromise should get an updated 2023-2024 COVID vaccine and can receive additional doses 2 or more months after the last vaccine dose to prevent severe illness. However, several experts who treat people in this population recently told MedPage Today that they generally recommend a COVID shot about every 6 months.

"We see significant differences in people who are vaccinated versus not. I am still strongly recommending that my patients stay up-to-date on vaccines," Kotton emphasized.

Aside from vaccination, another option that is now available for preventing COVID in people with moderate or severe immunocompromise is pemivibart (Pemgarda), a monoclonal antibody that recently received an emergency use authorization (EUA) from the FDA. This represents a welcome advance, because after the FDA withdrew the EUA for the monoclonal antibody tixagevimab-cilgavimab (Evusheld) in January 2023, people with moderate or severe immune compromise have had to rely on COVID vaccines, masking, improved ventilation, and maintaining distance in crowded areas to avoid infection and severe disease.

In the current analysis, Link-Gelles and team examined data from the CDC's VISION Vaccine Effectiveness Network to evaluate the effectiveness of the updated COVID vaccines in preventing hospitalization among adults with immunocompromise. Data on COVID-associated hospitalizations were analyzed across six sites from September 2023 to February 2024. Among 14,586 immunocompromised patients who were hospitalized for COVID-like illness, 1,392 case patients and 13,194 control patients were included.

Case patients were people who received a positive molecular SARS-CoV-2 test result and a negative, indeterminate, or unknown test result for respiratory syncytial virus and influenza. Control patients were those who had a negative molecular SARS-CoV-2 test result and a negative or unknown influenza test result.

Overall, 66% of adults in the study were 65 and older, and 72% of those hospitalized with COVID were in this age group. The study population was primarily white (69%), and 51% were women. Among case patients, 14% had received a dose of the updated COVID vaccine versus 18% of control patients.

The most common types of immunocompromising conditions were solid organ malignancy (36% of case patients and 43% of control patients), and other immune conditions or immunodeficiency (38% and 35%). Rheumatologic or inflammatory disorders were also common (30% of case patients and 25% of control patients). In addition to having an immunocompromising condition, the majority had two or more comorbidities.

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