CDC analysis confirms COVID-19 danger for the immunocompromised

A new analysis by the U.S. Centers for Disease Control and Prevention (CDC) confirms that COVID-19 has been particularly dangerous to those with compromised immune systems. The CDC estimates that 2.7% of the U.S. adult population is immunocompromised due to either primary immunodeficiency or secondary immunodeficiency. But, 12.2% of the more than 22,000 COVID-19 patients hospitalized from March 1, 2020 - February 28, 2022, included in the new analysis were immunocompromised. That’s a more than four-fold overrepresentation.

Out of the patients included in the analysis, the CDC looked at how immunocompromised status affected the odds of a hospitalized COVID-19 patient ending up in an intensive care unit (ICU) or dying in the hospital. Not only were immunocompromised individuals overrepresented in the sample to start, but they were also more likely to be admitted to the ICU and more likely to die in the hospital compared to non-immunocompromised patients. This risk difference persisted even when the two groups were controlled for demographic and clinical characteristics.

As other analyses have found, not all immunocompromising conditions conveyed the same COVID-19 risk. Those with multiple myeloma, solid organ transplant, low CD4 counts (primarily due to AIDS), and immunosuppressive therapy were at the highest risk of ICU admission or death once admitted to the hospital compared to those without these conditions (regardless of immunocompromised status). In a glimmer of good news, those with immunoglobulin deficiency were at lower risk of ICU admission or death once hospitalized compared to all others in the analysis. Patients with other primary immunodeficiencies were either represented in low numbers (i.e., complement deficiency) or were not separated into their own category (i.e., it’s possible the hematopoietic stem cell transplant category contained individuals with treated PI). 

The new analysis also looked at vaccination status over the period of March 1, 2021 - February 28, 2022, in both immunocompromised and non-immunocompromised patients. Researchers found that non-immunocompromised patients hospitalized with COVID-19 who were vaccinated were less likely to be admitted to the ICU or to die in the hospital. However, for immunocompromised patients hospitalized with COVID-19, vaccination status made no difference; unvaccinated and vaccinated immunocompromised individuals were just as likely to be admitted to the ICU or to die once in the hospital. For immunocompromised patients, the value of COVID-19 vaccination seems to be primarily in preventing hospitalization in the first place.

It is important to note that the definition of “vaccinated” in this analysis was the completion of a two-shot primary series for the Moderna or Pfizer-BioNTech vaccines and one dose of the J&J/Janssen vaccine, even in the immunocompromised group. However, starting in fall 2021, the CDC has updated its vaccine recommendations for moderately to severely immunocompromised individuals several times to include additional primary and booster doses of vaccine. This analysis did not explore whether those additional vaccine doses change the risk of ICU admission or death for immunocompromised individuals admitted for COVID-19.

Overall, this study reinforces the need for multiple layers of protection against COVID-19 for people who are immunocompromised.