COVID-19 vaccines weaker in liver transplant recipients, CLD patients

Vaccines against the coronavirus disease 2019 (COVID-19) induce weaker and more transient immune responses in liver transplant recipients, those with cirrhosis, or those with chronic liver disease (CLD), according to a study presented at The Liver Meeting Digital Experience 2021 by the American Association for the Study of Liver Diseases (AASLD 2021).

These findings point to the suboptimal efficacy of COVID-19 vaccines in immunocompromised patients or those on immunosuppressive medications.

The researchers conducted a prospective analysis of 233 adult patients (mean age 63.0±11.9 years, 49 percent women), of whom 62 had undergone liver transplantation, 79 had cirrhosis, and 92 had CLD. Moderna shots were the most used type of vaccine, injected in 47 percent of patients. This was followed by Pfizer (45 percent) and Johnson & Johnson (8 percent) vaccines. [AASLD 2021, Chauhan M, et al]

A semiquantitative assay was used to assess antibody response to the spike protein. Patients were grouped into three according to titres: undetectable (≤0.4 U/mL), suboptimal (0.4–249 U/mL), and optimal (≥250 U/mL).

Sixty-six percent (n=154) of participants demonstrated optimal immune response to COVID-19 vaccines, including 75 percent (n=69) of CLD patients and 77.2 percent (n=61) of those with cirrhosis. In contrast, 26.2 percent (n=61) showed suboptimal response, including 43.5 percent of liver transplant recipients.

Notably, antibodies against the spike protein were undetectable in 17.8 percent of liver transplant recipients, 3.8 percent of cirrhosis patients, and 4.3 percent of those with CLD.

Moreover, grouping both suboptimal and undetectable immune responses, the researchers pointed out that 61.3 percent of transplant recipients showed poor vaccine response, along with 22.8 percent and 25 percent of cirrhosis and CLD patients, respectively.

Multiple logistic regression analysis confirmed that liver transplantation was a significant predictor of suboptimal/undetectable antibody response, increasing such likelihood by almost three times (odds ratio [OR], 2.71, 95 percent confidence interval [CI], 1.03–7.13; p=0.04). In contrast, using either Moderna (OR, 0.02, 95 percent CI, 0.01–0.10; p<0.0001) or Pfizer (OR, 0.06, 95 percent CI, 0.02–0.24; p=0.03) vaccines, as opposed to Johnson & Johnson, was associated with better immune responses.

Using immunosuppressive drugs also correlated with worse immune response. For instance, using one such medication increased the likelihood of undetectable/suboptimal antibody response by more than three times (OR, 3.12, 95 percent CI, 1.12–8.68; p=0.66), while taking two to three immunosuppressants aggravated this risk by nearly 15 times (OR, 14.38, 95 percent CI, 5.09–40.66; p<0.0001).

“Although clinical efficacy of COVID-19 vaccines in immunocompromised patients was unknown, many societies had recommended vaccination of this highly vulnerable patient population,” the researchers said.

To this end, the present study aimed to assess antibody responses to three prevalent vaccines in an immunocompromised population. The findings revealed that “liver transplantation, use of immunosuppressive medications, and vaccination with a single dose of Johnson & Johnson vaccine were associated with poor antibody response,” the researchers added.