"Immunocompromised" is a large bucket — and not all immunocompromising conditions affect a person's ability to produce antibodies in response to COVID-19 vaccination the same way, research published June 30 in the preprint server MedRxiv suggests.
Nearly all patients with HIV, for example, produced antibodies after being vaccinated against COVID-19, while the minority of lung transplant recipients did not have antibodies after vaccination.
Between April 14 and June 14, researchers from the University of Pittsburgh Medical Center tested the blood samples from 107 healthcare workers who did not have immunocompromising conditions and from 489 immunocompromised patients who were fully vaccinated against the coronavirus.
Nearly all of the healthcare workers, 98 percent, were positive for antibodies after receiving the vaccine while patients with conditions that compromise their immune systems displayed a wide range of antibody responses.
Here is a breakdown of the antibody responses among immunocompromised participants, based on condition:
- Solid organ transplant recipients: About 37 percent produced antibodies. Of this group, lung transplant recipients fared the worst, with just 22.2 percent producing antibodies, compared to about 61 percent of liver transplant patients producing antibodies.
- Blood cancer patients: Nearly 55 percent produced antibodies.
- Solid tumor cancer: Nearly 84 percent produced antibodies.
- HIV: Nearly 95 percent produced antibodies.
"Our study highlights the urgent need to optimize and individualize COVID-19 prevention in patients with immunocompromising conditions and have other treatments—such as monoclonal antibodies—available should vaccination fail," said Ghady Haider, MD, lead study author and transplant infectious diseases physician at UPMC. "Given the CDC's recommendations permitting vaccinated people to abandon masking and social distancing in most settings, our findings also have implications for public health guidance, since nearly 4% of Americans are immunocompromised."
Researchers also found the ability of immunocompromised participants' blood to neutralize the virus correlated strongly with antibody levels measured by FDA-approved tests.
"This is important because we've seen several studies indicating that immunocompromised people are less likely to produce antibodies in response to COVID-19 vaccination," said John Mellors, MD, senior study author and chief of the division of infectious diseases at UPMC. "And we can assume this means they're less likely to be able to fight the virus, but until we were able to test for virus neutralization, that was only an assumption. Our results give us more confidence in saying that people who do not produce antibodies truly are at greater risk of COVID-19 infection and that the level of antibodies produced is a proxy for ability to neutralize the virus."
The CDC, FDA and several other groups currently recommend against routine antibody testing for the general population after vaccination, the researchers clarified, adding that immunocompromised people should continue taking pandemic precautions regardless of antibody test results.