CovOps
 Location : Ether-Sphere
Job/hobbies : Irrationality Exterminator
Humor : Über Serious
 |  Subject: Autoimmunity and No COVID Vax? It's Not All Bad News  Sat Mar 26, 2022 12:34 am | |
| Some risk but also some benefit seen with biologic therapies
Patients treated with biologic agents for immune-mediated inflammatory diseases (IMIDs), and who weren't vaccinated against COVID-19, had diminished and relatively short-lived antibody responses to infection, compared with non-IMID controls, researchers reported.
But with previous studies suggesting that biologic anti-rheumatic drugs give a level of protection against severe COVID-19 in IMID patients, their management during the pandemic remains a challenge, according to David Simon, MD, and Georg Schett, MD, both of Friedrich-Alexander University Erlangen-Nuremberg in Germany, and colleagues.
The study in Arthritis & Rheumatology compared 2,169 unvaccinated IMID patients to 1,639 healthy unvaccinated controls enrolled in an ongoing prospective project.
Among patients testing positive for SARS-CoV-2 infection, 38.7% had no antibodies against the virus in blood samples taken 2-3 months later, compared with 16.0% of infected controls, the researchers reported.
And, of those patients who did show antibodies in the first sample, nearly half had lost them when tested 9 months later, versus about 30% of controls. Moreover, all four patients using biologic drugs who were antibody-positive in the first round of tests tested negative at follow-up, Simon and colleagues wrote.
Overall, the findings did not bode well for unvaccinated patients with IMIDs such as rheumatoid arthritis and inflammatory bowel disease: diminished and more transient antibody responses, which "presents some challenges in maintaining protective immunity against the virus," the authors said.
Yet the group also highlighted a number of earlier studies suggesting that biologic cytokine inhibitors, particularly those targeting tumor necrosis factor (TNF) and members of the interleukin (IL) family, seem to blunt infection severity when the virus takes hold. For example, one 86-case series from early in the pandemic showed lower rates of hospitalization for IMID patients using biologic drugs versus other treatments.
A likely reason for such a protective effect is that biologic agents "mitigate the overshooting inflammatory response to the virus" that underlies the respiratory distress in severe cases, Simon and colleagues wrote.
Their own findings came from a program in Germany that was started in February 2020, at the dawn of the pandemic, to track IMID patients for COVID-related outcomes. Besides the 2,869 patients analyzed for the current study, the investigators also recruited a control group comprising one set of healthcare workers and another of people from the population at large.
Of the 1,639 controls, 455 were healthcare workers. Because the study covered the period before vaccines were available, none of the participants were vaccinated. About half the patient group was receiving biologic agents for their condition. In particular, the strongest relationships with the study's endpoints were for drugs in the TNF, IL-17, and IL-23 inhibitor classes.
Participants provided blood samples initially during March-June 2020 and, for those not lost to follow-up, again from December 2020-March 2021. They also completed questionnaires about overall health, medications, comorbidities, results from PCR tests for COVID-19 (if taken), and precautions they had taken to avoid infection.
Many more of the healthcare-worker controls reported positive PCR tests (16.5%) compared with the other set of controls (8.7%) or with patients (5.1%). That last figure is itself intriguing -- although Simon and colleagues didn't dwell on it, the patient group was substantially less likely to report going to risky places and less contact with infected people, and were more likely to work in a home office (both relative to the general-population controls as well as to the healthcare workers).
What the authors found more interesting was that the IMID patients taking biologic drugs were significantly less likely to have mounted detectable antibodies as of the first sampling after a positive PCR test (relative risk 0.50, 95% CI 0.34-0.73, after adjustment for risk behaviors, sampling time, age, and sex). The median time from test to sampling was about 59 days for controls and 50 days for patients, which should be long enough for a detectable antibody response to develop.
That result, along with the higher rates of antibody loss during follow-up in patients receiving biologic drugs, led Simon and colleagues to propose that these agents do, in fact, inhibit humoral immune responses after infection that could leave individuals susceptible to repeat infection. Other studies to date suggest that this does not occur with vaccination, at least not to a clinically significant extent.
How that balances with the earlier hypothesis that biologic drugs help stave off severe COVID symptoms remains to be determined, the authors added.
.https://www.medpagetoday.com/rheumatology/generalrheumatology/97846 |
|
