COVID-19 vaccines
Vaccines typically require years of research and testing before reaching the clinic, but this year researchers embarked on a global effort to develop safe and effective coronavirus vaccines in record time. Both the Pfizer/BioNTech and Moderna vaccines have only a few months of phase 3 clinical trial data, so much remains unknown about them, including their duration of effect and any long-term safety signals. In addition to excluding immunocompromised individuals, the clinical trials did not include children or pregnant women, so data are lacking for several population subgroups.
But these will not be the only vaccines available, as the pipeline is already becoming crowded. U.S. clinical trial data from a vaccine jointly being developed by Oxford-AstraZeneca, could potentially be ready, along with a request for FDA emergency use authorization, by late January 2021.
In addition, China and Russia have released vaccines, and there are currently 61 vaccines being investigated in clinical trials and at least 85 preclinical products under active investigation.
The vaccine candidates are using both conventional and novel mechanisms of action to elicit an immune response in patients. Conventional methods include attenuated inactivated (killed) virus and recombinant viral protein vaccines to develop immunity. Novel approaches include replication-deficient, adenovirus vector-based vaccines that contain the viral protein, and mRNA-based vaccines, such as the Pfizer and Moderna vaccines, that encode for a SARS-CoV-2 spike protein.
“The special vaccine concern for immunocompromised individuals is introduction of a live virus,” Dr. Stohl said. “Neither the Moderna nor Pfizer vaccines are live viruses, so there should be no special contraindication for such individuals.”
Live vaccine should be avoided in immunocompromised patients, and currently, live SARS-CoV-2 vaccines are only being developed in India and Turkey.
It is not unusual for vaccine trials to begin with cohorts that exclude participants with various health conditions, including those who are immunocompromised. These groups are generally then evaluated in phase 4 trials, or postmarketing surveillance. While the precise number of immunosuppressed adults in the United States is not known, the numbers are believed to be rising because of increased life expectancy among immunosuppressed adults as a result of advances in treatment and new and wider indications for therapies that can affect the immune system.
According to data from the 2013 National Health Interview Survey, an estimated 2.7% of U.S. adults are immunosuppressed. This population covers a broad array of health conditions and medical specialties; people living with inflammatory or autoimmune conditions, such as inflammatory rheumatic diseases (rheumatoid arthritis, axial spondyloarthritis, lupus); inflammatory bowel disease (Crohn’s disease and ulcerative colitis); psoriasis; multiple sclerosis; organ transplant recipients; patients undergoing chemotherapy; and life-long immunosuppression attributable to HIV infection.
As the vaccines begin to roll out and become available, how should clinicians advise their patients, in the absence of any clinical trial data?
Risk vs. benefit
Gilaad Kaplan, MD, MPH, a gastroenterologist and professor of medicine at the University of Calgary (Alta.), noted that the inflammatory bowel disease (IBD) community has dealt with tremendous anxiety during the pandemic because many are immunocompromised because of the medications they use to treat their disease.
“For example, many patients with IBD are on biologics like anti-TNF [tumor necrosis factor] therapies, which are also used in other immune-mediated inflammatory diseases such as rheumatoid arthritis,” he said. “Understandably, individuals with IBD on immunosuppressive medications are concerned about the risk of severe complications due to COVID-19.”
The entire IBD community, along with the world, celebrated the announcement that multiple vaccines are protective against SARS-CoV-2, he noted. “Vaccines offer the potential to reduce the spread of COVID-19, allowing society to revert back to normalcy,” Dr. Kaplan said. “Moreover, for vulnerable populations, including those who are immunocompromised, vaccines offer the potential to directly protect them from the morbidity and mortality associated with COVID-19.”
That said, even though the news of vaccines are extremely promising, some cautions must be raised regarding their use in immunocompromised populations, such as persons with IBD. “The current trials, to my knowledge, did not include immunocompromised individuals and thus, we can only extrapolate from what we know from other trials of different vaccines,” he explained. “We know from prior vaccines studies that the immune response following vaccination is less robust in those who are immunocompromised as compared to a healthy control population.”
Dr. Kaplan also pointed to recent reports of allergic reactions that have been reported in healthy individuals. “We don’t know whether side effects, like allergic reactions, may be different in unstudied populations,” he said. “Thus, the medical and scientific community should prioritize clinical studies of safety and effectiveness of COVID-19 vaccines in immunocompromised populations.”
So, what does this mean for an individual with an immune-mediated inflammatory disease like Crohn’s disease or ulcerative colitis who is immunocompromised? Dr. Kaplan explained that it is a balance between the potential harm of being infected with COVID-19 and the uncertainty of receiving a vaccine in an understudied population. For those who are highly susceptible to dying from COVID-19, such as an older adult with IBD, or someone who faces high exposure, such as a health care worker, the potential protection of the vaccine greatly outweighs the uncertainty.
“However, for individuals who are at otherwise lower risk – for example, young and able to work from home – then waiting a few extra months for postmarketing surveillance studies in immunocompromised populations may be a reasonable approach, as long as these individuals are taking great care to avoid infection,” he said.
No waiting needed
Joel M. Gelfand, MD, MSCE, professor of dermatology and epidemiology at the University of Pennsylvania, Philadelphia, feels that the newly approved vaccine should be safe for most of his patients.
Dr. Joel M. Gelfand
“Patients with psoriatic disease should get the mRNA-based COVID-19 vaccine as soon as possible based on eligibility as determined by the CDC and local public health officials,” he said. “It is not a live vaccine, and therefore patients on biologics or other immune-modulating or immune-suppressing treatment can receive it.”
However, the impact of psoriasis treatment on immune response to the mRNA-based vaccines is not known. Dr. Gelfand noted that, extrapolating from the vaccine literature, there is some evidence that methotrexate reduces response to the influenza vaccine. “However, the clinical significance of this finding is not clear,” he said. “Since the mRNA vaccine needs to be taken twice, a few weeks apart, I do not recommend interrupting or delaying treatment for psoriatic disease while undergoing vaccination for COVID-19.”
Given the reports of allergic reactions, he added that it is advisable for patients with a history of life-threatening allergic reactions such as anaphylaxis or who have been advised to carry an epinephrine autoinjector, to talk with their health care provider to determine if COVID-19 vaccination is medically appropriate.
The National Psoriasis Foundation has issued guidance on COVID-19, explained Steven R. Feldman, MD, PhD, professor of dermatology, pathology, and social sciences & health policy at Wake Forest University, Winston-Salem, N.C., who is also a member of the committee that is working on those guidelines and keeping them up to date. “We are in the process of updating the guidelines with information on COVID vaccines,” he said.
Dr. Steven R. Feldman
He agreed that there are no contraindications for psoriasis patients to receive the vaccine, regardless of whether they are on immunosuppressive treatment, even though definitive data are lacking. “Fortunately, there’s a lot of good data coming out of Italy that patients with psoriasis on biologics do not appear to be at increased risk of getting COVID or of having worse outcomes from COVID,” he said.
Patients are going to ask about the vaccines, and when counseling them, clinicians should discuss the available data, the residual uncertainty, and patients’ concerns should be considered, Dr. Feldman explained. “There may be some concern that steroids and cyclosporine would reduce the effectiveness of vaccines, but there is no concern that any of the drugs would cause increased risk from nonlive vaccines.”
He added that there is evidence that “patients on biologics who receive nonlive vaccines do develop antibody responses and are immunized.”