Rheumatic, MIS-C Patients' Parents Strongly Hesitant of COVID Vax

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NEW ORLEANS — Parents' concerns about vaccinating their children against COVID-19 remain a substantial barrier to immunizing children against the disease, whether those children have chronic rheumatologic conditions or a history of multisystem inflammatory syndrome in children (MIS-C), according to two studies presented at the Pediatric Rheumatology Symposium.

Parents of children who developed MIS-C after a SARS-CoV-2 infection were particularly hesitant to vaccinate, despite strong encouragement from healthcare professionals at Baylor College of Medicine, said the presenter of one of the studies.

"Unfortunately, it remains unclear who is susceptible and what the mechanisms are" when it comes to for MIS-C, Mariana Sanchez Villa, MS, a research coordinator at Baylor, told attendees. "Because of this, there is much hesitancy to vaccinate children with a history of MIS-C against COVID-19 out of a fear that hyperinflammation may occur."

Sanchez Villa reported findings on the vaccination rate among patients who had been hospitalized with MIS-C. The researchers included all 295 patients who presented at the hospital with MIS-C between May 2020 and October 2022. Overall, 5% of these patients had been vaccinated against COVID-19 before they were diagnosed with MIS-C. When all these patients and their families came to outpatient follow-up appointments after discharge, the subspecialist clinicians recommended the children receive the COVID-19 vaccine 3 months after discharge. The researchers then reviewed the patients' charts to see who did and did not receive the vaccine, which they confirmed through the state's immunization registry.

Among the 295 patients with MIS-C, one died, and 99 (34%) received at least one COVID-19 vaccine dose after their diagnosis, including 7 of the 15 who had also been vaccinated prior to their MIS-C diagnosis. Just over half of the vaccinated patients (58%) were male. They received their vaccine an average 8.8 months after their hospitalization, when they were an average 10 years old, and all but one of the vaccine doses they received were the Pfizer/BioNTech mRNA vaccine.

Only 9 of the 99 vaccinated patients are fully vaccinated, defined as receiving the primary series plus the recommended boosters. Of the other patients, 13 received only one dose of the vaccine, 60 received two doses, and 17 received at least three doses of the primary series doses but no bivalent boosters. Over a subsequent average 11 months of follow-up, none of the vaccinated patients returned to the hospital with a recurrence of MIS-C or any other hyperinflammatory condition. The seven patients who had been vaccinated both before and after their MIS-C diagnosis have also not had any recurrence of a hyperinflammatory condition.

"SARS-CoV-2 vaccination is well-tolerated by children with a history of MIS-C," the researchers concluded. Sanchez Villa referenced two other studies, in The Pediatric Infectious Disease Journal and in JAMA Network Open, with similar findings on the safety of COVID-19 vaccination in patients who have had MIS-C. "This is reassuring as SARS-CoV-2 becomes endemic and annual vaccination against SARS-CoV-2 is considered."

Dilan Dissanayake, MD, PhD, a rheumatologist at The Hospital for Sick Children in Toronto, Canada, who attended the presentation, told Medscape Medical News that data increasingly show a "synergistic protective effect" from COVID-19 infection and vaccination. That is, "having COVID or having MIS-C once doesn't necessarily preclude you from having it again," thereby supporting the importance of vaccination after an MIS-C diagnosis. In talking to parents about vaccinating, he has found it most helpful for them to hear about rheumatologists' experience regarding COVID-19 vaccination.

"Particularly as the pandemic went on, being able to comfortably say that we have this large patient group, as well as collaborators across the world who have been monitoring for any safety issues, and that all the data has been reassuring" has been most useful for parents to hear, Dissanayake said.

The other study, led by Beth Rutstein, MD, MSCE, an attending rheumatologist at Children's Hospital of Philadelphia, focused on the population of pediatric rheumatology patients by surveying pediatric rheumatologists who were members of the Childhood Arthritis and Rheumatology Research Alliance (CARRA). The survey, conducted during from March to May 2022, included questions about the rheumatologists' COVID-19 vaccination practices as well as perceptions of the vaccine by the parents of their patients.

The 219 respondents included 74% pediatric rheumatologists and 21% fellows. Nearly all the respondents (98%) believed that any disease flares after COVID-19 vaccination would be mild and/or rare, and nearly all (98%) recommend their patients be vaccinated against COVID-19.

The primary finding from the study was that "we [rheumatologists] have different concerns from the families," co-author and presenter Vidya Sivaraman, MD, a pediatric rheumatologist at Nationwide Children's Hospital and Ohio State University in Columbus, Ohio, told Medscape Medical News. "We're more worried about the efficacy of the vaccine on immunosuppressive medications," such as rituximab, which depletes B cells, Sivaraman said, but concerns about the vaccine's immunogenicity or efficacy were very low among parents.

Just over half the clinicians surveyed (59%) were concerned about how effective the vaccine would be for their patients, especially those receiving immunosuppressive therapy. Healthcare professionals were most concerned about patients on rituximab — all clinicians reported concerns about the vaccine's effectiveness in these patients — followed by patients taking systemic corticosteroids (86%), mycophenolate mofetil (59%), and Janus kinase inhibitors (46%).

Most clinicians (88%) reported that they had temporarily modified a patient's immunosuppressive therapy to allow for vaccination, following guidelines by the American College of Rheumatology. Aside from a small proportion of healthcare professionals who checked patients' post-vaccination serology primarily for research purposes, most clinicians (82%) did not collect this serology.

In regard to adverse events, the concern cited most often by respondents was myocarditis (76%), followed by development of new autoimmune conditions (29%) and thrombosis (22%), but the clinicians ranked these adverse events as low risk.

Meanwhile, the top three concerns about vaccination among parents, as reported to physicians, were worries about side effects, lack of long-term safety data on the vaccine, and misinformation they had heard, such as anxiety about changes to their child's genetics or vaccination causing a COVID-19 infection. "They're seeing things on social media from other parents [saying that COVID-19 vaccines are] going to affect their fertility, so they don't want their daughters to get it," Sivaraman said as another example of commonly cited misinformation.

Nearly half of the respondents (47%) said more than half of their families had concerns about side effects and the lack of data on long-term outcomes after vaccination. Only 8.5% of physicians said that fewer than 10% of their families were anxious about side effects. In addition, 39% of physicians said more than half of their families had concerns about misinformation they had heard, and only 16% of physicians had heard about misinformation concerns from fewer than 10% of their patients.

Other concerns cited by parents included their child's disease flaring; lack of data on how well the vaccine would stimulate their child's immune system; their child having already had COVID-19; and not believing COVID-19 was a major health risk to their child. Nearly every respondent (98%) said they had parents who turned down COVID-19 vaccination, and a majority (75%) reported that more than 10% of their patients had parents who were hesitant about COVID-19 vaccination.

No external funding was noted for either study. Sanchez Villa had no relevant financial relationships, but two abstract co-authors reported financial relationships with Pfizer and Moderna, and one reported a financial relationship with Novartis. Rutstein, Sivaraman, and Dissanayake had no relevant financial relationships.

Pediatric Rheumatology Symposium: Abstract 055. COVID-19 Vaccination in Children with Rheumatic Diseases: Results of a CARRA-wide Survey. Presented March 30, 2023.

Pediatric Rheumatology Symposium: Abstract 035. SARS-CoV-2 Vaccination of Children with a History of Multisystem Inflammatory Syndrome. Presented April 1, 2023.

Tara Haelle is a health/science journalist based in Dallas. Follow her at @tarahaelle