PDSA E-News: December 28, 2022

COVID-19 Vaccination in Children and Young Adults with Pre-Existing ITP: Data from The ITP Natural History Study Registry

Child in doctor's office after vaccineThis study is one of the first to report on the experiences of children (under 18 years of age) and young adults (18-21 years) with COVID-19 disease and vaccinations. Due to the small sample size of only 30 participants, this study serves as a preliminary report from our ITP Natural History Study Registry (patient reported registry). Data was collected from the COVID-19 & ITP survey within the registry. As of June 2022, 21 parents of children with pre-existing ITP and nine young adults with pre-existing ITP had completed the survey.

Viral disease: 11 participants were diagnosed with COVID-19 disease. Of these, five answered the survey question about their platelet response after contracting SARS-CoV-2. No platelet count decreases were reported, and there were no reports of bleeding during or after infection. Most patients who reported a platelet count change indicated their levels returned to their usual baseline within one month. There were also no hospitalizations or deaths reported.

Six of the participants who reported that they tested positive had received a thrombopoietin receptor agonist treatment for their ITP within the last six months. However, only one of these participants had also received an immunosuppressant (which included a corticosteroid and mycophenolate mofetil).

Vaccination: 24 of the 30 participants reported they had received at least one COVID-19 vaccine dose, and 20 of the 30 participants reported they had received at least two standard COVID-19 vaccine doses. A decrease in platelet counts was reported following the first dose in 23% and in 35% following the second dose. A return to pre-vaccine baseline occurred within a month in most participants. Of interest, 80% of children and young adults who reported they experienced a decrease in platelet count following dose one of the COVID-19 vaccine series also reported a platelet count decrease with dose two. When participants were asked whether they had ever experienced a decrease in platelet count following a non-COVID-19-related vaccine (such as a flu vaccine or MMR), among the six who reported they had, there were no reports of a platelet count decrease following either of the two doses of COVID-19 vaccine. Thus, having a drop in the platelet count in past from a non-COVID-related vaccine did not predict a fall in platelet count in response to COVID-19 vaccinations.



Comments from PDSA Medical Advisors

While these results are preliminary and lack specific data on actual platelet counts, they only represent a small cohort of young ITP patients. However, these results should further reduce vaccine hesitancy among pediatric and young adult ITP patients and their caregivers and encourage more young adults and parents of children with ITP to be vaccinated (including with boosters).

The bottom line for children (as well as adults) with ITP in regard to SARS-CoV-2 vaccination is:
A) a substantial platelet decrease to very low levels is very unlikely
B) if the count does fall, any degree of serious bleeding as a result is very unlikely
C) things do not get worse with subsequent vaccinations
D) if treatment is needed for a low platelet count after vaccination, it almost always works
E) the platelet count returns to what it was before vaccination almost all the time and usually does so quickly (e.g., within a month)
F) the decrease in platelet count from SARS-CoV-2 infection itself is the same or worse than any decrease following vaccination

IVIG Use and The Risk of Contracting SARS-CoV-2 in Patients with ITP: Data from The ITP Natural History Study Registry

Woman putting on maskIVIG is a common first-line therapy in the treatment of ITP. It is unclear whether IVIG reduces the risk of contracting COVID-19 disease. A reduced risk might be due to potential neutralizing antibodies against the virus in plasma donated from recovered COVID-19 patients used in the production of IVIG. This study explored whether ITP patients receiving IVIG within the last six months were less likely to test positive for COVID-19.

Data was collected from the COVID-19 & ITP survey within the registry between February 2021 – June 2022. Only participants who answered that they tested positive for COVID-19 and reported their treatments (if any) within the last six months were included. A total of 602 participants were included in the study. The participants were then stratified into three age group categories: pediatric (under 21 years), adult (22-64 years), and senior (65+ years).

Pediatric group: There were 33 pediatric participants; 18 had received at least one treatment for ITP and 11 participants had reported having tested positive for COVID-19. None of the pediatric participants reported using IVIG within the last six months. Of the 22 who reported they never tested positive for COVID-19, two had used IVIG recently.

Adult group: There were 473 adult participants; 217 had been treated with at least one ITP therapy and 95 had reported they had tested positive for COVID-19. Eleven received IVIG alone or in combination with other therapies. Among those who reported they never tested positive for COVID-19, 36 had used IVIG recently.

Senior group: There were 96 senior participants; 56 reported receiving at least one ITP treatment and seven reported they tested positive for COVID-19, one of whom reported using IVIG recently. Of those who reported they didn’t test positive, nine used IVIG recently.

There were more pediatric participants who tested positive than in the adult and senior groups combined. None of the 11 positive pediatric participants reported recent exposure to IVIG and only 12/113 (adults + seniors testing positive). When comparing positive COVID-19 cases among these with recent and no recent exposure to IVIG, there was no difference regarding IVIG use within all three age groups. This finding indicates receipt of IVIG within the past six months did not reduce the risk of contracting COVID-19 disease.



Comments from PDSA Medical Advisors

This study has several limitations. For one, the frequency and dosage of IVIG that each participant received were not stated. Second, the presence or absence of neutralizing COVID-19 antibodies within the IVIG products administered was not confirmed; of note, these have been found in lots of IVIG produced with plasma from 2022 on. Third, it is also unknown if COVID-19 antibodies, if present, were protective against the current strains of COVID-19 in the participants community given the continuing mutation in the virus and the loss of effectiveness of many of the monoclonal antibodies that previously had worked very well. Overall, the study suggests that patients cannot rely upon receipt of IVIG to protect against COVID-19 infection. This reinforces the need both for vaccination and also avoiding potential exposures to individuals at risk of transmitting the disease.



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