https://orcid.org/0000-0002-9486-9473
Dear Editor, we found that the article on “An analysis of reported cases of hemophagocytic lymphohistiocytosis (HLH) after COVID-19 vaccinationCitation1” is interesting. This systematic study looked at cases of hemophagocytic lymphohistiocytosis (HLH) reported following COVID-19 vaccination to better understand the connection and provide treatment options. The study includes 25 patients from 17 different papers. The majority of HLH cases occurred following the BNT162b2 mRNA COVID-19 vaccine, and to a lesser amount following the ChAdOx1 nCov-19 vaccine. Three patients died despite therapy owing to varied complications. Through molecular docking, the researchers also investigated the possibility of ruxolitinib, a cytokine inhibitor, for targeted HLH therapy.
The study is based exclusively on a qualitative examination of published case reports, which may have limitations in terms of reporting bias and generalizability. Furthermore, the molecular docking analysis of ruxolitinib’s therapeutic potential for HLH after COVID-19 vaccination is preliminary and does not give clear evidence of efficacy. A clinical manifestation of asymptomatic COVID-19 can occur at any time, including before, during, and after infection, after receiving the COVID-19 vaccination, or at any other time.
Specific vaccination components, such as adjuvants or viral vectors, may cause an aberrant immunological response in susceptible individuals. These components may interact with the immune system, resulting in the development of HLH. However, it is crucial to note that the temporal link between immunization and the development of HLH does not always imply a causative association. HLH can happen on its own or be induced by causes unrelated to immunization. More research is required to determine the true incidence and cause of post-vaccination HLH. COVID-19 can co-occur even when no overt symptoms are present.Citation2 Any immunological alteration impact could potentially be brought on by undiagnosed asymptomatic COVID-19. Without the necessary laboratory testing, asymptomatic sickness cannot be totally ruled out. Genetics is becoming more widely used. The immune system’s response to a vaccine may differ depending on how it responds to specific inherited features. More multicenter trials and larger sample sizes are desirable. It may be able to perform extensive epidemiological study on the connections between illness and immunization.
Future research should examine bigger sample sizes and more rigorous approaches, such as prospective cohort studies or randomized controlled trials, to enhance the findings. More study is needed to determine the precise processes underlying HLH following COVID-19 vaccination and to evaluate the therapeutic potential of ruxolitinib in vitro and in vivo. Furthermore, to ensure the safety and efficacy of immunization programs, monitoring and reporting of adverse events connected to COVID-19 vaccinations should be maintained.
Authors’ contribution
SW 50% ideas, writing, analyzing, approval
VW 50% ideas, supervision, approval
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No potential conflict of interest was reported by the author(s).
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References
- Zhang HQ, Cao BZ, Cao QT, Hun M, Cao L, Zhao MY. An analysis of reported cases of hemophagocytic lymphohistiocytosis (HLH) after COVID-19 vaccination. Hum Vaccin Immunother. 2023 Aug;19(2):2263229. doi:10.1080/21645515.2023.2263229.
- Joob B, Wiwanitkit V. Letter to the editor: Coronavirus disease 2019 (COVID-19), infectivity, and the incubation period. J Prev Med Public Health. 2020 Mar;53(2):70. doi:10.3961/jpmph.20.065.