Immune thrombocytopenic purpura following human papillomavirus vaccination

Quadrivalent human papillomavirus vaccination in girls and the risk of autoimmune disorders: the Ontario Grade 8 HPV Vaccine Cohort Study

BACKGROUND

Despite demonstrated effectiveness in real-world settings, concerns persist regarding the safety of the quadrivalent human papillomavirus (HPV4) vaccine. We sought to assess the risk of autoimmune disorders following HPV4 vaccination among grade 8 girls eligible for Ontario's school-based HPV vaccination program.

METHODS

We undertook a population-based retrospective cohort study using Ontario's administrative health and vaccination databases from 2007 to 2013. The self-controlled case series method was used to compare the rate of a composite end point of autoimmune disorders diagnosed during days 7-60 post-vaccination ("exposed" follow-up) to that at any other time ("unexposed"). The analysis was repeated to assess the effect of a history of immune-mediated diseases and time since vaccination. We also conducted an exploratory analysis of individual autoimmune disorders. Rate ratios and 95% confidence intervals (CIs) were estimated using conditional Poisson regression, adjusted for age, seasonality, concomitant vaccinations and infections.

RESULTS

The study cohort consisted of 290 939 girls aged 12-17 years who were eligible for vaccination between 2007 and 2013. There was no significant risk for developing an autoimmune disorder following HPV4 vaccination (n = 681; rate ratio 1.12, 95% CI 0.85-1.47), and the association was unchanged by a history of immune-mediated disorders and time since vaccination. Exploratory analyses of individual autoimmune disorders found no significant risks, including for Bell palsy (n = 65; rate ratio 1.73, 95% CI 0.77-3.89), optic neuritis (n = 67; rate ratio 1.57, 95% CI 0.74-3.33) and Graves disease (n = 47; rate ratio 1.55, 95% CI 0.92-2.63).

INTERPRETATION

We did not observe an increased risk of autoimmune disorders following HPV4 vaccination among teenaged girls. These findings should reassure parents and health care providers.

Autoimmune/Inflammatory Syndrome Induced by Adjuvants and Thyroid Autoimmunity

The autoimmune/inflammatory syndrome induced by adjuvants (ASIA), presented by Shoenfeld and Agmon-Levin in 2011, is an entity that incorporates diverse autoimmune conditions induced by the exposure to various adjuvants. Adjuvants are agents that entail the capability to induce immune reactions. Adjuvants are found in many vaccines and used mainly to increase the response to vaccination in the general population. Silicone has also been reported to be able to induce diverse immune reactions. Clinical cases and series of heterogeneous autoimmune conditions including systemic sclerosis, systemic lupus erythematosus, and rheumatoid arthritis have been reported to be induced by several adjuvants. However, only a small number of cases of autoimmune thyroid disorder have been included under the umbrella of ASIA syndrome. Indeed, clinical cases of Hashimoto's thyroiditis and/or subacute thyroiditis were observed after the exposure to vaccines as well as silicone implantation. In our review, we aimed to summarize the current knowledge on ASIA syndrome presented as endocrinopathies, focusing on autoimmune thyroid disorders associated with the various adjuvants.

Immune thrombocytopenic purpura (ITP) associated with vaccinations: a review of reported cases

Immune thrombocytopenic purpura (ITP) is an autoimmune condition characterized by low platelet count with mucocutaneous and other bleedings. Clinical manifestations may range from spontaneous formation of purpura and petechiae, especially on the extremities, to epistaxis, bleeding at the gums or menorrhagia, any of which occur usually if the platelet count is below 20,000 per μl. A very low count may result in the spontaneous formation of hematomas in the mouth or on other mucous membranes. Fatal complications, including subarachnoid or intracerebral, lower gastrointestinal or other internal bleeding can arise due to an extremely low count. Vaccines may induce ITP by several mechanisms. Vaccine-associated autoimmunity may stem not only from the antigen-mediated responses but also from other constituents of the vaccine, such as yeast proteins, adjuvants, and preservatives diluents. The most likely is through virally induced molecular mimicry. The binding of pathogenic autoantibodies to platelet and megakaryocytes may cause thrombocytopenia by different mechanisms, such as opsonization, direct activation of complement, or apoptotic pathways. The autoantibodies hypothesis is not sufficient to explain all ITP cases: In the anti-platelet antibody-negative cases, a complementary mechanism based on T cell immune-mediated mechanism has been suggested. In particular, T cell subsets seem dysregulated with an increased production of pro-inflammatory cytokines, as IFN-γ and TNF, and chemokines, as CXCL10. Vaccines are one of the most striking discoveries in human history that changed dramatically life expectancy. Nonetheless, the occurrence of adverse events and autoimmune phenomena has been described following vaccination, and ITP may represent one of this.

Immune thrombocytopaenic purpura: an autoimmune cross-link between infections and vaccines

Immune thrombocytopaenic purpura (ITP) is an autoimmune systemic disease detectable by the presence of low blood platelets count (<10(5)/µl) and the production of autoantibodies against glycoproteins expressed on the platelet surface. The clinical course is often acute, and life-threatening events may occur especially in children, with 52% of paediatric patients recovering either spontaneously or after treatment. A chronic ITP evolution is observed in 64% of adults, of whom 12% will develop an overlapping autoimmune disease. Several microbial agents such as CagA-positive Helicobacter pylori or Candida albicans and a number of viruses including CMV, EBV or HIV can potentially trigger ITP through molecular mimicry. Moreover, ITP improves after treatment of the underlying infection. Similarly, vaccines such as MMR may prompt ITP (IRR 5.48, 1.61-18.64, p < 0.006). Early recognition of the underlying microbial trigger and the removal of modifiable aetiopathogenetic factors should be integrated as a complementary treatment strategy in all patients who do not readily improve with standard ITP care.

Safety of human papillomavirus vaccines: a review

Vaccination to prevent human papillomavirus (HPV)-related infection leading to cancer, particularly cervical cancer, is a major public health breakthrough. There are currently two licensed HPV vaccines, both of which contain recombinant virus-like particles of HPV types 16 and 18 (which account for approximately 70 % of cervical cancer). One vaccine also protects against HPV types 6 and 11, which cause genital warts. The safety profile of both vaccines was assessed extensively in randomised controlled clinical trials conducted prior to licensure and has been further elucidated following licensure from surveillance and specific studies in large populations. This review aims to examine current evidence regarding the safety of HPV vaccines. In summary, both vaccines are associated with relatively high rates of injection site reactions, particularly pain, but this is usually of short duration and resolves spontaneously. Systemic reactions have generally been mild and self-limited. Post vaccination syncope has occurred, but can be avoided with appropriate care. Serious vaccine-attributable adverse events, such as anaphylaxis, are rare, and although not recommended for use in pregnancy, abnormal pregnancy outcomes following inadvertent administration do not appear to be associated with vaccination. HPV vaccines are used in a three-dose schedule predominantly in adolescent females: as such case reports linking vaccination with a range of new onset chronic conditions, including autoimmune diseases, have been made. However, well-conducted population-based studies show no association between HPV vaccine and a range of such conditions. Whilst this reassuring safety profile affirms the positive risk benefit of vaccination, as HPV vaccine use expands into more diverse populations, including males, ongoing safety assessment using well-conducted studies is appropriate.

HPV vaccines and cancer prevention, science versus activism

The rationale behind current worldwide human papilloma virus (HPV) vaccination programs starts from two basic premises, 1) that HPV vaccines will prevent cervical cancers and save lives and, 2) have no risk of serious side effects. Therefore, efforts should be made to get as many pre-adolescent girls vaccinated in order to decrease the burden of cervical cancer. Careful analysis of HPV vaccine pre- and post-licensure data shows however that both of these premises are at odds with factual evidence and are largely derived from significant misinterpretation of available data.

Pandemic 2009 H1N1 virus infection associated with purpuric skin lesions: a case report

Introduction

The influenza virus infection may be severe in non-immune people. Common complications of influenza virus include upper and lower respiratory tract infections, otitis media, myocarditis, acute respiratory distress syndrome and multi-organ failure. There have been cases of vasculitis following influenza vaccination, and rash and acute purpura may occur in certain viral infections. To the best of our knowledge, there are no reports concerning cases of systemic vasculitis associated with pandemic 2009 (H₁N₁) infection.

Case presentation

A 23-year-old Caucasian woman was hospitalized at the "L. Spallanzani" National Institute for Infectious Diseases in Rome, Italy. Clinical and radiological features including laboratory findings of this case are illustrated. Notably, the patient had fever, severe abdominal pain, hematuria, arthritis, and purpuric manifestations associated with a normal platelet count. Nasopharyngeal and rectal swabs revealed pandemic 2009 (H₁N₁) virus by reverse-transcriptase-polymerase-chain-reaction assay. Routine laboratory analyses showed elevated inflammatory parameters. The autoimmune panel tests were normal. Steroid therapy associated with oseltamivir achieved an evident and rapid improvement. On day seven the patient chose to leave the hospital against medical advice.

Conclusion

Complications related to influenza infection can be life threatening, particularly in immunocompromised patients. Henoch-Schönlein purpura triggered by the novel influenza virus infection could be an attractive pathogenetic hypothesis. We have discussed both the diagnosis and the challenge of therapy protocols. Steroid therapy is part of the management of severe vasculitis. Our case suggests that steroid therapy associated with antivirals can prevent the risk of further complications such as hemorrhage and multi-organ failure during severe vasculitis, without enhancing the virulence of the influenza virus. The possible role of pandemic 2009 (H₁N₁) in the pathogenesis of hemorrhagic manifestations should be further investigated.

Review of Gardasil

Human papillomavirus (HPV) is necessary for the development of cervical cancer. Cervical cancer is the second most common cancer in women worldwide but 80% occurs in developing countries, not countries with Pap screening programs. Pap screening programs in industrialized countries have reduced the incidence of cervical cancer to 4-8/100,000 women. HPV vaccines may be a promising strategy for cervical cancer in women without access to screening programs. In industrialized countries, the benefit of HPV vaccines focuses on individual abnormal Pap test reduction not cancer prevention. The focus of this review is to cover the side effects of Gardasil in perspective with the limited population benefit cervical cancer reduction in countries with organized Pap screening programs. In addition, information about Gardasil benefits, risks and unknowns for individual patient decision making for vaccination is presented. Gardasil offers protection against CIN 2+ lesions caused by HPV 16/18 and against genital warts caused by HPV 6/11 for at least 5 years. Combining Gardasil with repeated cytology screenings may reduce the proportion of abnormal cytology screens and hence reduce the associated morbidity with the subsequent colposcopies and excisional procedures.