Safety of vaccinating sibling donors with live-attenuated varicella zoster vaccine before hematopoietic stem cell transplantation

Development of a Vaccine against Human Cytomegalovirus: Advances, Barriers, and Implications for the Clinical Practice

Human cytomegalovirus (hCMV) is one of the most common causes of congenital infection in the post-rubella era, representing a major public health concern. Although most cases are asymptomatic in the neonatal period, congenital CMV (cCMV) disease can result in permanent impairment of cognitive development and represents the leading cause of non-genetic sensorineural hearing loss. Moreover, even if hCMV mostly causes asymptomatic or pauci-symptomatic infections in immunocompetent hosts, it may lead to severe and life-threatening disease in immunocompromised patients. Since immunity reduces the severity of disease, in the last years, the development of an effective and safe hCMV vaccine has been of great interest to pharmacologic researchers. Both hCMV live vaccines-e.g., live-attenuated, chimeric, viral-based-and non-living ones-subunit, RNA-based, virus-like particles, plasmid-based DNA-have been investigated. Encouraging data are emerging from clinical trials, but a hCMV vaccine has not been licensed yet. Major difficulties in the development of a satisfactory vaccine include hCMV's capacity to evade the immune response, unclear immune correlates for protection, low number of available animal models, and insufficient general awareness. Moreover, there is a need to determine which may be the best target populations for vaccine administration. The aim of the present paper is to examine the status of hCMV vaccines undergoing clinical trials and understand barriers limiting their development.

Vaccinating donors for hematopoietic cell transplantation: A systematic review and future perspectives

Allogeneic hematopoietic cell transplantation (Allo-HCT) recipients are at an increased risk of infectious complications, which is a major cause of morbidity and mortality post-transplant. Vaccination of donors is one of the strategies that has been studied to improve immune reconstitution post-transplant, however the efficacy and safety of this strategy is not well reviewed in the literature. In this systematic review we sought to evaluate the current strategies of donor vaccination along with their immunogenicity, effectiveness and safety. Utilizing strict selection criteria with defined MeSH terminology, an electronic search was conducted from the following databases: Medline, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews and Scopus. Abstracts of various professional society meetings were also screened and hand searching of various reviews and guideline articles was carried out. The full text of 52 articles were reviewed, from which 5 articles satisfied the inclusion/exclusion criteria for effectiveness and immunogenicity trials and 1 article was included for safety data. Jadad score was used to assess the quality of included studies. The results of the included studies were inconsistent, and the studies were generally of suboptimal methodological quality. Most of the included studies (n = 3) investigated the use of more than one vaccine, however not all commonly used vaccines in HCT were investigated. None of the studies reported any long-term benefits for HCT recipients of vaccinated donors. Only one study reported safety data of using vaccination in donors. Given the suboptimal quality of the studies, and questionable effectiveness, donor vaccination cannot be recommended for all. Prospective high-quality vaccine trials in HCT donors are needed.

Looking back to move forward: a twenty-year audit of herpes zoster in Asia-Pacific

Background

Herpes zoster (HZ) is a prevalent viral disease that inflicts substantial morbidity and associated healthcare and socioeconomic burdens. Current treatments are not fully effective, especially among the most vulnerable patients. Although widely recommended, vaccination against HZ is not routine; barriers in Asia-Pacific include long-standing neglect of adult immunisation and sparse local data. To address knowledge gaps, raise awareness, and disseminate best practice, we reviewed recent data and guidelines on HZ from the Asia-Pacific region.

Methods

We searched PubMed, Scopus, and World Health Organization databases for articles about HZ published from 1994 to 2014 by authors from Australia, China, Hong Kong, India, Indonesia, Japan, Korea, Malaysia, New Zealand, the Philippines, Singapore, Taiwan, Thailand, and Vietnam. We selected articles about epidemiology, burden, complications, comorbidities, management, prevention, and recommendations/guidelines. Internet searches retrieved additional HZ immunisation guidelines.

Results

From 4007 retrieved articles, we screened-out 1501 duplicates and excluded 1264 extraneous articles, leaving 1242 unique articles. We found guidelines on adult immunisation from Australia, India, Indonesia, Malaysia, New Zealand, the Philippines, South Korea, and Thailand.

HZ epidemiology in Asia-Pacific is similar to elsewhere; incidence rises with age and peaks at around 70 years – lifetime risk is approximately one-third. Average incidence of 3–10/1000 person-years is rising at around 5% per year. The principal risk factors are immunosenescence and immunosuppression. HZ almost always causes pain, and post-herpetic neuralgia is its most common complication. Half or more of hospitalised HZ patients have post-herpetic neuralgia, secondary infections, or inflammatory sequelae that are occasionally fatal. These disease burdens severely diminish patients’ quality of life and incur heavy healthcare utilisation.

Conclusions

Several countries have abundant data on HZ, but others, especially in South-East Asia, very few. However, Asia-Pacific countries generally lack data on HZ vaccine safety, efficacy and cost-effectiveness. Physicians treating HZ and its complications in Asia-Pacific face familiar challenges but, with a vast aged population, Asia bears a unique and growing burden of disease. Given the strong rationale for prevention, most adult immunisation guidelines include HZ vaccine, yet it remains underused. We urge all stakeholders to give higher priority to adult immunisation in general and HZ in particular.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2198-y) contains supplementary material, which is available to authorized users.

Clinical evaluation of safety and immunogenicity of PADRE-cytomegalovirus (CMV) and tetanus-CMV fusion peptide vaccines with or without PF03512676 adjuvant

BACKGROUND

It has been reported that cytomegalovirus (CMV) pp65-specific T cells can protect hematopoietic cell transplant (HCT) recipients from CMV complications. Two candidate CMV peptide vaccines composed of the HLA A*0201 pp65(495-503) cytotoxic CD8(+) T-cell epitope fused to 2 different universal T-helper epitopes (either the synthetic Pan DR epitope [PADRE] or a natural Tetanus sequence) were clinically evaluated for safety and ability to elicit pp65 T cells in HLA A*0201 healthy volunteers.

METHODS

Escalating doses (0.5, 2.5, 10 mg) of PADRE or Tetanus pp65(495-503) vaccines with (30 adults) or without (28 adults) PF03512676 adjuvant were administered by subcutaneous injection every 3 weeks for a total of 4 injections.

RESULTS

No serious adverse events were reported, although vaccines used in combination with PF03512676 had enhanced reactogenicity. Ex vivo responses were detected by flow cytometry exclusively in volunteers who received the vaccine coadministered with PF03512676. In addition, using a sensitive in vitro stimulation system, vaccine-elicited pp65(495-503) T cells were expanded in 30% of volunteers injected solely with the CMV peptides and in all tested subjects receiving the vaccines coinjected with PF03512676.

CONCLUSIONS

Acceptable safety profiles and vaccine-driven expansion of pp65(495-503) T cells in healthy adults support further evaluation of CMV peptide vaccines combined with PF03512676 in the HCT setting.

CLINICAL TRIALS REGISTRATION

NCT00722839.

Natural and adoptive T-cell immunity against herpes family viruses after allogeneic hematopoietic stem cell transplantation

Reactivated infections with herpes family-related cytomegalovirus, Epstein-Barr virus and varicella zoster virus are serious and sometimes life-threatening complications for patients undergoing allogeneic hematopoietic stem cell transplantation. The pathogenesis of these infections critically involves the slow and inefficient recovery of antiviral T-cell immunity after transplantation. Although efficient drugs to decrease viral load during this vulnerable period have been developed, long-term control of herpes viruses and protection from associated diseases require the sufficient reconstitution of virus-specific memory T cells. To heal the deficiency by immunotherapeutic means, numerous research groups have developed antiviral vaccines and strategies based on the adoptive transfer of virus-specific T cells. This article summarizes the substantial progress made in this field during the past two decades and gives future perspectives about challenges that need to be addressed before antigen-specific immunotherapy against herpes family viruses can be implemented in general clinical practice.

Management of HSV, VZV and EBV infections in patients with hematological malignancies and after SCT: guidelines from the Second European Conference on Infections in Leukemia

These guidelines on the management of HSV, VZV and EBV infection in patients with hematological malignancies and after SCT were prepared by the European Conference on Infections in Leukemia following a predefined methodology. A PubMed search was conducted using the appropriate key words to identify studies pertinent to management of HSV, VZV and EBV infections. References of relevant articles and abstracts from recent hematology and SCT scientific meetings were also reviewed. Prospective and retrospective studies identified from the data sources were evaluated, and all data deemed relevant were included in this analysis. The clinical and scientific background was described and discussed, and the quality of evidence and level of recommendation were graded according to the Centers for Disease Control criteria.