6 research outputs found
A comparison of viral microneutralization and haemagglutination inhibition assays as measures of seasonal inactivated influenza vaccine immunogenicity in the first year after reduced intensity conditioning, lymphocyte depleted allogeneic haematopoietic stem cell transplant
Traditionally, immune response to influenza vaccines has been measured using the haemagglutination inhibition (HAI) assay. A broader repertoire of techniques including the sensitive viral microneutralization (VMN) assay is now recommended by the European Medicines Agency (EMA). Comparing HAI and VMN, we determined immune response to a trivalent 2015–2016 seasonal inactivated influenza vaccine (SIIV) administered to 28 recipients of allogeneic haematopoietic stem cell transplant (HSCT). Vaccination was within the first-year post-transplant at a median of 78.5 (24–363) days. The proportion of patients with baseline and post-vaccination HAI titres ≥ 1:40 were 28.6% and 25% for A(H1N1)pdm09, 14.3% at both timepoints for A(H3N2), and 32.1% and 25% for B(Phuket). Pre and Post-vaccination geometric mean titres(GMT) were higher by VMN than HAI for A(H1N1)pdm09 and A(H3N2), but lower for B(Phuket)(p= 0.05) for all components. A single seroconversion to A(H1N1) was detected by ELISA-VMN. None of patient age, lymphocyte count, days from transplant to vaccination, donor type, or graft-versus-host disease (GVHD) or immunosuppressive therapy (IST) at vaccination correlated with baseline or post-vaccination titres by either assay. This absence of seroresponse to SIIV in the first-year post HSCT highlights the need for novel immunogenic vaccination formulations and schedules in this high-risk population
Sociodemographic and psychological determinants of influenza vaccine intention among recipients of autologous and allogeneic haematopoietic stem cell transplant: a cross-sectional survey of UK transplant recipients using a modified health belief model
Objectives: Studies exploring vaccination rates among
haematopoietic stem cell transplant (HSCT) recipients
have focused on physician factors that limit uptake.
Understanding the patient factors that determine
vaccination intention is crucial to delivering a successful
vaccination programme. Using a modified health belief
model (mHBM), we conducted a cross-sectional survey
with the objective of exploring the sociodemographic
and psychological factors that determined autologous
and allogeneic HSCT recipients’ intention to receive the
seasonal inactivated influenza vaccine (SIIV) during the
2015–2016 influenza season.
Setting: The setting of our study was three tertiary
level, UK National Health Service (NHS) autologous and
allogeneic HSCT centres.
Participants: Eligible patients were aged 16 years or
over and recipients of autologous or allogeneic HSCT for
any disease indication, with no absolute contraindication
to receiving the SIIV during the next influenza season,
and having not received the SIIV since transplant. 93
participants from 3 UK NHS HSCT centres completed an
anonymous study-specific questionnaire. 78.5% were
recipients of allogeneic and 21.5% autologous HSCT.
Results: 23.7% of participants expressed low intent to
receive the SIIV. Patients aged over 65 (OR 0.02, 95%CI
0.01 to 0.57, p=0.02) and those who had not received the
SIIV prior to HSCT (OR 0.04, 95% CI 0.02 to 0.56, p=0.02)
were less likely to have high intent. A multivariate logistic
regression model incorporating constructs of the mHBM
was statistically significant (p<0.001) and explained
74.7% of variation in SIIV intention. More patients felt
that a recommendation from their HSCT team than their
general practitioner would prompt them to receive the
SIIV, and this was most pronounced in those who had low
intent.
Conclusions: The mHBM may provide a useful structure
for addressing low vaccine intent among HSCT recipients
and further interventional studies are warranted. We would
encourage HSCT and general practitioners to discuss SIIV
intention as a routine part of care
Long-term survivors following autologous haematopoetic stem cell transplantation have significant defects in their humoral immunity against vaccine preventable diseases, years on from transplant
Current international guidelines recommend routinely vaccinating haematopoetic stem cell transplant (HSCT) recipients. Despite significant infection-related mortality following autologous HSCT, routine vaccination programmes (RVP) completion is poor. For recovered HSCT recipients, it is uncertain whether catch-up vaccination remains worthwhile years later.
To determine potential susceptibility to vaccine preventable infections, we measured antibody titres in 56 patients, a median of 7 years (range 0–29) following autologous HSCT, who had not completed RVP. We found that almost all participants had inadequate titres against diphtheria (98.2%) and pneumococcal infection (100%), and a significant proportion had inadequate titres against measles (34.5%). Of those subsequently vaccinated according to available guidelines, many mounted adequate serological responses.
These data suggest a pragmatic catch-up approach for autologous HSCT recipients who have not completed RVP is advisable, with universal vaccination against some pathogens (e.g. Streptococcus pneumoniae and diphtheria) and serologically-guided approaches for others (e.g. measles and varicella zoster virus)
Joint consensus statement on the vaccination of adult and paediatric haematopoietic stem cell transplant recipients: prepared on behalf of the British society of blood and marrow transplantation and cellular therapy (BSBMTCT), the Children's cancer and Leukaemia Group (CCLG), and British Infection Association (BIA)
Haematopoietic stem cell transplant (HSCT) recipients have deficiencies in their adaptive immunity against vaccine preventable diseases. National and International guidance recommends that HSCT recipients are considered ‘never vaccinated’ and offered a comprehensive course of revaccination. This position statement aims to draw upon the current evidence base and existing guidelines, and align this with national vaccine availability and licensing considerations in order to recommend a pragmatic and standardised re-vaccination schedule for adult and paediatric HSCT recipients in the UK
Survey of period variations of superhumps in su UMa-type dwarf novae
We systematically surveyed period variations of superhumps in SU UMa-type dwarf novae based on newly obtained data and past publications. In many systems, the evolution of the superhump period is found to be composed of three distinct stages: an early evolutionary stage with a longer superhump period, a middle stage with systematically varying periods, and a final stage with a shorter, stable superhump period. During the middle stage, many systems with superhump periods of less than 0.08 d show positive period derivatives. We present observational characteristics of these stages and give greatly improved statistics. Contrary to an earlier claim, we found no clear evidence for a variation of period derivatives among different superoutbursts of the same object. We present an interpretation that the lengthening of the superhump period is a result of the outward propagation of an eccentricity wave, which is limited by the radius near the tidal truncation. We interpret that late-stage superhumps are rejuvenated excitation of a 3:1 resonance when superhumps in the outer disk are effectively quenched. The general behavior of the period variation, particularly in systems with short orbital periods, appears to follow a scenario proposed in Kato, Maehara, and Monard (2008, PASJ, 60, L23). We also present an observational summary of WZ Sge-type dwarf novae. Many of them have shown long-enduring superhumps during a post-superoutburst stage having longer periods than those during the main superoutburst. The period derivatives in WZ Sge-type dwarf novae are found to be strongly correlated with the fractional superhump excess, or consequently with the mass ratio. WZ Sge-type dwarf novae with a long-lasting rebrightening or with multiple rebrightenings tend to have smaller period derivatives, and are excellent candidates for those systems around or after the period minimum of evolution of cataclysmic variables. © 2009. Astronomical Society of Japan