Journal of Clinical Virology - Volume 82 - Supplement 1 - September 2016

72 / 152

S68 Abstracts / Journal of Clinical Virology 82S (2016) S1–S142
sion of genotyping is most likely to be largely responsible for the
mentioned change in distribution of subtypes.
Abstract no: 160
Presentation at ESCV 2016: Poster 94
Hepatitis E virus seroprevalence in East- and
West Flanders, Belgium: Comparison between
2011 and 2016
L. Cattoir ∗, E. Nys , H. Van Vlierberghe ,
A. Geerts erhelst adalko
1 Department of Clinical Chemistry, Microbiology
and Immunology, Ghent University and Hospital,
Ghent, Belgium
2 Department of Gastroenterology and Hepatology,
Ghent University and Hospital, Ghent, Belgium
Background: Hepatitis E virus (HEV) infection is increasingly
recognized as a cause of hepatitis in developed countries. There
are wide variation in HEV seroprevalence between countries and
regions. Moreover, some authors report changing seroprevalence
numbers over time. Differences in performance characteristics
between serological assays used could explain some of these find-
ings. However, significantly different seroprevalence figures are
also reported using the same assay. The objective of this study was
to evaluate the current HEV seroprevalence in East- andWest Flan-
ders, Belgiumand to assess the evolution of the seroprevalence over
time.
Materials and methods: In the setting of the Ghent University
Hospital, samples of 200 patients (100 between June 29th and July
2nd 2011 and 100 between May 9th and May 12th 2016) without
clear evidence of hepatitis nor gastroenterological problems were
randomly selected for anti-HEV IgG testing (Wantai Biological Phar-
macy, Beijing, China). The median age of the selected individuals
was 39 (range 17–82 years) and 37 (range 18–82 years) years old
in 2011 and 2016 respectively. In both groups themale/female ratio
was 1.
Results: 15/100 samples collected in 2011 and 15/100 sam-
ples collected in 2016 tested positive for anti-HEV IgG. Both study
groups (2011 and 2016) showed an increasing seroprevalence with
age. In 2011, we found a similar anti-HEV IgG seroprevalence for
men (16%; 8/50 patients) and women (14%; 7/50 patients). In the
2016 subgroup, the HEV seroprevalence seems to differ according
to sex. A higher seroprevalence (24%; 12/50 patients) was found for
men in comparisonwithwomen (6%; 3/50 patients). This difference
was statistically significant (Fisher’s exact test p = 0.22).
Conclusion: East- and West Flanders in Belgium, with HEV
seroprevalence of 15%, can be classified as region with moderate
seroprevalence. There seems to be no increasing trend over the last
5 years. The observed predominance of HEV IgG positivity in men
over women in 2016 has to be further explored.
Abstract no: 166
Presentation at ESCV 2016: Poster 95
Lyophilising have to create a stable product, is it
possible?
Rehan Minhas ∗, Jacqueline Fryer, Philip Minor,
Neil Almond, Clare Morris
Division of Virology, NIBSC, UK
Picornaviruses are notoriously difficult to lyophilise without
compromising viral integrity, however the value of producing sta-
ble hepatitis A viral reference materials in this format is paramount
to assure assay sensitivity for the detection of both contamination
of blood derived medicinal products and patient diagnosis.
NAT assays are readily available for HAV RNA detection, how-
ever in-house assays are predominant and typically have variations
in sensitivity and specificity.Without the availability of suitable ref-
erence materials it is then impossible to compare results between
laboratories or different assays. A WHO International Standard for
Hepatitis A Virus RNA NAT assays has been available since 2000
and has helped considerably in the harmonisation of these assays.
However, whilst establishing a replacement HAV IS, the stability
of lyophilised picornavirus came into question. Accelerated ther-
mal degradation samples of two replacement batches suggested
that there was a loss of potency of up to 1 log10 upon storage of
lyophilised material at +4 ◦ C over 5 years, with a second batch
showing such losses after only 10.5 months, this was in compar-
ison to the corresponding loss of potency for 1st HAV IS which was
observed to be <0.1 log10.
Stability and homogeneity over time are critical attributes of a
reference material. Stability is evaluated to provide an estimate of
the length of time for which the reference standard will remain
suitable for its intended purpose under its defined storage condi-
tions.
We have undertaken a pilot study to investigate suitable formu-
lations for minimizing loss in potency of HAV upon freeze drying
and degradation in storage at elevated temperatures using a range
of NAT assays prior to the development of the replacement HAV
RNA IS this comprised for formulations tested by three laboratories
using different assays.
In the pilot study, we collaborated with the Paul Erlich institute
and Altona Diagnostics to analyse HAV freeze dried formulations
stored at elevated temperatures in accelerated degradation studies.
The analysis indicated the formulation with Trehalose and Hepes
buffer, reduced initial loss in potency upon freeze drying and subse-
quent storage at elevated temperatures using a number of different
NAT assays. The findings from this study guided the formulation for
the replacement standard, whichwill be assessed in direct compar-
ison to a standard formulated in plasma only over a long termin a
multicenter collaborative study, involving a broader range of NAT-
based assays. Each participant will be asked to evaluate dilution
series of the candidate IS’s for HAV alongside a panel of clinical
samples.
We shall present the results of this second study to establish
whether there is improvement in the stability for HAV reference
materials using the new formulation. Two candidate formulations
one with plasma only the other with excipients, freeze dried and
liquid bulk samples will be compared using a range of assays to
assess initial loss of potency. The implications of these data and
suitability of the IS to improve the quality and comparability of
NAT based assays for HAV will be discussed.
Keywords: HAV International Standard, Freeze drying, Stability.