KIRKLAND, QC, Dec. 7, 2016 /CNW Telbec/ - Merck (NYSE:
MRK), known as MSD outside Canada
and the United States, today
announced new data from an ongoing observational effectiveness
study of single dose ZOSTAVAX® II (zoster vaccine
live, attenuated [Oka/Merck],
refrigerator-stable) being conducted by the Kaiser Permanente
Vaccine Study Center (KPVSC) and sponsored by Merck. The
study is slated to continue until 2024. The primary endpoint of the
study is evaluating vaccine effectiveness and duration of
protection against herpes zoster (also known as shingles). The
secondary endpoint of the study is evaluating the effectiveness of
the vaccine against postherpetic neuralgia (PHN), a chronic
neuropathic pain complication of shingles.1 These
data were the topic of a poster presentation made at the annual
meeting of the Canadian Immunization Conference in Ottawa, Canada.
Results for the primary endpoint of the study analyzing
effectiveness of a single dose of ZOSTAVAX II in adults 50 years of
age and older in preventing shingles were presented at the ID Week
2015 conference. These data showed that vaccine effectiveness of
ZOSTAVAX II against shingles was greater than 60 percent in all age
groups in the first year after vaccination (65, 71, 65, and 64
percent in individuals vaccinated at 50-59, 60-69, 70-79 and ≥80
years of age, respectively); vaccine effectiveness decreased in all
age groups in the second year post vaccination to an average of 47
percent across all age groups, and then decreased slowly to an
average of 32 percent across all age groups in the eighth year
following vaccination. The average 5-year vaccine effectiveness of
a single dose of ZOSTAVAX II against shingles over the first 5
years following routine vaccination was between 44 and 49 percent
among people vaccinated when 60 years of age or older (60-69, 70-79
and ≥80 years of age).
As for the secondary endpoint, the data showed that ZOSTAVAX II
had a 68.7 percent (95 percent confidence interval,
64.6-72.3) overall effectiveness against PHN in the study. This
overall effectiveness was calculated across all study individuals
vaccinated at 50 years of age or older between 2007 and 2014,
irrespective of their follow-up time up to 31 December 2014.
In the poster presented today, which included close to 49,000
shingles cases occurring between January
2007 and December 2014, the
overall 68.7 percent effectiveness of ZOSTAVAX II against PHN was
estimated by comparing, over time, the risk of PHN in vaccinated
individuals with the risk in otherwise similar individuals who were
unvaccinated at that time. Vaccine effectiveness against PHN by age
at vaccination and by year since vaccination was estimated using
Cox regression model adjusted for sex, year of birth,
race/ethnicity, and several time-varying variables, including
healthcare use, comorbid conditions and immune-compromise status.
In the first year following vaccination, vaccine effectiveness
against PHN was 82.4 percent for all ages combined. Vaccine
effectiveness against PHN decreased to 66.1 percent in the second
year for all ages combined, and then remained relatively stable
through year 7, although numbers of PHN cases became small beyond 6
years following vaccination. The vaccine effectiveness over the
entire study period, by age at vaccination, ranged approximately
from 60 to 70 percent across the age groups evaluated; (it was 63,
71, 70 and 62 percent in individuals vaccinated at 50-59, 60-69,
70-79 and ≥80 years of age, respectively).
For each age group at vaccination, an average five-year vaccine
effectiveness over the first five years following vaccination was
also calculated as an average of the first five yearly vaccine
effectiveness estimates from the Cox model. In the 2007-2014 study
period, the average five-year vaccine effectiveness against PHN was
61 percent (95% confidence interval, 47-71 percent), 69 and 72
percent among those vaccinated at 80 years of age or older, 70-79
and 60-69 years of age, respectively.
"In this observational effectiveness study, ZOSTAVAX II showed
vaccine effectiveness against shingles. The data also
demonstrated effectiveness against postherpetic neuralgia in all
age groups studied, and this continued for at least five years
after vaccination, in those vaccinated at 60 years of age or
older," said Eddy Bresnitz MD, CM,
Executive Director, Global Health and Medical Affairs, Merck
Vaccines. "These effectiveness data underscore the benefit of the
vaccine in a real world setting".
______________________________
1 Postherpetic neuralgia (PHN), the most common
complication of herpes zoster, is pain persisting in the area of
the rash after rash resolution. The duration of pain used to define
PHN varies, ranging from any duration to more than 90 days after
rash onset or resolution. PHN can last for weeks, months or even
years. A person's risk of having PHN after herpes zoster increases
with age. Older adults are also more likely to have longer lasting
and more severe pain.
About the Study
The study is being conducted at
Kaiser Permanente Northern California (KPNC) as an open cohort that
KPNC members enter when they become age-eligible for ZOSTAVAX II.
From January 2007 to
December 2014, over 1.3 million study
subjects 50 years of age and older, including close to 392,000 who
received one dose of ZOSTAVAX II, contributed approximately 5.8
million person-years of follow-up and experienced approximately
49,000 shingles episodes and 3,538 PHN episodes. This is the
largest observational effectiveness study of ZOSTAVAX II conducted
to date.
Cases of shingles were identified using an algorithm based on
information on zoster diagnosis and treatment from the study
databases, after confirming the high positive predictive value
(ability to accurately identify zoster cases) of the algorithm of
98% during the study pilot phase. Cases of PHN were identified
using an algorithm requiring a PHN diagnosis for healthcare contact
and/or treatment between 90 days and a year after the first zoster
diagnosis. One subcategory of PHN cases, representing 1,551 (44%)
of the 3,538 potential PHN cases identified by the algorithm, were
accepted without further chart review based on a high positive
predictive value of 96% in the study pilot phase. The other 1,987
(56%) potential PHN cases identified by the algorithm were all
chart reviewed to confirm them as PHN cases (89% confirmation rate,
resulting in an additional 1,765 cases). In this analysis, the
evaluation of vaccine effectiveness against HZ and PHN was based on
a comparison of the risk of HZ (or PHN) in vaccinated individuals
with that in a reference group of individuals unvaccinated at that
time but otherwise similar. Specifically, VE was estimated by age
at vaccination (50-59, 60-69, 70-79 and ≥80 years of age groups)
and by year since vaccination, using Cox proportional hazards
regression models with calendar time as the timeline, stratified by
birth year, and adjusted for sex, race/ethnicity, and several
time-varying variables, including healthcare use, comorbid
conditions and immune-compromise status at the time of risk.
In the study, PHN cases were identified based on PHN diagnosis
codes between 90 days and a year following shingles onset and
validated by chart review.
About ZOSTAVAX II
ZOSTAVAX II (zoster vaccine live,
attenuated [Oka/Merck],
refrigerator-stable) is a live attenuated virus vaccine (a
lyophilized preparation of the Oka/Merck strain of varicella-zoster virus).
ZOSTAVAX II is indicated for the prevention of herpes zoster
(shingles). ZOSTAVAX II is indicated for immunization of
individuals 50 years of age or older. ZOSTAVAX II is not a
treatment for zoster or PHN. If an individual develops herpes
zoster despite vaccination, active current standard of care
treatment for herpes zoster should be considered.
Zostavax II is administered as a single dose, subcutaneously,
preferably into the upper arm - deltoid region. ZOSTAVAX II is
currently the only available preventative means against
shingles.
To consult the full Canadian product monograph for complete
prescribing information and contraindications, warnings,
precautions, adverse reactions, interactions, dosing, and
conditions of clinical use, please click here
About Herpes Zoster
Shingles (also known as herpes
zoster) is a common and potentially debilitating disease caused by
the reactivation of the chickenpox (varicella virus) that most
people host in the nervous system since childhood. For reasons that
still remain unknown, the virus can become active again in the form
of shingles.
The vaccine works by boosting natural immunity to act
specifically against the varicella-zoster virus. About 90% of
Canadians have had chickenpox1, and it is estimated
that nearly 1 out of 3 people will develop shingles in their
lifetime2. The risk of getting shingles increases after
the age of 50.3
______________________________
1.
Immunize Canada, 2014. Herpes
Zoster (Shingles). Available online:
http://www.immunize.ca/en/diseases-vaccines/herpeszoster.aspx
(Accessed November 2015)
2. CPS, 2010. The Canadian Pain Society supports the
NACI recommendations on shingles vaccination. Available online:
http://www.newswire.ca/news-releases/the-canadian-pain-society-supports-the-naci-recommendations-on-shinglesvaccination-539273491.html
(Accessed November 2015)
3. PHAC, 2013. Fact Sheet – Shingles (Herpes Zoster).
Available online:
http://www.phac-aspc.gc.ca/id-mi/shingles-zona-fs-eng.php (Accessed
November 2015)
About Merck in Canada
For 125 years, Merck has been a
global healthcare leader working to help the world be well. Merck
is known as MSD outside Canada and
the United States. Through our
prescription medicines, vaccines, biologic therapies, and animal
health products, we work with customers and operate in more than
140 countries to deliver innovative health solutions. We also
demonstrate our commitment to increasing access to healthcare
through far-reaching policies, programs and partnerships. For more
information about our operations in Canada, visit www.merck.ca and connect with us
on YouTube.
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SOURCE Merck Canada Inc.