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INFLUENZA PANDEMIC (H1N1) 2009 (03): VACCINE
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A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>
In this update:
[1] WHO update
[2] Canada Press report
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[1] WHO update
Date: Mon 13 Jul 2009
Source: World Health Organisation (WHO), Global Alert and Response,
EPR [edited]
<http://www.who.int/csr/disease/swineflu/notes/h1n1_vaccine_20090713/en/index.html>
Pandemic (H1N1) 2009 briefing note 2: WHO recommendations on pandemic
(H1N1) 2009 vaccines
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On Tue 7 Jul 2009, the Strategic Advisory Group of Experts (SAGE) on
Immunization held an extraordinary meeting in Geneva to discuss issues
and make recommendations related to vaccine for the pandemic (H1N1)
2009. SAGE reviewed the current pandemic situation, the current status
of seasonal vaccine production and potential A(H1N1) vaccine
production capacity, and considered potential options for vaccine use.
The experts identified 3 different objectives that countries could
adopt as part of their pandemic vaccination strategy:
- protect the integrity of the health-care system and the country's
critical infrastructure;
- reduce morbidity and mortality; and
- reduce transmission of the pandemic virus within communities.
Countries could use a variety of vaccine deployment strategies to
reach these objectives, but any strategy should reflect the country's
epidemiological situation, resources and ability to access vaccine, to
implement vaccination campaigns in the targeted groups, and to use
other non-vaccine mitigation measures.
Although the severity of the pandemic is currently considered to be
moderate, with most patients experiencing uncomplicated, self-limited
illness, some groups such as pregnant women and persons with asthma
and other chronic conditions such as morbid obesity [body mass index
(weight/square of height) = 40 plus. - Mod.JW] appear to be at
increased risk for severe disease and death from infection.
Since the spread of the pandemic virus is considered unstoppable,
vaccine will be needed in all countries. SAGE emphasized the
importance of striving to achieve equity among countries to access
vaccines developed in response to the pandemic (H1N1) 2009.
The following recommendations were provided to the WHO Director-General:
- All countries should immunize their health-care workers as a 1st
priority to protect the essential health infrastructure. As vaccines
available initially will not be sufficient, a step-wise approach to
vaccinate particular groups may be considered. SAGE suggested the
following groups for consideration, noting that countries need to
determine their order of priority based on country-specific
conditions: pregnant women; those aged above 6 months with one of
several chronic medical conditions; healthy young adults of 15 to 49
years of age; healthy children; healthy adults of 50 to 64 years of
age; and healthy adults of 65 years of age and above.
- Since new technologies are involved in the production of some
pandemic vaccines, which have not yet been extensively evaluated for
their safety in certain population groups, it is very important to
implement post-marketing surveillance of the highest possible quality.
In addition, rapid sharing of the results of immunogenicity and
post-marketing safety and effectiveness studies among the
international community will be essential for allowing countries to
make necessary adjustments to their vaccination policies.
- In view of the anticipated limited vaccine availability at global
level and the potential need to protect against "drifted" strains of
virus, SAGE recommended that promoting production and use of vaccines
such as those that are formulated with oil-in-water adjuvants and live
attenuated influenza vaccines is important.
- As most of the production of the seasonal vaccine for the
2009-2010 influenza season in the northern hemisphere is almost
complete and is therefore unlikely to affect production of pandemic
vaccine, SAGE did not consider that there was a need to recommend a
"switch" from seasonal to pandemic vaccine production.
WHO Director-General Dr Margaret Chan endorsed the above
recommendations on 11 Jul 2009, recognizing that they were well
adapted to the current pandemic situation. She also noted that the
recommendations will need to be changed if and when new evidence
becomes available.
SAGE was established by the WHO Director-General in 1999 as the
principal advisory group to WHO for vaccines and immunization. It
comprises 15 members who serve in their personal capacity and
represent a broad range of disciplines from around the world in fields
such as epidemiology, public health, vaccinology, paediatrics,
internal medicine, infectious diseases, immunology, drug regulation,
programme management, immunization delivery, and health-care
administration.
Additional participants in the SAGE meeting included members of the ad
hoc policy advisory working group on influenza A(H1N1) vaccine, chairs
of the regional technical advisory groups and external experts.
Observers included industry representatives and regulators who did not
take part in the recommendation process in order to avoid conflicts of
interest.
--
Communicated by:
ProMED-mail <promed@promedmail.org>
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[2] Canada Press report
Date: Sun 12 Jul 2009
Source: The Canadian Press [edited]
<http://www.google.com/hostednews/canadianpress/article/ALeqM5hJMZ2o0rf1lyVv_1ZIxwdlZOqJuQ>
Swine flu vaccine production has hit a snag, with manufacturers
reporting a disappointingly low yield when vaccines viruses are grown
in eggs. The World Health Organization [WHO] says so far the yield for
egg-based production is half or less than what manufacturers get when
they make vaccine to protect against seasonal H1N1 viruses. The lion's
share of influenza vaccine is made by companies that grow the viruses
in eggs.
New seed strains are being made in the hopes of increasing the vaccine
yield, a report by the WHO's vaccine chief, Dr. Marie-Paule Kieny,
says. But if the yield cannot be increased, it will slow the rate at
which pandemic vaccine comes out of the production pipeline, adding to
the time it takes to protect populations in countries like Canada that
have purchased vaccine. And countries that haven't pre-ordered
pandemic vaccine would face substantial delays before manufacturers
have product to sell to them.
"There's nothing to suggest it will take longer to make vaccine, if in
fact everything goes as planned. The question is: How much?" says Dr.
Michael Osterholm, director of the Center for Infectious Diseases
Research and Policy at the University of Minnesota. "There is nothing
magical about making this virus. The questions will be: How much?
When? and Where will it be available?"
The yield problem is revealed in presentations WHO staff made to last
week's special meeting of the expert panel that advises the
Geneva-based global health agency on vaccine issues. The body --
called the strategic advisory group of experts on immunization, or
SAGE -- was convened to give WHO counsel on a variety of questions
about pandemic vaccine use. Those include which groups should be given
priority when vaccine becomes available and whether the WHO should
recommend companies use adjuvants, which are boosting compounds that
could help stretch limited supplies.
Kieny, head of the WHO's initiative for vaccine research, was not
available for interview Sunday [12 Jul 2009]. The WHO is expected to
reveal details of the SAGE's deliberations and recommendations on
Monday [13 Jul 2009 [but not included in the preceding WHO press
release - Mod.CP]. But a report to the meeting by Dr. Wenqing Zhang of
the WHO's global influenza program says that vaccine manufacturers who
use so-called wild-type viruses (unmodified viruses like those now
circulating around the globe) are reporting yield rates similar to
what they get when they grow seasonal H1N1 viruses in Vero cells, a
cell culture medium. However, few manufacturers produce flu vaccine
this way.
Most make vaccine in eggs, using a reassortant or hybrid seed strain
designed to improve the chances of a good yield. These seed strains
can be made by a couple of methods, but the end result is a hybrid
with the external genes of the virus that vaccine is to protect
against and the internal genes of a virus with a proven track record
for growing well. Zhang's presentation says that of the various
reassortant vaccine viruses that have been made, the one with the
highest output still only generates about half of the yield seen with
seasonal H1N1 vaccine production.
Kieny's presentation calls the yield "less than optimal" and says
laboratories in the WHO's lab network are generating new sets of
vaccine viruses as quickly as possible. Her presentation illustrates
the impact low yield would have on availability of vaccine. Somewhere
between 850-900 million and 1.8 billion doses of pandemic vaccine are
already spoken for, she reports. The low end of the scale represents
what would be needed by countries with contracts if it is shown that
one shot will be enough to protect a person; the high end represents
what those countries would need if 2 shots per person are required. If
all manufacturers used the lowest possible effective dose, if yields
are on a par with seasonal H1N1 production and if countries only used
one dose per person, manufacturers could fill all their [advance]
purchase orders by mid-November 2009, Kieny's presentation suggests.
That best-case scenario also requires that all manufacturing capacity
remains devoted to pandemic vaccine and no portion shifts back to the
production of seasonal vaccine for next year's [2010] Southern
Hemisphere flu season. If companies don't use low doses and countries
that have pre-purchased vaccine demand 2 shots for all their citizens,
it could be mid-April [2010] before the vaccine manufacturers in
high-income countries have free capacity to devote to making vaccine
for middle and low income countries, Kieny's presentation estimates.
90 per cent of the world's flu vaccine production capacity is in the
high-income countries that use seasonal flu vaccine. A lower yielding
vaccine "would considerably push back the time lines," the
presentation warns. Assuming the yield is half that of seasonal flu
vaccine production, it would be mid-January 2010 before producers
could fill all contracts if they use a single-shot, low-dose regime,
Kieny estimates.
She suggests even with low-dose shots, a low-yield scenario would mean
manufacturers would not be able to fill all their existing contracts
until next June [2010] if the countries opt for 2 shots per person for
all their citizens.
[Byline: Helen Branswell]
--
Communicated by:
ProMED-mail Rapporteur Mary Marshall
[see also:
Influenza pandemic (H1N1) 2009 (03): official nomenclature -- to be archived
Influenza pandemic (H1N1) 2009 (02): obesity risk factor 20090711.2482
Influenza pandemic (H1N1) 2009 - Viet Nam: patient data 20090708.2450
Influenza A (H1N1) - worldwide (86): official nomenclature 20090706.2430]
....................................................cp/msp/jw
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