L'OMS et l'Unicef ont annoncé lundi dans un communiqué commun le rappel du
vaccin Shan5 sur avis d'un comité d'experts
Le vaccin Shan5 est utilisé contre la diphtérie, la coqueluche, le tétanos,
l'Haemophilus influenzae de type b, et l'hépatite B.
La société Shantha Biotechnics Ltd., contrôlée par Sanofi-Aventis SA , a
commencé à rappeler plusieurs lots de vaccins Shan5 au niveau mondial
Joint WHO-UNICEF Statement 2
26 April 2010
WHO RECOMMENDS
RECALL AND DESTRUCTION OF ALL LOTS OF SHAN5 VACCINE
AS A PRECAUTIONARY MEASURE
http://www.who.int/immunization_standards/vaccine_quality/who_unicef_joint_statement_Shan5_26apr10.pdf
The World Health Organization (WHO) recommends as a precautionary measure
the recall
and destruction of all lots of the Shantha Biotechnics (India) produced
pentavalent Shan5
(DTwP-hepatitis B-Hib) vaccine remaining in stock in countries.
The Shan5 vaccine currently held in stock in countries should not be used.
Countries have
already identified the concerned stock and are now requested to organize
transport of all
unused vaccine to central level, in coordination with WHO and UNICEF country
offices (or
the in-country entity facilitating the procurement of the vaccines if
vaccines were not
supplied through UNICEF or the Pan American Health Organization). Once
collected, the
vaccine will handed over to the named Shantha representative in the country
for
appropriate handling of return and/or destruction.
This recommendation is based on the advice of an ad hoc committee of experts
convened
on 8 April, following incidents of white sediment sticking to Shan 5 vaccine
vials that was
difficult or impossible to resuspend. There have been no reports of any side
effects from
the use of Shan5.
WHO recommends that countries continue vaccination using pentavalent vaccine
from an
alternative manufacturer or an alternative DTP-containing vaccine. Countries
should
contact WHO or UNICEF country offices (or the in-country entity facilitating
the shipments
or procurement of these vaccines) for assistance with ensuring sufficient
supply of vaccine
for continuation of immunization programmes.
Further advice and support on the necessary process for collection, return
and destruction
of the vaccine will be provided to the concerned UNICEF/WHO country offices.
Countries
supplied through other channels should coordinate directly with a Shantha
Biotechnics
representative.
Background
. During recent months, WHO received vaccine quality complaints from
Colombia,
Comoros, and Nepal regarding the presence of a white sediment sticking to
glass
vials containing Shan5 vaccine which would not re-suspend even after
vigorous
shaking.
. On 19 February, WHO recommended the temporary suspension of the
distribution
and use of specific lots of Shan5 vaccine as a precautionary measure pending
investigation.
. On 12 March, WHO recommended that the procurement and use of all lots of
the
Shan5 vaccine be temporarily suspended, after WHO received reports that
additional
lots, not included in the temporary suspension, showed a similar problem.
Countries
were advised to put any remaining vaccine into quarantine until further
notice.
. The manufacturer was asked to provide additional data and WHO undertook
independent testing in WHO-contracted laboratories.
. WHO called on an ad hoc committee of experts (from regulatory, vaccine
manufacturing and immunization programme management fields) to review
reports of
the investigation from the manufacturer, results of WHO-commissioned tests,
and the
physical appearance of the Shan5 vaccine received from the countries.
Samples of
lots of the Shan5 vaccine received during the prequalification process and
other DTP
combination vaccines were also reviewed.
. The committee concluded that the batches of the product being held in
quarantine are
unsuitable for use and should be destroyed. This recommendation was based on
several factors: the product has a different physical appearance to that
which was
prequalified; there are uncertainties about the safety and immununogenicity
profile of
the vaccine in this situation (although no reports of adverse events
following
immunization have been received); and the root cause of the change in
physical
appearance has not been established.
Shan5 vaccine quality, safety and efficacy
Although no reports of adverse events following immunization have been
received, in view of
the changed physical appearance of the affected lots, there remain
uncertainties about the
safety and immununogenicity profile of the vaccine. While the difficulty in
resuspending the
vaccine suggests that the full dose would not be given when using affected
vials, a change in
efficacy has not yet been proven..
Given this, WHO does not recommend revaccination of individuals who have
received the full
DTP-hepatitis B-Hib vaccination schedule using Shan5 at present. For
individuals who have
begun, but not completed, the schedule using Shan5, an alternative vaccine
or vaccines
should be used to complete the schedule.
Samples from affected vaccine lots are being tested in WHO-contracted
laboratories, to
check for a change in immunogenicity. Based on the results of these tests
WHO will review
its current advice not to revaccinate children who have received the full
primary series with
Shan 5. No other vaccine quality complaints besides the flocculation
described above have
been reported to WHO.
Shan5 vaccine composition and WHO prequalification
Shan5 is a combined, pentavalent vaccine containing diphtheria and tetanus
toxoids, whole
cell pertussis, recombinant DNA derived hepatitis B surface antigen, and
components of
Haemophilus influenza type b (Hib). The vaccine is absorbed onto aluminium
salts as an
adjuvant and preserved with thiomersal.
Shan5 remains on the list of WHO prequalified vaccines for the time being.
If, however, the
manufacturer is not able to identify the root cause of the quality issue and
prepare a robust
plan for corrective action within a period of two months, the product will
be removed from the
list of WHO prequalified products. The list of prequalified vaccines on the
WHO web site
currently indicates that WHO recommends recall and destruction of remaining
stocks as a
precautionary measure.
Shan5 and alternative vaccine supply
According to updated estimates, between November 2008 and February 2010,
almost 24
million doses of this vaccine were supplied to countries through UNICEF and
the Pan
American Health Organization (PAHO) Revolving Fund. The vaccine is also
procured directly
by a number of countries.
UNICEF and PAHO have been working with alternative suppliers of pentavalent
vaccines
and with the concerned countries to ensure that there is an adequate
alternative supply of
vaccines for continuation of immunization programmes.