POST 00558E : COLOR OF VVMs 15 April 2003
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mit Kartoglu (mailto:[log in to unmask]) from WHO reports problems with the
interpretation of VVM colors and announces a new WHO publication on VVM
(link below). Two attachments illustrate correct VVM colors and interpretation.
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SNOW WHITE AND VACCINE VIAL MONITORS
Recently, there has been an increased number of complaints regarding the
square color of the vaccine vial monitors (VVM). Some complaints came from
stores where VVMs attached to locally produced OPV were reported to have
been exposed to heat. In one incident, two international OPV shipments were
claimed to have 2nd stage VVMs. During the investigation of the latter
case, we have found out that two other countries that received the same lot
also noted that the VVM on arrival was at stage two.
Interestingly in almost all cases, staff was referring to VVM square as
"not white".
We would like to take this opportunity to underline once again how to read
a VVM.
WHO confirms that the starting color of the VVM square is NEVER snow white
even when stored at minus 20oC or below. The color of the VVM square may
have a blue tint which should never be confused with or taken as a
beginning of stage 2. Although in many documents and manufacturers' product
inserts 4 stages are described in VVM appearance, VVM in principle should
not be read in stages. It is important to know that a VVM never jumps from
Stage 1 to Stage 2, this transition (darkening of the VVM square) occurs
over a period of time depending on the temperature it is exposed. The
decision to receive or use the vaccine should be based on the lightness of
the VVM square with reference to the outer circle.
VVM also comes in slight different hues from batch to batch (bluish to
bluish gray). However, the interpretation of the VVM remains the same
regardless of slight changes in hue.
We would like to confirm that in none of the cases VVM was found to be
faulty. The issue was always the wrong interpretation of VVM. In one case
the country wanted to reject the two shipments claiming that the VVM was at
stage 2. WHO has asked the country to send back claimed samples. In the
meantime, WHO also asked the vaccine manufacturer to send the retained
vials sample, and the VVM manufacturer to send the retained labels sample.
The examination of the VVM color from three sources representing three
different stages showed that all VVM squares were the same color/hue. VVM
reading in all samples corresponded to the start point. This means that
VVMs were NOT exposed to any heat since they were manufactured.
On the other hand, it is true that the starting color of the VVM square had
been printed as white in WHO training materials. For more than a year now,
all documents/reports showing VVM have been printed with the correct light
shade of blue/grey. This was also reinforced in a meeting held with vaccine
manufacturers in Delhi in January this year. Electronic files including
correct VVM illustrations were distributed to all local vaccine manufacturers.
We would also like to announce the publication of a new WHO document
"Getting started with vaccine vial monitors (WHO/V&B/02.35)" which replaced
the old document "Vaccine vial monitors and open-vial policy: Questions and
answers WHO/EPI/LHIS/96.01)". The new document can easily be accessed and
downloaded from the following URL:
http://www.who.int/vaccines-documents/DocsPDF02/www716.pdf
With this message we are also attaching two WORD documents (small in size)
to assist countries, programmes, all organizations and partner agencies as
well as vaccine manufacturers who wish to include VVM illustrations in
their publications, documents, reports and/or product inserts. The first
attached document taken from the above mentioned WHO publication is an
illustration of how to read a VVM. We strongly urge all involved parties
NOT to redraw VVM as a grey circle and a white square in the middle, and
only use the illustrations that WHO provides. The second document shows a
VVM with NO heat exposure (this image is purposely done in black and white
for printing purposes). We should also draw the attention to the fact that
training materials are often photocopied resulting in the disappearance of
slight differences in shades of colors. Even if the original illustration
had the correct color, the photocopies will show the square as pure white.
"Snow-White" is not a feature of the VVM square. It is only in stories...
"Once upon a time, there lived a beautiful princess named Snow White..."
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