POST 00672E : VACCINE FORECAST
Follow-up on Posts 00649E, 00662E and 00671E
11 May 2004
________________________________
To pursue this discussion on vaccine forecast, follows an exchange between
Oleg Benesh (mailto:[email protected]) from Moldova, Robert Steinglass
(mailto:[email protected]) from the United-States (Project BASICS II)
and Alasdair Wylie (mailto:[email protected]) from the UK.
________________________________
Dear Robert and Alasdair,
I would like to share with you my concern that many programmes may have
included already the vaccine wasted for drop-out in their current estimates
of the vaccine wastage rate. It is an issue of calculation of the wastage
rate (or factor). This may happen if the number of administered doses is
defined based on the no. of children vaccinated with DTP3. Consequently all
vaccine doses administered to children who receive the 1st and 2nd dose but
not the 3d dose are accounted as "wasted" doses. Estimating vaccine needs
based on the coverage with the 1st dose in such a case will inflate
unnecessarily the estimated no. of doses.
Alternatively, in order to have a proper estimate of the number of all
administered doses there is a need to collect data on no. of children
vaccinated with each dose (DTP1, DTP2, DTP3 etc). I am not sure all
countries collect those data.
May ask for yours comments on that?
Regards,
Oleg Benesh
Medical Epidemiologist
National Center of Preventive Medicine
Republic of Moldova
--------------------------------------------------
from Robert Steinglass:
Oleg, hi!
Thanks for your message. I think it would be important for someone (WHO?)
to look into your statement that "many countries may have already included
the vaccine wasted for drop-out in their current estimates of the vaccine
wastage rate." It is becoming increasingly clear to me that some things
that we have assumed for a long time (e.g., that calculation of wastage was
a simple and straightforward matter that by now everyone already knew how
to do) might have been mistaken!
You discuss in your first paragragh "vaccine wasted for drop-out." I think
that is a confusing concept. Unless things have changed, I believe that
doses given to children who start but do not complete the series are not to
be considered as vaccine wastage. True, it adds to the cost of fully
protecting the population if a lot of vaccine is used to give first but not
last doses, but it is not classically "wastage." If countries are
calculating wastage that way, I would be concerned.
I know WHO has a new module on vaccine wastage. I picked it up in Turkey
and looked quickly through it. It seemed quite complicated in that it
proposed many formula for determining different aspects of the wastage
problem. If what you say is accurate, we may be introducing more complex
approaches before the basics are standardized and understood.
I agree with your second para: to collect wastage info you need to know
numbers immunized with DTP1, 2, and 3. I believe that all countries have
these consolidated data at national level. But it has not always been
reported for each dose to higher regional and global levels.
I still prefer the way that wastage was calculated in the NIS. As you know,
the numerator was simply the number of doses "used" and the denominator was
number of doses administered. This automatically generated a wastage factor
which could then be used to estimate vaccine requirements. In other words,
they skipped the step of coming up with a wastage rate.
I enjoyed seeing you again in Turkey.
All the best.
Robert
--------------------------------
from Alasdair Wylie:
Dear Oleg
I agree with all of Robert's points and would just add two. In order to
check if there is the problem you suspect, as far as country applications
to GAVI are concerned, the GAVI secretariat might wish to check (recheck)
the vaccine requirement/wastage factor calculations used by a sample of
countries from, say the last three rounds, perhaps with the assistance of
WHO/UNICEF/other agency country based staff.
If an intial miscalculation results in a country getting more vaccine than
it actually needs (or for that matter, less) then the normal annual
calculations which take into account expected end year stock balance should
help to rectify things - but might not on its own guarantee completely
solving the problem.
All the best
Alasdair
--------------------------------
from Oleg Benesh, with Alasdair's comments inserted in bold:
Dear Robert, Alasdair,
Thank you a lot for yours points. I fully support that an administered dose
can not be considered as a wasted one. There may be an additional issue
there: whether an administered dose is considered only if given
Il n'y a pas encore de réponse à ce message.