POST 00662E : VACCINE FORECAST
Follow-up on Post 00649E
13 April 2004
________________________________
This posting starts with a contribution from Alejo Bejemino
(mailto:[email protected]) from UNICEF/Afghanistan who also attaches a
spreadsheet as an example of comparing two methods of vaccine forecast.
Next is an exchange generated by the previous posting from Alasdair Wylie.
It involves Robert Steinglass (mailto:[email protected]) from BASICS,
Michel Zaffran (mailto:[email protected]) Olivier Ronveaux
(mailto:[email protected]) and Patrick Zuber (mailto:[email protected]) all
three from WHO and Alasdair himself (mailto:[email protected]).
It has been put in chronological order to facilitate reading.
Three attachments are related to this exchange. Apart from the WHO
guidelines are copies of Tables 3. and 4. of the country annual report to
GAVI that Alasdair refers to.
________________________________
I agree with Alasdair that forecasting DPT requirements based on DPT3
multiplied by a factor will render shortage of vaccines. I could not follow
the justification of the formula and I think further explanation with
examples is more helpful.
Target Population method for the forecast of vaccines is ideal but when it
comes to the implementation at field level the team wise method is more
relevant.
In the team wise method, each vaccination team is given certain number of
vials of every vaccine when they go for outreach vaccination. The quantity
varies depending on the distance of the vaccination sites and their target
for that day.
Based on field experience both methods are not accurate. However a
combination of both methods will yield a safe level of vaccines.
Regards.
Alejo
Alejo H. Bejemino
EPI Cold Chain Consultant
UNICEF Afghanistan
_______________________
Robert shared this with me. As indicated in my comments which Claude has
just posted I think the basic question is whether DPT1 should be used at
all; but if it is, there is a direct source for it, the JRF, which removes
the need for a calculation with a "factor".
Was ATT consulted about this?
Best regards , Alasdair
---------------------------
Hi, Michel,
Not sure who to direct this to. I suppose you are thinking about giving
guidance to countries on how to apply the new GAVI Board guidance on
vaccine calculation based on DTP1, but I wanted to let you know that I
became aware today of at least one country (Mali) currently scratching its
head, trying to figure it out. The "formula" that I have seen mentioned in
various documents doesn't appear to work unless some additional information
is provided to guide countries.
All the best,
Robert
----------------------------
Thanks Robert for the heads up
Can you be more specific about the additional information required?
Michel
-------------------------------------
The formula that I saw mentioned a "factor" for wastage. For starters, that
would need to be explained. What factor?
If you (or the Gavi Secretariat) haven't already done so, I suggest that
you apply hypothetical figures to an example of how this formula is
supposed to work in a country, as guidance.
Frankly, when I plugged in hypothetical figures, I was not happy with the
result, leading me to believe I did not understand the indicator.
Robert
------------------------------------
As promised, please find attached the guidelines from WHO regarding
estimating vaccine needs. The WHO approach relies a lot on using historical
utilization data to adjust calculations after one year. For the first year,
we feel it is essential to avoid stockouts and recommend a conservative
approach.
As a result, the method proposed might overestimate needs if applied over a
time period longer than 1 year.
Please let us know if you like to discuss this further.
Patrick
---------------------------
Attached are the guidelines developed within WHO (led by VPP) on the
calculation formula of estimated needs which were subsequently adopted by
GAVI, with the e-mail sent by VPP. The use of a 'factor' to correct for
drop-out (DTP1-DTP3) is a decision of the Secretariat because they do not
have the projected DTP1 information in the GAVI annual report. Hence the
Secretariat will use the available information to take the dropout into
consideration, i.e. DTP1-3 dropout from the JRF. The projected DTP1 is not
asked to countries in the current annual progress report.
I hope this clarifies.
Best regards
Olivier
----------------------
Olivier
1. The WHO guidelines you attached seem clear enough overall (although some
curious wording - what for example does "prevents unnecessary demands" in
Principle# 1 mean?) and it makes clear that the calculation is based on
target population.
2. If the above is what GAVI has adopted, fine, but then the problem is
with the wording of your "new policies" announcement as reported in the
GAVI Update to which I reacted, which showed DTP1 as the base for
calculation and so was (unintentionally) misleading. The guideline makes it
(more or less) clear that where DTP1 comes in is for the "expected
coverage" element in the vaccine calculation. Perhaps a clarification in
GAVI Update would be useful.
3. I am still not clear however about the need for a DTP1 -DTP3 drop-out
factor to work out DTP1. The latest version of the website form for country
annual report to GAVI (Feb 2004), which you have prompted me to look at,
does indeed show a line for DTP1 in Table 3 page 11 (attached); so no need
even to look at the JRF.
4. I still think that the issue about using "expected coverage" (e.g. for
DTP1) needs to be discussed. If it is significantly less than 100% and
vaccine is supplied on that basis then there is the risk of
institutionalising "left outs" unless the local programme adopts specific
measures aiming to increase DTP coverage, drawing if necessary on the
buffer stock.
5. Regarding buffer stock, I note that the "example" formula at the end of
the WHO guideline
a) does not include the buffer stock element although it is stated earlier
that a buffer stock of 25% is usually included....
b) is inconsistent with Table 4 in the GAVI annual report (attached) in
that Table 4 does show the buffer (reserve) stock element (as well as, of
course, the projected stock balance at end of period). Also Table 4 does
not explicitly include the "expected coverage" element as distinct from
target population (birth cohort), as the guideline formula does.
I think some consistency in such things would help.
Regards
Alasdair
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