This is motivated by John Lloyd's recent post about a supply chain for outreach immunization, which I found very interesting. My question is somewhat peripherally related though. As some background, I am an academic who focuses on supply chain analysis, and in particular, I have worked a fair bit on the WHO-EPI vaccine distribution chain over the last few years (I was part of the original HERMES team with Bruce Lee, Shawn Brown, Bryan Norman and others). My interest is mainly in the modeling (via mathematical models or via computer simulation) and analysis aspects, and I have developed a particular interest in outreach since very little seems to have been done in systematically modeling this aspect of vaccine delivery. However, I am having a very hard time understanding the modalities of outreach operations since these seem to be highly variable depending on which country we are talking about! From e-mail exchanges and conversations at meetings (such as the Global Health Supply Chain Summit) with professionals in the field, there seem to be no standard modes for outreach - unlike the overall distribution chain, which typically have a standard 4-level hierarchical structure with fairly standard equipment and vaccine replenishment times. For example, the way I was told outreach is conducted in India (Bihar state) is quite different from the way I was told it is handled in parts of Africa (Mozambique, I believe?).
Which brings me to my question. Is there any publication - paper, article, book/monograph - that describes how outreach immunization is conducted across the world? I'm not talking about planned campaigns, but rather, routine EPI vaccine delivery at remote locations via outreach. If there is no such publication, I was wondering if people in this forum who are involved in outreach would be willing to share how exactly outreach is done in their neck of the woods - just a two to three paragraph summary? For example, how frequently does it happen, whether outreach locations are repeated in some cyclic fashion over time, whether each outreach trip is a single point-to-point visit or whether multiple locations are covered in one trip, whether it occurs from IHCs or from higher levels such as a district facility, whether vaccine supplies for outreach are included as part of routine orders placed upstream, what kind of personnel and equipment constraints one needs to worry about, what are the main metrics used to assess performance of outreach, etc. etc. etc. I suspect the answers to these types of questions will vary quite a bit from place to place, but I'm just looking for the most common processes in use. It just seems that I need to understand the main aspects of outreach and how it relates to the overall EPI supply chain in order to make sure that any models I attempt to build are grounded in reality! I honestly believe that this aspect of immunization has not been studied enough and that there is much room for improvement.
If a few kind souls in this forum could take a few minutes to provide a brief overview of outreach at their location I would really appreciate it...