The difficult reality, however, is that the health care system in some of these geographies is so strained, and the people so widely dispersed (without many reliable methods of recall and followup contact), a second dose might never be given in more than three quarters of the population. And that would mean the outbreak would not be contained, at all. Add to this, that J&J's booster component is required to be grown up in chicken eggs -- a notoriously difficult way to acheive the pandemic volumes needed for the booster. [Just ask Baxter about its 2010-2011 era avian flu vaccine experiences, here.]
It is true (as Reuters is reporting) that Merck's trial in Geneva, Switzerland is presently on hold -- while four cases (of 59) of joint pain are evaluated -- to be sure that the malady is temporary, and reversing. Even so -- Merck's vaccine candidate (so far) shows the strongest single dose immune response.
And a single dose regimen may be the only practical way to contain this -- and other -- outbreaks. It is just too hard to do follow-up for second dosings, on vast swaths of rural, low infrastructure, migrant populations. Populations like those now afflicted in West Africa. The UN public health organizations -- and Doctors Without Borders -- have seen this, over and over, again.
So (and all of this is just my opinion), assuming that the joint pain and stiffness is temporary, in the Merck/NewLink Genetics candidate, I think Merck's vaccine will be the one deployed in Sierra Leone, at least this time around. Such temporary stiffness is not all that uncommon a side effect -- of several vaccines, already on market. . . . so we should not be too terribly surprised to see it appear here.
Now, let us hope that it is temporary -- because the alternative candidates present some real logistical nightmares -- in most of Africa -- where they will be most sorely needed.
