John Lloyd

Yes, I heard the announcement too on BBC World News.

I support the motivation and interest of individual researchers and the media to anounce potential 'innovations' in a cryptic 'Breaking News' style.

In this case, as in many other releases I have read, is that the innovation is premature and vanishes as quickly as it appeared! In this case, I hope that the issues that I am about to list will be considered:

Freeze dried format is, I admit, being used in the manufacture of an increasing proportion of new vaccines. However, this format is to be avoided in the future when there is better choices because:

- Until there are vaccine delivery devices that administer powder directly in widespread use, the vaccine has to be re-constituted (mixed with diluent); 

- The reconstitution of dried vaccine with diluent at the point of use is hazardous and the procedure is slow;

- Oral polio drops are enabling us to eradicate the disease without an injection and injected, killed polio liquid will gradually take over without an additional injection;

- Although freeze drying can achieve higher thermostability in storage than some liquid vaccines, it is very heat sensitive once reconstituted and must be used within 6 hours;

- Freeze drying is an expensive process requiring long term investment by manfacturers and some loss of flexibility.

John Lloyd