In the early 1950s an estimated 50 million cases of smallpox occurred every year.   The vaccine was widely use in the rich countries but it would deteriorate within three days of being taken out of a refrigerator and vaccination in tropical countries was effectively impossible.

Professor Leslie Collier, who died aged 90 this week in London, worked out a way to freeze-dry smallpox vaccine so that it could travel to areas with hot climates. Professor Collier’s re-formulated vaccine was put in 200-dose vials and carried to remote areas with saline solution to re-constitute the powdered vaccine, a pot for boiling needles and two plastic tubes – one for new needles and the other for used needles.

The table below gives WHO’s estimates of the potential stability of many of the vaccines that are widely used. This shows that at least half of them of them have the potential to be kept at ‘room temperature’ – that is, of course, not the same as a typical room temperature in a tropical climate.

(Temperature sensitivity of vaccines, World Health Organization, WHO/IVB/06.10, August 2006. More detailed information on vaccine stability can also be seen at:  http://www.path.org/publications/detail.php?i=1696)

In addition, as many as 30% of the drugs used in tropical climates need to be kept at ‘room temperature’ that is, at 25 degrees Celsius or less.

Can we merge the vaccine and drug supply chains into a single ‘room temperature chain’, or Controlled Temperature Chain, for the supplies that only need to be kept below 25 degrees Celsius?

Please post your comments below on why you think this may be a useful next step for health supply logistics or why you think it is not possible.

If common 25 degree C distribution for drugs and vaccines can achived, this will save fuel for the countries, reduce vaccine and drug wastage, and most importantly lower the risk of heat-damaged vaccines and drugs being given to patients.

After many years of discussion vaccine wastage rates are still not well documented and according to the Therapeutic Research Centre, hundreds of thousands of drugs and medications are discarded each year (quoted in the PHARMACIST’S LETTER / PRESCRIBER’S LETTER, October 2008, Volume 24, Number 241001).

Professor Collier’s work continues 60 years since he started it,  What are the chances that in 60 years’ time we will achieve the original goal of the Children’s Vaccine Initiative: a single dose of heat-stable vaccine given at birth to eliminate all vaccine-preventable diseases?

An obituary for Professor Leslie Colliers also describing his work in trachoma and chlamydia can be read at http://www.guardian.co.uk/science/2011/may/09/leslie-collier-obituary?INTCMP=SRCH

For more on this topic see: Labelling vaccines to reflect their true heat stability, on TechNet21.org at http://www.technet21.org/index.php/forum/technet21/vaccine-presentation-packaging-and-wastage/2631-labeling-vaccines-to-reflect-their-true-heat-stability.html