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To the Editor (Dr. AbdulRauf Ghulam, Vaccination Dept PHCC, Qateef - Hashim Abu Alrahi Head of department of preventive medicine, PHC, Qateef)

From: Dr. Abdul Rauf Ghulam Mohammad. (In charge of the vaccination department in Primary Health Care Qateef. Eastern Province. Contact Phone no. 03-8520435, E mail:, Dr. Hashim Alawi Abul rahi. (Head of the department of Preventive medicine and chief epidemiologist. Primary Health Care Qateef. Eastern Province. Phone No. 03-8541585, E mail:

Reference to your article "Knowledge and Practices of health workers of Cold Chain" by authors Dr Munira Al Zamil in the issue of Saudi Epidemiology Bulletin of Oct-Dec 2004, volume 11, Number 4.
We read your article with great interest. Articles on such topics are very rarely reported in the literature. It was a very brave attempt to write on this particular subject. I congratulate the authors on this bold attempt. Please keep it up. Naturally this subject attracts some comments and we do have few of them:
1- Acceptable range of the refrigerator temperature in which we can store our vaccines in the health center / hospital tertiary level is between 2-8°C (Editor's note), so there was no need to select only one figure (4°C) as a cutoff point
2- By freezer watch indicator if the authors meant 2 freeze watch indicator which is kept in that compartment of the refrigerator where you put DPT, DT, TT or HBV. It will give an irreversible change in the freezer watch indicator if the temperature reached below 0° C for at least one hour and then these vaccines should be destroyed and should not be used again. Freeze watch indicator is not kept in the freezer. We feel it was a misprint.
3- According to the MOH recommendation a paper sheet' for recording the expiry dates of the vaccines should be used. We normally use a sheet of paper with a list of refrigerator's content with the batch nos. and expiry dates and attach to the outside of the door of the refrigerator and hence it is very convenient to update. Registers are neither used nor recommended.
4- Only 14.5% of the Governmental health workers in Riyadh had received training in cold chain practices according to the article. It is really very alarming considering that it is a Governmental sector facility. Our experience in Qateef area about the lower quality of cold chain maintenance in private sector is similar to that mentioned in the article. It requires more training, supervision and follow up in that sector. We have a regular program regarding this and are implementing it.
5- In our area we have auto defrost refrigerators in both the private and governmental sectors. It is amazing that in your study, a large percentage (>45% GHF in Riyadh have ice thickness over 5mm in the freezer) is without this option or option not working.
6- I agree with the Editor's note that recommended distance between the wall and the refrigerator should be minimum 15 cm.
7- Now most of the authors believe that at health center level polio should be kept at 2-8°c. At Central and regional level, yes it should be kept frozen in the range of -15 to -25°C.
Reply from the Author: Dr. Munira Al Zamil (Field Epidemiology Training Program).
In response to their comments, we would like to thank them for reading the article with such interest, and we agree with their comments. The freeze watch indicator is an irreversible temperature indicator that is used to evaluate whether freeze sensitive vaccines have been exposed to freezing. If the freeze indicator is exposed to temperatures below 0°C (±1.5°C) for more than one hour, the indicator paper becomes stained with color. The freeze indicator should be kept above freezing temperatures, therefore it is placed with freeze sensitive vaccines in upright refrigerators.4
We regret the typing error for the percentage of Governmental Health Facilities in Riyadh where the ice thickness in the freezer compartments was less than 5mm. which should have appeared as 84.5% rather than 54.5%.
  1. MOH. Quality Assurance in Primary Health Care Manual by scientific committee of Quality Assurance in primary Health Care. First edition 1994.109-128
  2. WHO. Immunization in Practice; module 3 -The Cold Chain VVHO/EPI/TRAM/98.03Rev.1*. WHO Geneva 1998 p9.
  3. WHO. Guidelines for the establishing or improving national, regional and district vaccine stores. Global programme for vaccines and immunization. WHO/EPI/96.03 World Health Organization, Geneva 1996. p 4.
  4. WHO. The cold chain. Equipment performance specifications and test procedures. /freeze_watchtm.htm