Knowledge and Practices of health workers of Cold Chain

Immunization is an important means of controlling serious infectious diseases. Careful attention to vaccine storage is essential to ensure optimal vaccine effectiveness. The system used for keeping and distributing vaccines in good condition is called the cold chain.

The main objective of this study was to assess cold chain utilization and the knowledge and practices of heath care workers at primary health care facilities in Riyadh and Eastern province of Saudi Arabia. The study was conducted by a cross sectional approach. A stratified random cluster sampling technique was used to obtain a random sample of 60 health facilities; 37 Governmental (GHF) and 23 private (PHF). A standardized data collection form was designed both to evaluate cold chain components at each health center and to collect relevant information from health workers. Assessment of knowledge of participating health workers of different aspects of the cold chain was done by means of a composite score developed based on the questions they were asked. A correct answer was given a score of 1 and an incorrect answer 0. In this manner, the possible score range was 15-72. In the absence of any standard criteria of scoring for such knowledge questions, this median score of 55.5 was used as a cutoff point to split the health workers into two categories: High knowledge group (score of 55.5 to 92) and low knowledge group (score of 15 to 55).

In Riyadh, 37 health facilities were included; 22 (59.5%) GHF and 15 (40.5%) PHF. A vaccination room was available at all GHF, compared to 73.3% of PHF. The vaccination room was well ventilated at 68.2% of GHF and 46.7% of PHF. One refrigerator reserved for EPI vaccines was available at 68.2% of GHF and 66.7% of PHF. However, the positions of most refrigerators were not ideal, since most were kept close to the wall with a space of under 30 cm at 63.6% of GHF and 80% of PHF. Positioning of the refrigerators was reasonable regarding not being directly exposed to sunlight at 68.4% of GHF and 100% of PHF.

Refrigerators contained two compartments (cooling and freezing) at 95.5% of GHF and 93.3% of PHF. Refrigerators had tightly closed doors, were fixed in place and in operating condition at all GHF and PHF. The refrigerator was solely used for storage of EPI vaccines in 90.9% of GHF and 100% of PHF. Water bottles were available at the bottom part of the refrigerator in 99.0% of GHF and 53.3% of PHF.

On examination of the freezer compartments, the ice thickness was less than 5mm. in 54.5% of GHF compared to 75% of PHF. Ice packs were found in the freezers in 100% of both GHF and PHF. The regulator thermometer was available in 95.5% of GHF and 66.7% of PHF. The degree was 4°C in 38.8% of GHF and 50% of PHF. The thermometer was placed at the upper refrigerator drawer in 95.2% of GHF compared to 70% of PHF. The freezer watch indicator was available at only 4.5% of GHF and was located in the freezer. The temperature degree reading during the visit-time was 1°. The temperature recording card was available at 95.5% of GHF compared to 46.7% of PHF.

A vaccine register containing all information on each vaccine was available at 100% of GHF and 40% of PHF. Another register was kept for recording vaccine expiry dates at all GHF, and was regularly updated at 95.5%. The 'same was available at 53.3% of PHF and information was regularly updated at 37.5%. A substitute for electric current in case of disconnection was available at 31.8% of GHF compared to 100% of PHF.

All workers in the vaccination clinics were females, of whom in GHF 16 (72.7%) were Saudi and 6 (27.3%) non Saudi, compared to 2 (13.3%) Saudi and 13 (86.7%) non-Saudi in PHF. Table 1 represents knowledge of cold-chain elements.

Written guidelines on the cold chain were available at 40.9% of GHF, compared to 33.3% of PHF. Among GHW, 59.1% had previously read official guidelines for cold chain maintenance compared to 40% of PHW. Only 14.5% of GHW had received prior training compared to 26% of PHW.

In the Eastern province, 23 health facilities were included in the study; 15 (65.2%) GHF and 8 (34.8%) PI-IF. A vaccination room was available at all GHF, compared to 50% of PI-IF, and was well ventilated at all GHF compared to 65.5% of PHF. A refrigerator for reserving EPI vaccines was available at all GHF and 87.5% of PHF. Refrigerators were kept at a distance of 30 cm from the wall at 93.3% of GHF compared to 37.5% of PHF, and were not directly exposed to sunlight at 80% of GHF and 100% of PHF. They had tightly closed doors, were fixed in place and in operating condition at all GHF and PHF.

The refrigerator was used for storage of EPI vaccines in all GHF and PHF, but was also used for storage of drugs in 20% of GHF and 62.5% of PHF. Water bottles were kept at the bottom drawer in 93.3% of GHF and 75% of PHF. Ice thickness in the freezer was less than 5mm in 93.3% of GHF and 75% of PHF, and it contained ice-packs in all GHF and PHF. The regulator thermometer was avail-able in all GHF and PI-IF, and was placed in the freezer or second drawer (50%). The freezer watch indicator was available at only 26.7% of GHF and was located in the freezer. Its temperature at the time of visit was 4° in all GHF, where also a temperature register was available, compared to 87.5% of PI-IF. A vaccines register was available at 93.3% of GHF and 75% of PHF. A register for recording vaccine expiry dates was available at 73.3% of GHF and 62.5% of PI-IF, and was regularly updated at all GHF and PHF. A substitute for electric current shortage was available at 53.3% of GHF and 71.4% of PHF.

All workers were females, 14 (93.3%) Saudi and 1 (6.7%) non Saudi in GHF compared to all non-Saudi in PHF. (For knowledge see table 1).

Guide lines on cold chain were available at 93.3% of GHF and only 37.5% of PHF. Among the total, 93.3% of GHW had read official guidelines for cold chain maintenance compared to 62.5% of PHW. Only 86.7% of total GHW had received training in cold chain maintenance compared to 75% of PHW.

The workers knowledge varied on different aspects of the cold chain. On the basis of the cumulative score, 30 (50%) workers were included in the high knowledge group and 30 (50%) in the low knowledge group. A statistically significant difference in knowledge of both groups was found in case of sector (governmental better than private, p-value <0.05), nationality (Saudis better than non-Saudis, p-value <0.05), previous reading on cold chain maintenance (p<0.05), and previous training (p-value <0.001).

Careful attention to vaccine storage is essential to ensure optimal vaccine effectiveness. Once vaccine potency is lost, the vaccine will no longer provide protection against the target disease. Vaccines are heat sensitive and have limited shelf lives. All vaccines are to some degree unstable. Their potency, and therefore the protection they give against disease, decreases over time. On the other hand, some vaccines may be damaged by freezing, such as DTP, Hepatitis B, DT, and TT. Others have to be kept frozen, such as OPV, Measles, Mumps, and yellow fever. Some vaccines are damaged by exposure to strong light as well as heat such as BCG and measles.[1,2] The cold chain system is, therefore, a very important component of an immunization program. Some previous studies have shown that knowledge of health workers about cold chain was inadequate.[3,4]

WHO recommendations state that the refrigerator inside the vaccination room should be placed away from sunlight and at least 15 cm away from the wall; defrosting should be done when the thickness of ice reaches 5 mm or more, and during defrosting vaccines should be left in another refrigerator or in an ice box. Water bottles should be kept in the lower part of the refrigerator; no materials should be stored in the EPI vaccines refrigerator except the EPI vaccines; thermostat should be placed in the first drawer of the refrigerator; refrigerator temperature registering record should be changed monthly; and the refrigerator temperature recorded twice daily. EPI vaccines and diluents should be stored between +2°C and +8°C, and should not be left to freeze. Each vaccine and its diluent have a recommended position inside the refrigerator, and recommended duration of storage after vial opening.

In this study, the majority of health workers managed to answer part of questions correctly. In general, the level of knowledge of GHW was better than PHW in both Riyadh and Eastern province, in spite of the fact that workers in Eastern Province claimed to previously read about cold chain more than Riyadh workers. It was recommended to hold training courses on cold chain maintenance to all workers before working in the vaccination field, and periodically to bring current workers knowledge up-to-date. The importance of cold chain maintenance and its significance should be emphasized to all workers in the vaccination field.