ABSTRACT
Primary vaccine failures can occur after high immunization coverage has been achieved. Healthcare workers’ knowledge and practices are influential factors in preventing vaccine failures. Adequate knowledge and practices in the cold chain system are important to keep potency of vaccines and effectiveness of immunization. This cross-sectional study was performed to assess healthcare workers’ knowledge and practices regarding an expanded program on immunization and the cold chain system in Kalasin, Thailand. Data collection methods included interviews, observations and document audit. Ninety primary care units and 117 respondents were selected. Only 55.6% of respondents provided correct answers for questions regarding the immunization schedule of school children and 59.0% of respondents answered correctly for questions about Measles-Mumps-Rubella Vaccine. Healthcare workers in hospitals had better knowledge than healthcare workers in health centers (P<0.001). Healthcare workers who had sufficient training had better knowledge than healthcare workers who had no training (P<0.001). Only 61.1% of primary care units recorded the temperature in the vaccine refrigerator twice a day and 63.3% of primary care units had a flowchart regarding what to do when there is an electric power failure. About 13% of vaccine refrigerators had temperatures outside the recommended range of 2 to 8°C. Practices in hospitals were also better than those in health centers (P=0.001). Knowledge and practices were significantly different between healthcare workers in hospitals and in health centers. Coverage training and regular supervision on vaccine handling and the cold chain system are recommended, especially for health centers in remote areas.
Key Words: Expanded program on immunization, Cold chain system, Knowledge, Practices, Thailand
INTRODUCTION
An expanded program on immunization (EPI) was launched in 1974 by the World Health Organization (WHO) with the aim of controlling vaccine-preventable diseases, such as tuberculosis, diphtheria, pertussis, tetanus, polio and measles.1,2) Immunization has been proved to be one of the most cost-effective parts of health promotion since in many countries after achieving high immunization coverage, the morbidity and mortality rates of vaccine-preventable diseases tended to decline.3,4) On the other hand, vaccine-preventable diseases have remained a serious concern in some areas where immunization coverage is not high.5-7) In 2008, WHO ascertained that the number of deaths due to vaccine-preventable diseases among children under five years from all over the world was about 1.7 million per year, and most of the deaths were in developing countries.8)
Published studies have shown inadequate knowledge and practices of healthcare workers regarding EPI and the cold chain system in many places in the world, especially in remote areas.9-12) A previous study found that increasing knowledge regarding EPI and the cold chain system for personnel could increase vaccination coverage and increase the efficiency of EPI and cold chain practices.13) A cold chain is a system for storing and transporting vaccines in a potent state from the manufacturer to the person being immunized. The cold chain system comprises three major elements: personnel, equipment and procedures.2) Some published studies found that vaccine-preventable disease outbreaks in areas that had high immunization coverage may have occurred due to primary vaccine failure.14-16) Vaccine failure can be divided into two categories: primary and secondary vaccine failure. Primary vaccine failure means no immunity after immunization due to lack of initial seroconversion. Secondary vaccine failure means loss of immunity after initial seroconversion.17,18) Primary vaccine failure can happen by either inactive vaccine or inadequate host response. Insufficient cold chain system and practices are possible causes of primary vaccine failure due to inactive vaccines.19,20)
Thailand is a country in Southeast Asia that is administratively divided into 76 provinces which are further divided into districts and sub districts, respectively. EPI has been integrated into the healthcare service system of Thailand since 1977.21,22) Thailand achieved high immunization coverage rates for Bacillus Calmette-Guérin vaccine (BCG), Diphtheria–Pertussis-Tetanus vaccine (DPT), Oral Polio vaccine (OPV) and Measles of 99, 99, 99 and 98 percent, respectively, although there are still reported cases of vaccine-preventable diseases.23,24)
There has been no published study about healthcare workers’ knowledge and practices regarding EPI and the cold chain system in Kalasin Province. Therefore, it is necessary to conduct this study with the objective of assessing healthcare workers’ knowledge and practices regarding EPI and the cold chain system at health centers and hospitals in Kalasin Province.
MATERIALS AND METHODS
This cross-sectional study was conducted in Kalasin Province during July to September 2010. There was one general hospital in the central area of the province, and 13 community hospitals in the central area of the districts. In outlying areas in sub districts there were 157 health centers. All of those facilities together provided healthcare services covering 950,000 people in 18 districts of Kalasin Province.25)
In Thailand the primary care unit (PCU) provides primary healthcare services, such as immunization, health promotion and antenatal care. In hospitals, the PCU is a department of the hospital, but at health centers the PCU means the whole health center. There are 171 PCUs in Kalasin Province.
A total of 90 PCUs were selected. We selected 76 units from the health centers by simple random sampling and all 14 units from the hospitals were selected. In the 76 health centers, one healthcare worker who was responsible for EPI was selected by random sampling from each health center. In hospitals, 41 healthcare workers were selected from among all personnel responsible for EPI and were present in the office on the visit day. Since there were only 14 hospitals in Kalasin Province, we then collected data from all hospitals this way to increase the sample size inside central areas.
Our questionnaire and checklist were adapted from the questionnaire and checklist of the Disease Control Department, Thailand Ministry of Public Health (MoPH). The MoPH questionnaire and checklist were usually used for EPI’s supervision activities in Thailand. MoPH also used that questionnaire to evaluate healthcare workers’ knowledge after training regarding EPI and cold chain management. MoPH experts conducted the questionnaire and handled the checklist based on the cold chain training manual for health workers produced by WHO. The questionnaire consisted of two sections as follows. 1. General information and demographic characteristics of respondents. 2. Knowledge regarding EPI and the cold chain system of respondents. The checklist had three sections as follows. 1. Practice in cold chain system and equipment. 2. Immunization registers and report system. 3. Manual and Guidelines for EPI and cold chain management that were produced and distributed to PCUs by MoPH. The staff from the Health Promotion Division of the Kalasin Public Health Offices went to PCUs and used the questionnaire to collect data about knowledge regarding EPI and the cold chain system and used the checklist for direct observation and document audit about practices and equipment regarding EPI and the cold chain system.
Collected data were analyzed using the Statistical Package for Social Science (SPSS) program version 16.0 (SPSS Inc., Chicago, IL, USA). Frequencies, percentages, mean and median were used to describe demographic characteristics, knowledge and practices. Knowledge and practices were assigned a score of 1 and 0 for correct and false responses, respectively. Total score of knowledge and total score of practices were calculated. Independent t-test was used to compare means of total scores. In cases where the distribution of total scores by healthcare worker characteristics was not normal, the Mann-Whitney U test was used to compare the median instead of the Independent t-test. Normality of distribution of data was assessed by the Kolmogorov-Smirnov test. Chi-square analyses were used to compare categorical variables, and a P value of < 0.05 was considered statistically significant. Permission to collect data for this study was approved by the Kalasin provincial chief medical officer who was the chief executive officer of the MoPH, Thailand at the provincial level.
RESULTS
General information of respondents
Table 1 shows the characteristics of the 117 respondents, 90.6% of whom had a bachelor degree level of education and the rest had master degree level. 78.6% of respondents were nurses and 61.5% of respondents had work experience in EPI services of less than 2 years. Approximately 20% had no training regarding EPI and the cold chain system. In total, among 23 respondents with no training, 22 worked in health centers.
Table 1.
Demographics of respondents
| Factors | No. of respondents (N = 117) |
Percentage |
|---|---|---|
| Level of education | ||
| Bachelor degree | 106 | 90.6 |
| Master degree | 11 | 9.4 |
| Position | ||
| Public health officer | 25 | 21.4 |
| Nurse | 92 | 78.6 |
| Years of service | ||
| < 2 year | 72 | 61.5 |
| ≥ 2 years | 45 | 38.5 |
| EPI a training | ||
| Yes | 94 | 80.3 |
| No | 23 | 19.7 |
a EPI = Expanded program on immunization
Knowledge
From 15 questions about knowledge regarding EPI and the cold chain system, our study revealed that questions with few correct answers concerned dose and route of DPT (63.2%), dose and route of measles vaccine (64.1%), and dose and route of measles-mumps-rubella vaccine (MMR) (59%). A vaccination interval longer than scheduled will not decrease the effect of immunity (60.7%). A person who comes late on the schedule can receive his or her next vaccination; it is not necessary to restart (63.2%). An immunization schedule is in place for schoolchildren (55.6%), and if vaccinations cannot be started on time per schedule, they should begin as soon as possible (61.5%). Details are summarized in Table 2.
Table 2.
Correct answers about EPI knowledge of respondents
| Questions | Number (percentage) | Number (percentage) | Total | ||||
|---|---|---|---|---|---|---|---|
| Health center | Hospital | P | No training | Have training | P | ||
| n=76 | n=41 | n=23 | n=94 | N=117 | |||
| Dose and route of vaccine tetanus in pregnancy | 60 (78.9) | 38 (92.7) | .055 | 18 (78.3) | 80 (85.1) | 0.527 | 98 (83.8) |
| Dose and route of vaccine Japanese encephalitis | 42 (55.3) | 37 (90.2) | <.001 | 12 (52.2) | 67 (71.3) | .080 | 79 (67.5) |
| Dose and route of vaccine BCG | 53 (69.7) | 39 (95.1) | .001 | 13 (56.5) | 79 (84.0) | .009 | 92 (78.6) |
| Dose and route of vaccine Hepatitis B | 44 (57.9) | 36 (87.8) | .001 | 8 (34.8) | 72 (76.6) | <.001 | 80 (68.4) |
| Dose and route of vaccine DPT | 39 (51.3) | 35 (85.4) | <.001 | 4 (17.4) | 70 (74.5) | <.001 | 74 (63.2) |
| Dose and route of vaccine Measles | 42 (55.3) | 33 (80.5) | .007 | 7 (30.4) | 68 (72.3) | <.001 | 75 (64.1) |
| Dose and route of vaccine MMR | 32 (42.1) | 37 (90.2) | <.001 | 5 (21.1) | 64 (68.1) | <.001 | 69 (59.0) |
| Vaccinated interval longer than scheduled, no decreased effect of immunity | 38 (50.0) | 33 (80.5) | .001 | 8 (34.8) | 63 (67.0) | .005 | 71 (60.7) |
| Low-grade fever person can receive vaccination | 54 (71.1) | 31 (75.6) | 0.598 | 10 (43.5) | 75 (79.8) | <.001 | 85 (72.6) |
| No need to restart if vaccination is late | 42 (55.3) | 32 (78.0) | .015 | 5 (21.1) | 69 (73.4) | <.001 | 74 (63.2) |
| DPT loses potency by freezing | 43 (56.6) | 34 (82.9) | .004 | 9 (39.1) | 68 (72.3) | .003 | 77 (65.8) |
| Immunization schedule of schoolchildren | 36 (47.4) | 29 (70.7) | .015 | 8 (34.8) | 57 (60.6) | .025 | 65 (55.6) |
| Asymptomatic HIV child can receive vaccine | 52 (68.4) | 29 (70.7) | 0.796 | 9 (39.1) | 72 (76.6) | <.001 | 81 (69.2) |
| Must use open vaccine within 24 hr | 46 (60.5) | 31 (75.6) | 0.101 | 6 (26.1) | 71 (75.5) | <.001 | 77 (65.8) |
| If cannot start on time, begin vaccination as soon as possible | 40 (52.6) | 32 (78.0) | .007 | 11 (47.8) | 61 (64.9) | 0.132 | 72 (61.5) |
BCG = Bacillus Calmette-Guérin; DPT = Diphtheria–Pertussis-Tetanus; MMR = Measles-Mumps-Rubella; EPI = Expanded program on immunization
The total score of knowledge from the 15 questions were calculated. The mean total score was 9.54. Maximum score and minimum score were 15 and 3, respectively. In Table 3, the mean and median total score of knowledge regarding EPI and the cold chain system were compared by Student’s t-test and Mann-Whitney U test, respectively. Comparisons showed that the mean total score in the group of respondents who worked in hospitals was significantly higher than in those who worked in health centers, the mean in the group with work experience of more than or equal to two years was significantly higher than in the group of respondents who had experience of less than two years. The group of respondents who had training regarding EPI and the cold chain system also had a significantly higher median total score than in the group with no training.
Table 3.
Compare mean and median of total score of knowledge regarding EPI
| (Total score = 15) | ||||
|---|---|---|---|---|
| Variables | n | Mean (SD) | Median (IQR) | P |
| Workplace a | ||||
| Health center | 76 | 8.72 (2.97) | 9 (4.75) | |
| Hospital | 41 | 11.07 (2.35) | 11 (3.50) | < .001 |
| Work experience a | ||||
| < 2 years | 72 | 8.65 (2.96) | 9 (5.00) | |
| ≥ 2 years | 45 | 10.97 (2.44) | 11 (4.00) | < .001 |
| Training b | ||||
| No training | 23 | 5.60 (1.72) | 5 (2.00) | |
| Have training | 94 | 10.51 (2.37) | 10 (3.00) | < .001 |
| Position b | ||||
| Public health officer | 25 | 8.84 (2.89) | 9 (5.00) | |
| Nurse | 92 | 9.73 (2.99) | 10 (4.75) | 0.215 |
a Use Student’s t-test (compare mean)
b Use Mann-Whitney U test (compare median)
EPI = Expanded program on immunization
Practices
The findings from direct observation about equipment and practices regarding the cold chain system in PCUs are summarized in Table 4. We found that 100% of PCUs had no expired vaccines in refrigerators and in 86.7% of PCUs the temperature inside refrigerators was in the range of 2–8°C. A total of 95.6% of PCUs that kept OPV on the freezer shelf, and 100% of PCUs kept DPT, diphtheria-tetanus vaccine (DT) and hepatitis B vaccine on the normal shelf.
Table 4.
Correct practices regarding cold chain system and equipment in PCU
| Variables | Number (percentage) | P | ||
|---|---|---|---|---|
| Health center n=76 |
Hospital n=14 |
Both N=90 |
||
| No expired vaccine found in refrigerator | 76 (100.0) | 14 (100.0) | 90 (100.0) | – |
| Have temperature chart and record temperature in refrigerator 2 times daily | 44 (57.9) | 11 (78.6) | 55 (61.1) | .040 |
| Have special refrigerator plug | 46 (60.5) | 13 (92.9) | 59 65.6) | .029 |
| Maintain stock card for vaccines | 31 (40.8) | 12 (85.7) | 43 (47.8) | .002 |
| Have flowchart of electricity breakdown | 47 (61.8) | 10 (71.4) | 57 (63.3) | .013 |
| Have ≥ 4 ice packs on freezer shelf | 68 (89.5) | 14 (100.0) | 82 (91.1) | 0.349 |
| No used needles retained in vaccine vial | 70 (92.1) | 14 (100.0) | 84 (93.3) | 0.585 |
| Keep refrigerator temperature at 2–8°C | 65 (85.5) | 13 (92.9) | 78 (86.7) | 0.683 |
| Keep OPV on freezer shelf | 72 (94.7) | 14 (100.0) | 86 (95.6) | 1.0 |
| Keep DPT, DT, Hepatitis B vaccine on normal shelf | 76 (100.0) | 14 (100.0) | 90 (100.0) | – |
OPV = Oral polio vaccine; DPT = Diphtheria–Pertussis-Tetanus vaccine; DT = Diphtheria-Tetanus vaccine; EPI= Expanded program on immunization; PCU = Primary care unit
Only 47.8% of PCUs maintained stock cards for vaccines and 61.1% of PCUs had a temperature chart and recorded the temperature inside the refrigerator 2 times daily. Only 63.3% of PCUs had a flowchart about what to do in case of a power outage, and 65.6% of PCUs had a special plug for refrigerators.
Table 5 shows practices of PCUs regarding immunization records and registers. The number of PCUs that had an immunization register for every target groups was as follows: 83.3% in the group of children below five years, 70% in the group of pregnant women and 66.7% in the group of school-age children. Otherwise, the details of records such as lot numbers of used DT vaccines were recorded by only 55.6% of PCUs, the vial numbers of used MMR vaccines were recorded by only 38.9% of PCUs, and 82% of PCUs maintained a register of immunization coverage.
Table 5.
Correct practice regarding immunization registers and record in PCU
| Records | Number (percentage) | P | ||
|---|---|---|---|---|
| Health center n=76 |
Hospital n=14 |
Both N=90 |
||
| Maintain register in group of children < 5 year | 62 (81.6) | 13 (92.9) | 75 (83.3) | 0.450 |
| Record DTP lot no. | 48 (63.2) | 13 (92.9) | 61 (67.8) | .031 |
| Maintain register in pregnant woman group | 49 (64.5) | 14 (100.0) | 63 (70.0) | .008 |
| Record DT lot no. | 38 (50.0) | 12 (85.7) | 50 (55.6) | .013 |
| Maintain register in school children group | 46 (60.5) | 14 (100.0) | 60 (66.7) | .004 |
| Record MMR vial no. | 27 (35.5) | 8 (57.1) | 35 (38.9) | .007 |
| Maintain register of immunization coverage | 60 (78.9) | 14 (100.0) | 74 (82.2) | .066 |
DPT = Diphtheria–Pertussis-Tetanus vaccine; DT= Diphtheria-Tetanus vaccine; MMR = Measles-Mumps-Rubella vaccine; PCU = Primary care unit
In Table 6, the median total score of practices regarding EPI and the cold chain system were compared by the Mann-Whitney U test. Comparisons showed that median total scores of practices of PCUs in hospitals were significantly higher than those of PCUs in health centers.
Table 6.
Compare median total score of practices regarding EPI in PCU
| Variables | Practices regarding Cold chain system (total score=10) |
Practices regarding Registers and records (total score=7) |
|||
|---|---|---|---|---|---|
| n | Median (IQR) | P | Median (IQR) | P | |
| Work place a | |||||
| Health center | 76 | 8.50 (2.0) | 4.00 (2.00) | ||
| Hospital | 14 | 9.50 (1.0) | .001 | 6.00 (1.00) | < .001 |
a Use Mann-Whitney U test
EPI = Expanded program on immunization; PCU = Primary care unit
The present study found that the total of respondent PCUs (100%) had at least one item from three of the standard manual and practices guidelines regarding the cold chain system and EPI that were provided by MoPH, and 76.7% of respondent PCUs had all three items.
DISCUSSION
This study showed that healthcare workers in hospitals have better knowledge than healthcare workers in health centers. The knowledge of healthcare workers who have longer work experience in EPI was better than that of healthcare workers who have less work experience. Moreover, trained healthcare workers had better knowledge than untrained healthcare workers. Practices in the cold chain system in hospitals were also significantly better than practices in health centers. These findings were consistent with previous studies in other areas.9-12)
Personnel who had no training regarding EPI and the cold chain system invariably worked in health centers. The reason may be the intense workload at health centers. Most health centers in Kalasin Province have only three or four personnel who are responsible for broad service in primary health care.25)
The questions with few correct answers pertained to knowledge about the immunization schedule of schoolchildren (55.6%) and MMR vaccine (59.0%). If sufficient vaccine manual guidelines are available, healthcare workers can deal correctly with the dose and route of vaccine by following the guidelines, but our study also found that 23.3% of service units had incomplete manual guidelines. Actually, those documents were provided in the beginning by Thailand MoPH in hardback form and distributed to all PCUs and currently on the website of the MoPH; some softback copies are available. In cases where there are incomplete manual guidelines in PCUs, complete softback copies can be provided on the website and the staff can be encouraged to access the information.
Regarding consistency with previous studies, one disturbing finding pertained to inadequate refrigerator management that included failing to record the temperature inside the refrigerator twice daily. The PCU might have a flowchart detailing what to do when an electrical power outage occurs and how to maintain refrigerator temperature within the recommended range.26,27) WHO recommended that the temperature during storage should be kept at 0–4°C for OPV and 2–8°C for other vaccines.2,14) Temperatures in vaccine refrigerators should be read and recorded twice a day.12,14) The WHO recommendations were effective for self monitoring to prevent breaking the cold chain that can reduce the potency of vaccines and contribute to primary vaccine failure.
Most registers and records regarding immunization activity were kept but in some important details were neglected; for example, only 38.9% of PCUs verify who received MMR from the same vial, and only 55.6% check who received DT from the same lot number. Thus, if problems occur in a particular lot of vaccines or vials of vaccines, with such as manufacturing defects, PCUs cannot know who will be affected by those defective vaccines.
We cannot actually identify inactivated vaccines except by potency tests, which are expensive and not widely available in Thailand. Our study had limitations in time and budget. Further studies that can explore relationships among knowledge, practices and vaccine potency are warranted. Also, a larger-scale study should be considered.
Although this study is not representative of all of Thailand or other areas where high immunization coverage was achieved, it does show inadequate management can occur in Kalasin Province where immunization coverage is high. Although raising immunization coverage is important, the quality of vaccine storage and handling is equally important.
In conclusion, there were gaps in knowledge and practices regarding the cold chain system among healthcare workers in hospitals and health centers in Kalasin Province. To ensure optimal immunization effectiveness, continuous training and regular supervision on EPI and the cold chain system are necessary. It is also strongly recommended especially for health centers in outlying areas.
ACKNOWLEDGMENTS
This study was supported in part by Kalasin Public Health Offices, MoPH, Thailand. The authors are grateful to Dr. Pisit Auevongkul who was the Kalasin chief medical officer, staff from the Health Promotion Division of the Kalasin Public Health Offices, and all respondents at PCUs in Kalasin Province. Our study was also supported in part by a non-profit organization, “Epidemiological and Clinical Research Information Network (ECRIN).” Finally, we would like to express our sincere gratitude to the Japanese Government, all lecturers and staff of the Young Leaders’ Program, Graduate School of Medicine, Nagoya University, Japan.
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