Analysis of vaccine losses by temperature changes in a Health Region from Minas Gerais State, Brazil

Introduction: Immunobiologicals are of great importance for the prevention and eradication of diseases. However, the lack of maintenance of the cold chain generates several problems related to losses of these substances, burdening an important amount of public resources. Objective: To analyze vaccine losses in a Health Region (Região Ampliada de Saúde Oeste) of Minas Gerais State in Brazil. Methods: This is a descriptive study, based on secondary data obtained through forms used by the regional health agency (Superintendência Regional de Saúde, SRS), to register losses of immunobiologicals due to temperature changes. Forms from February 2016 through January 2018 were analyzed. The data was organized and validated by double typing. Results: Vaccine losses were caused by lack of electrical energy (40.83%), followed by equipment failure (36.67%), and professional error (10%). As a consequence, 17,229 bottles of vaccines (65.78%) were discarded, corresponding to 111,145 doses. The financial loss was R$ 604,340.31. Conclusion: Losses of vaccines due to temperature changes were relevant in the studied region, damaging the budget for the local health network. Therefore, it is suggested that measures to minimize these losses should be adopted.


INTRODUCTION
The National Immunization Program (Programa Nacional de Imunizações -PNI) was created in 1973 by the Ministry of Health (MS), using basic vaccination strategies, which were developed to contribute to the control and eradication of vaccine-preventable diseases, cooperating with the maintenance of population health 1 .
In order to maintain their immunogenicity and efficacy, vaccines need to be kept at controlled and ideal temperatures, until the time of use 2 . The PNI has rules that must be strictly respected for the proper conservation of these substances. Such standards provide for the adequacy of vaccine rooms, which concerns lighting, organization, cleaning, provision of necessary materials and adequate training of professionals who will handle vaccines or work in vaccination rooms 3 . This training ranges from the  4 .
The RF is a technical-administrative system to sustain CF, through normative actions, planning, evaluation and financing 4 .
CF is the management system that involves the storage, conservation, handling, distribution and transport of immunobiologicals used in immunization programs, with the ultimate goal of ensuring the support of their immunogenic characteristics.
Maintaining the integrity of the CF is a major challenge that demands complete integration between the different levels, requiring responsibility and commitment from the immunization services and MS teams 5,6 .
The lack of CF maintenance generates several problems related to significant losses of immunobiologicals, these losses being As there are few studies related to the evaluation of the organizational and operational aspects of immunobiologicals, especially when it comes to maintaining CF, it is necessary to know the problems related to vaccine losses, especially preventable losses.
Although several advances have been made in the health system in Brazil, there is a gap in management concerning the structural and organizational aspects of vaccination rooms, which reinforces the importance of systematic supervision by the higher hierarchical levels of the health system 11 . Considering the importance of immunization in the process of preventing diseases and improving the health of the population and the fact that vaccine losses burden an important amount of public resources, it is relevant to analyze this problem in order to know the determinants of the problem and suggest measures that can act directly in preventing these losses.
Thus, the objective of the study was to analyze the vaccine loss- where there are 370 vaccination rooms, managed, at the regional level, by a regulation and distribution center, located in the Regional Health Superintendence (Superintendência Regional de Saúde -SRS) 12 . All municipalities in the studied region were included in the study.
The data were obtained using the forms used by SRS, to assess losses of immunobiologicals due to temperature changes.

RESULTS
During the study period, 138 forms were produced, but not all were located. Only 120 (87%) were found. The year with more occurrences (60, corresponding to 50%) was 2016.
Among the 54 municipalities belonging to the Health Region, there were occurrences in 27 of them. The municipalities that most notified were M1 with 28 occurrences (23.3%) and M2 with 22 (18.3%) ( Table 1). The municipalities that had less than five occurrences were classified as "Others" in order to optimize the table.    The monetary values of certain special immunobiologicals and also, the values detailed by lost immunobiologicals, were not made available, preventing a real valuation of losses.

DISCUSSION
To maintain vaccine coverage, it is essential to ensure the safety of vaccines 13 . Although most of the losses were attributed to the lack of electricity, considerable losses were observed due to equipment failures and professional error. These two events could have been avoided had there been greater attention and monitoring of equipment and temperatures.
Regarding human failures, experts emphasize the constant need for permanent education for professionals who work in vaccination rooms, since it was evident the direct influence of this professional gap leading to the loss of vaccines 14,15 .
Thus, nurses should have greater participation in vaccination rooms, to manage and supervise the adequate conservation of the immunobiologicals that will be administered, and to evaluate the performance of the nursing team, to have more participatory and targeted monitoring for the improvement of the team, aiming at the quality of assistance.
Only half of the municipalities in the region reported changes in the temperature of immunobiologicals during the period stud- with more than five forms of gauges, which seem to fulfill the function properly. There was only one occurrence that pointed out problems with the existing gauges, which is opposed by another study, which states that many digital thermometers, or extension cables, that measure the current, maximum and minimum temperatures of vaccine rooms were apparently damaged 20 .   16,21,22 .
In relation to vaccines placed under suspicion, most of them were due to equipment failure, which was not maintaining the ideal temperature. Immunobiologicals exposed to inappropriate equipment, which pose a risk of temperature changes, are constantly placed under suspicion. One of the causes of this problem is the option of many municipalities to carry out reparative maintenance instead of preventive maintenance, as evidenced in another study related to the quality of conservation and storage of immunobiologicals 23 .
In cases of temperature variations outside the ideal standard, it is recommended to immediately report what happened to the municipal and regional reference bodies, to fill out and send a specific form for the evaluation of immunobiologicals under suspicion and to keep the vaccines at temperatures between +2 and +8ºC until the final pronouncement 4  With vaccines that were rendered useless, 111,145 doses were lost. As also found in a study in which the loss of immunobiologicals due to preventable causes was 3,437,552 doses 1 .
Such doses could be being used for the immunization of the population and reinforcing the prevention of diseases preventable by the basic vaccination schedule and some special ones available in the system.
A limiting factor of the study was the existence of records from the last three years only, since the previous ones were discarded without an informed reason. In addition, when data is shared between the involved bodies, some data relating to the number of vaccines placed under suspicion is lost.
With the realization of the study it can be identified that among the determining factors for the loss of immunobiologicals, what stood out the most was the lack of electricity in the city, which could be mitigated with the use of nobreaks in the refrigerators, as recommended by the CF, or by sending smaller amounts of immunobiologicals to the municipalities most affected by this problem. The failure in the equipment also occupied a prominent place, which reinforces, according to the CF, that the use of domestic refrigerators is not the most suitable for the storage of immunobiologicals. The analysis of the losses also showed that the thermometers are widely used, however the temperatures fluctuate well beyond the ideal temperature, making it possible to inquire about the discontinuity of the care of the nursing staff in the care of the vaccine rooms.
Although many studies highlight technical losses, this study shows that the index of physical losses from vaccines, due to temperature changes, in the studied region was relevant, which burden SUS, as the value could be used for other important purposes in prevention comorbidities. Among the factors already mentioned, it should be highlighted the non-preventive maintenance of the equipment, together with the professional's mistakes, which could have been avoided.
The importance of using and correctly filling out the Forms for the evaluation of immunobiologicals under suspicion also needs to be stressed for better monitoring of the PNI, and in order to ensure that the immunobiologicals that are offered to the population preserve their immunogenic capacity. Therefore, it is suggested the adoption of some management behaviors of the Ministry of Health, together with the state and regional health, which can help in reducing these losses, such as the reevaluation of the calculation of the quotas for sending immunobiologicals, so that excess doses are sent. It is also necessary to analyze the question of the response time of the regional offices for the health units, in relation to vaccines placed under suspicion, to avoid possible losses due to validity, since this analysis must be taken as a priority.
However, it is hoped that this study can stimulate a process of reflection to health professionals about the importance of supervision, monitoring and evaluation of activities related to CF, aiming to achieve greater effectiveness in the conservation and manipulation of immunobiologicals.