Journal of School of Public Health and

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Background and aim: In this study the cytotoxicity to human epithelial lung cells of single-walled carbon nanotubes, multi-walled carbon nanotubes and chrysotile was compared based on the following cytotoxicity indices: no observable adverse effect concentration (NOAEC), inhibitory concentration 50 (IC50), and Total Lethal Concentration (TLC).

Materials and Methods: Human epithelial lung cells were exposed to different concentrations (1 to 1500 µg/ml) of carbon nanotubes and chrysotile for 6 and 24 hours. Cytotoxicity was assessed using the MTT assay. NOAEC, IC50, and TLC idices were determined by probit analysis.

Results: The results showed statistically significant correlations (p<0.001) between cytoxicity and exposure concentration in the case of all the three compounds. The NOAEC and IC50 indices were lowest for the multi-walled carbon nanotubes, while the single-walled carbon nanotubes showed the lowest TLC index.

Conclusion: Cytotoxicity of multi-walled carbon nanotubes at low concentrations was higher than that of single-walled carbon nanotubes and chrysotile. This would mean that exposure to this compound occurs at low concentrations. Thus, cytotoxicity of multi-walled carbon nanotubes is a cause for concern. It can be concluded, then, that, like chrysotile fibers, crabon nanotubes are also considerably toxic to human epithelial lung cells.

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Background and Aim: The most important single determinant of the quality of life of the elderly is health. Studies have shown that health declines with age. Because of high vulnerablity of the elderly due to many problems, they need particular attention and self-care programs for their health promotion. The objective of this study was to assess the quality of life of elderly clients under coverage of the Southern Tehran Health Center and determine the effects of a self-care program on it.

Materials and Methods: This was a controlled interventional study conducted in 2010-2011. A total of 132 elderly clients (52 in the intervention, and 80 in the control, group) were selected by randomised cluster sampling from 5 Health Care Centers in Southern Tehran. A 3-month educational program was prepared with contents based on books published by the Ministry of Health and Medical Education and implemented. The quality of life was assessed in both groups at the beginning and 2 months after the intervention using a short questionnaire (sf36). Data were collected through a structured interview (demographic characterstics) and analyzed using descriptive and analytical statistical tests.

Results: The mean quality-of-life score of the experimental group increased after education the mean score of physical domain of the quality of life increased from 52.75 in 66.11 and that of the emotional domain from 53.61 to 70.85. The scores of different domains of quality of life of the control subjects did not change significantly.

Conclusion: The findings show that a self-care educational program can have a positive affect on quality of life of the elderly.

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Background and Aim: Becoming to an adult who is sexually healthy is one of the key developmental activities for adolescents. sexual health is included of sexual development and reproductive health and also the ability to create and maintain good interpersonal relationships, are valued for their body, Respectful engagement with both sexes in correct method and expressed a desire, love and intimacy based on personal and stable social values.
Materials and Methods: In this study, using key words adolescence, sexual behavior, sexual risk behavior and sexual health and peers, related studies from 1370 to 1390 in IranMedex, Irandoc, Medlib, SID and Google scholar were investigated.
Results: Factors and challenges are associated with adolescent sexual health can be categorized into the following 4 themes (12 sub themes): Religious beliefs and spirituality (abstinence) lack of sexual education (false beliefs and knowledge about sexual function adolescents' attitudes toward risky behavior and sexual relations information sources of adolescents skills for "say no") community and youth issues(gender differences relationships with peers monitoring and control by the family communication challenges between teen and parents socioeconomical factors Centers for reproductive health services to adolescents) adolescents sexual relationship outcomes (catching sexually transmitted diseases probability).
Conclusion: In some areas, including relationships between parents with children, gender differences, attitudes and sexual behavior and the influence of peers, Studies conducted in our country is well. But in areas such as spirituality and religious beliefs, self-control, prevalence of sexually transmitted diseases and AIDS, life skills in adolescents and intervention strategies to promote sexual health of adolescents there are a great gap.

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 Background and Aim: Definition of World Health Organization 1948 for Health includes social domain which two other domains of health, physical and mental, have counter effects on it. Quantity and quality of an individual relation to community in order to improve population welfare is a definition for social health. Social capital and security improvement and reduction of impoverishment and inequity is the impact of this relation and it's opposite side is increasing social problems. In this article, by reviewing social health situation of Iranian community and analysis of it's determinants, improvement strategies have been provided and role of Ministry of Health and Medical Education(MOHME) proposed.

 Materials and Methods : This is a descriptive and analytic study A conceptual framework were described based on a nationally committed definition of social health and used for description and analysis. Secondary data of reviewing existing research and documents were utilized for situational analysis Focus group discussion of steering/stakeholder committee members and review of the best evidences and international experiences made analysis and proposed interventions.

  Results: The evidences show that average increasing rate of social problems during recent years is 15% annually. Albeit, it is not possible to draw the increasing or decreasing trend of social health indices precisely since past 2 decades due to the lake of surveillance system. Several social problem reduction and social health improvement interventions are running by organization but, inadequate sensitivity of responsible persons, not to evaluate the current interventions, inadequate utilization and coverage of population from primary level preventive services, inappropriate selection of essential interventions, allocation of most available resources to tertiary level of prevention(after harm services), weakness of activity implementation system and intersectoral collaboration for executing interventions, disintegration of social health related financial resources and inadequate sensitivity and competencies of people in combating to social problems and risks are obstacle to effective interventions in improving social health indices. Economical, political, international and technological big changes should be added to these reasons.

  Conclusion: Social health progress will not be achieved without intersecotral collaboration Improvement of existing situation is not under duties and responsibilities of MOHME, so proposed direction including vision, strategic objectives and interventions, for social health should be implemented partially by MOHME Remaining parts required advocacy to be done by other sectors. It is essential that the proposed program be approved in health policy council of MOHME for implementation of this direction and achieving to it's objectives and then be approved by health and food security high council and social council of country after that the intersectoral collaboration agreements of social health improvement should be supervised deeply.

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  Background and Aim: Women perceive menopause differently. Beside biological changes, women experience menopause based on the cultural scenarios. The qualitative research presented here is about how Iranian women perceive menopause within cultural scenarios.

  Materials and Methods : Data was collected during 4 focus group sessions and 6 individual in-depth interviews of women aged 40 years and older. Informants were selected from the Tehran University of Medical Sciences. The sessions were facilitated by using a semi-structured inventory focus group. Content analysis was adopted using combined free and analytical coding to reduce data, to extract meanings, to categorize domains and to obtain themes .

  Results: We categorized our findings into four main domains: gender role, the changes in socialization, social interactions and supporting resources. Descriptions of the later domain are going to be reported in subsequent manuscript.

  Conclusion: The women's understandings of menopause are shaped based on the specific cultural scenarios. Menopause recognized as a factor which changes women’s life line. Meanings as 'Loosing femininity' and 'changes in women's roles in the community' describe women's gender role, social interactions and changes in the socialization throughout the menopause years. The women’s misconceptions, accumulated myths, and ignorance about femininity were evidenced based on narratives. The majority of women raised ‘role change’ as an important determinant in social interactions. Gender role changes as well as women's socialization patterns have forced women to accept loosing femininity as a reality. Developing comprehensive and culturally sensitive health services to address women's needs in the climacteric years is suggested .

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  Background and Aim: Malaria remains an important vector-borne disease globally and is a threat for human life. Forty percent of the world’s populations who are living in low-income countries are at risk of malaria. The disease exists in Iran and caused economic and social damages. As result of malaria control program that has been done during the past years, the disease is eliminated from the most parts of the country, so that it is only reporting from a small part in these years.

  Materials and Methods : During this study, all available papers, books and thesises were reviewed and articles from Iranmedex, DIS and PubMed databanks were also used. Furthermore the related reports from different sources were noted.

  The extensive studies have important information about malaria vectors. In this study the data about malaria vectors and related training courses are listed. During this study the related papers, Books and thesises which have been reviewed.

  Although efforts, surveillance system, diagnostic and treatment facilities, as well as knowledge and attitude of peoples regarding to health behavior are improved nowadays, there are significant improvements about decreasing the malaria cases. Risk of the disease exists because of population exchange and asymptomatic cases. The malaria can be studied with both public health and economical aspects. This paper represents entomological studies of malaria during 1935 by the end of 2008.

  Conclusion: our study revealed that, based on recent malaria national program, the authorities should make an emphasis on vector control monitoring, resistance management, malaria evaluation and because of weak supervision on all malaria operation at stage of elimination of malaria, accurate and careful suppersional require to reach the objective and goal of elimination.

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  Background and Aim: High fruit and vegetable intake has been introduced as one of the key factors of healthy diet to prevent chronic disease. This study attempts to explore the fruit and vegetable intake in Arak city and its relationship with demography and socio-economic factors.

  Materials and Methods : In this cross sectional study, 660 people in 18 -70 age range were selected with a two-stage cluster sampling and were interviewed for demography and socio – economic questionnaires and a 56- items semi-quantitative food frequency questionnaire to assess fruit and vegetable intake. After univariate analysis, the association of the significant variables with fruit and vegetable intake was also evaluated with multiple linear regression.

  Results: In this study, over 60 percent of subjects consumed less than the minimum recommended amount of fruit and vegetable (5 servings or 400 gr a day).The total consumption of fruit and vegetable indicated an inverse significant relationship with age (p =0.04 and β = - 0.02), and a direct significant relationship with economic status (p <0.001and β =0.10). The father's educational level (p =0.005 and β =0.38 for diploma level and p =0.03 and β =0.36 for academic education) and physical activity level (p =0.001 and β =0.03 per hour) were factors associated with fruit consumption. The gender was only associated with vegetable consumption so that women had higher consumption in this study (p =0.03 and β=0.23).

  Conclusion: The findings of this study indicate low fruit and vegetable consumption in the population under study. In this study, age, physical activity, and socioeconomic status and fathers’ education were the factors that were significantly associated with fruit and vegetable consumption.

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  Background and Aim: specific and scientific study in the field of malaria in Iran commenced simultaneouoly with establishing the Instituted of Malariology in Tehran University. Subsequently the Institute was changed to school of Public Health and Institute of Public Health. Research which this new situation resulted in increasing studies and researches in the field of malaria based on three main items as entomology and vector control, parasitology and epidemiology. Historical study of malaria prepares a worthy opportunity to remind the pioneers and those who dedicated their life for combating malaria. In this study the situation of published papers, prepared theses by Iranian researchers and specific training and fresher training courses in the filed of malaria parasitology during the last fifty years were considered.

  Materials and Methods: This study was conducted as a retrospective study based on the collecting all available data from internal and external electronic sources, papers, books, reports, theses. Moreover, some interviews were made with relevant knowledgeable individuals, in the field of malaria parasitology in Iran.

  Results: In this study 143 papers in the field of malaria parasitology were collected in Persian and English languages. Thirty five MSPH, MPH, PhD these and forty four specific courses were recorded as well.

  Conclusion: The collected data indicating the correct comprehension of Iranian researchers from importance of malaria infection and its parasitology in Iran. The facts also show that specific training and retraining of malaria microscopy played considerable role in the control of malaria in Iran.

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  Background and Aim: In many diagnostic studies, including surveying the survival of patients with gastric cancer where each individual after surgery can experience more than one type of event, and the occurrence of one type of event hinders the occurrence of other types of events, the question of competing risk is raised. For checking the effect of each covariate on the occurrence of any event and estimating the hazard function, Cox and Fine and Gray models are used. In the event that the assumptions of two models do not hold, using them will be an incorrect course of action. One way to overcome this problem is to use models that have higher flexibility.

  Materials and Methods: In this study, the demographic, clinical and therapeutic characteristics of 330 patients with gastric cancer who referred from January 1996 to April 2000 to the Cancer Institute of Iran Imam Khomeini Hospital and underwent surgery, including their type, and the time of occurrence of the first event (locoreginal replace/death) for each patient from medical records were collected and evaluated. Using this information, the cumulative hazard function of relapse of disease was plotted by means of three models Cox, Fine and Gray and the flexible one, and was checked against the observed cumulative incidence function of recurrence of disease and, finally, their performance was evaluated.

  Results: Nearly, for each event, the proportionality assumption holds for all the variables . According to the graph of cumulative incidence function for the event of interest (recurrence), it can be seen that the Cox model, has overestimated the cumulative incidence function and the curves of two other models are very similar and also similar to the observed curve. However, the cumulative incidence function of the flexible model is smoother than the others.

  Conclusion: In the competing risk framework, Cox model is not very useful in practice while it seems that the flexible model is not only a good alternative to the Fine and Gray model but will also be superior to it when the assumption of proportionality does not hold.

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  Background and Aim: Urinary Incontinence (UI) as a main health problem affects on Quality of Life negatively. UI prevalence is reported between 3-57.1% in different countries. Nevertheless, there are limited studies about probable risk factors, e.g. type and number of delivery and related disorders such as anal incontinence. This study was aimed to investigate the UI risk factors and related disorders in our society.

  Materials and Methods : A cross-sectional study was conducted on 166 women with UI and 90 healthy subjects, aged 26-70(45.3±7.9) and 20-64(38.2±8.4) years respectively. After completing a designed questionnaire, assessment of vaginal tone, Pelvic Floor Muscles'(PFM) strength and endurance carried out. Independent t-test and Pearson correlation test were used to analysis the data. Values of p<0.05 were considered to be significant.

  Results: Our data showed that the mean of age, Body Mass Index (BMI) and number of deliveries in women with UI were significantly higher than that women without UI were (P<0.05).There was a significant difference regarding to the prevalence of anal incontinence and constipation between two groups (P<0.05). Reduced vaginal tone and lower strength and endurance of PFM were seen in women with UI (P<0.05).

  Conclusions: Regarding high prevalence of some pelvic floor disorders such as constipation in incontinent women, we recommend performing further epidemiologic and etiologic investigations , also emphasis on establishing multidisciplinary approach health/therapeutic centers to provide better services to these patients.

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  Background and A im : sexual health in children is difficult subject, does not deal with it formal method. Importance of Sex education of children is accepted in the world. The aim of this paper is describing the concept of sexual health from the viewpoint of children's famil y and identification norms of child sex education and determining sex education priorities of the parent's viewpoint.

  Materials and Methods: This is qualitative study. Samples were selected by targeted method of student's parents of five regional educated o f Tehran. Data were collected by focus group interview and discussion and were analyses by subject and content analysis.

 
Results: The findings were classified in three main areas: 1) Family management 2) the role of school 3) framework of the religion an d traditions.

 

  C ONCLUSION onclusion : Most participants believed sexual health behavior in children is not health indicators. They implemented their family policies in management of Sexual behavior o f their children. In Family control was meant: restriction of sexual behavior in child as a norm. Culture of silence and connivance in management of children's behavior has become norm, because child's sexual behavior is inconsistent with traditional values of family. In identifying priorities of sexual education of children, progression interaction between home and school was known as the most deficits. They are acting their internal values in educational system of children because their conflict of values, norms and tastes difference has not been challenge. It is important and priority of parents to being prepared for the management of their children's sexual behavior .

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  Background and Aim: One of the most important problems in intensive care unit is high nursing workload. High workload may lead to increased human errors, compromised quality and safety of care, and reducing quality of working life. The purpose of this study provides valid and reliable tools to assess the mental workload of the ICU nurses and also identify inducing factors that will create workload.

  Materials and Methods: This study had two phases. 1- Determine the face validity and reliability of the NASA-TLX (to assess the workload) by Backward Translation method and Cronbach's alpha method. 2–Designing the performance obstacles and facilitators questionnaire by interview and pilot study.

  Results: Face validity and reliability of NASA-TLX method was confirmed (α=0.897). The performance obstacles and facilitators questionnaire for ICU nurses provides in 53 questions and 10 subscales. Relevancy is 97% and Clarity is 96%. Overall, 90% of nurses assessment comprehensiveness of the questionnaire was very comprehensive and comprehensive.

  Conclusion : According to the results, can be used NASA-TLX method and the performance obstacles and facilitators questionnaire to assess workload of ICU nurses.

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Background and Aim: Intersectoral Collaboration and Community Participation are two main strategies for sustaining equity in health. Based on the 4th 5years country development plan, Health and Food Security High Council(HC) as a strategy for developing intersectoral collaboration. Reviewing members' opinions of HC may show the clear way of improving intersectoral collaboration for health promotion of the population to senior officials of Ministry of Health and Medical Education. Materials and Methods: This was a descriptive and qualitative study. Information were gathered by structured interview to HC members and content analysis of the documents and gray materials related to initiation and performance of the HC since it's opening. Content analysis and adding up the interviews were done by hand after defining the main domains. Results: Most of HC members believed that the HC effectiveness is very low or low. For the 1st step, defining health priorities and then responsibilities and expectations of each organization were proposed. Organizations necessity to introduce a sustained representative, creating taskforces for deep working on the issues, regular meeting in secretariat, concurrent information sharing to the members, strengthening similar structure in provinces and giving more authority to them and connecting the council to the scientific committees of health elites are main improvement approaches. Conclusion: There is gap between the performance of the HC and the law makers' expectations. Implementing secretariat of HC including expertise and special working system of intersectoral collaboration will mostly cover the weakness. Defining periodical roles and expectations of organizations and capacity building of health collaborators of the ministries and organizations, and incentivizing organization which have effective contribution, will strengthen and continue the collaboration more.

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Background and Aim: Quality of life amongst people living with HIV/AIDS is affected by their experiences such as social isolation, stigmatization and discrimination. Physical, mental and social problems are common throughout their lives. Therefore, studying the quality of life of HIV-infected individuals are shortcomings in various cultural contexts. The purpose of this study was to assess the quality of life of people living with HIV/AIDS in Iran. Materials and Methods: A cross-sectional study design was used. We used convenience sampling to recruit 300 HIV-infected adults attending the Imam Khomeini Hospital consultation center for clients with risky behaviors in Tehran. To collect the data we employed the World Health Organization Quality of life for HIV Brief version (WHOQOL-HIV BREF). T-test, one-way ANOVA, Pearson’s coefficient and multiple regression were used for analysis. Results: The mean ±SD age of the respondents was 34.3±7.5 years. The majority of them were males (55%) and asymptomatic (51.7%). Among the domains of quality of life, Level of independence had the highest score (13.4±3.1), and environment (12.5±2.8) and psychological (12.5±3.1) domains had the lowest. Younger's, women and employed subjects reported better quality of life for different domains of quality of life (p<0.05). Conclusion: Psychological and environment domains in quality of life were found to be adversely affected by HIV. Accurate and culturally sensitive interventions are suggested to address the patients' psychological and environmental needs.

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Background and Aim: Child abuse is a social problem that affects the lives of children. The purpose of this study was to design a valid and reliable Persian questionnaire to measure the status of child abuse. Materials and Methods: Content validity was measured with search of relevant electronic databanks, preparation of the first draft of the questionnaire and determinant of its relevancy and clarity. Reliability was measured with Cronbach’s alpha, and repeatability was measured with intra cluster correlation through test-retest with two weeks interval. Results: The mean of clarity and relevancy of the tool were 80.36% and 92.5%, respectively, and rang of these two measure were 90.14 - 97.2, also. The average of intra cluster correlation (ICC) and Cronbach’s alpha were 0.95 and 0.92, respectively. Conclusion: The new tool has acceptable validity and reliability and is suitable for child abuse studies in Iran.

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  Background and Aim: The objective of this study was to determine factors associated with time to relapse and, thus, retention time, of a cohort of opioid-dependents under methadone maintenance treatment, using survival models, in the Iranian National Center for Addiction Studies (INCAS).

  Materials and Methods: A total of 198 opioid-dependent clients participating in the Methadone Maintenance Treatment Program, implemented by INCAS between April 2007 and March 2011, were included in the study. A Cox proportional hazard (PH) model was applied to determine predictors of relapse time among the patients.

  Results: The data showed that 86 clients relapsed into drug use during the treatment program. The proportional hazard assumption was satisfied according to the goodness of fit test showing that Cox proportional hazard model was appropriate. Estimates of the PH model indicated that an increase of 1mg in the methadone dosage could lead to a decrease of 0.15 in hazard ratio and an increase in the length of treatment (p<0.001). Predictors for raising the probability of drug relapse included suffering from mental disorders (compared to mentally healthy: hazard ratio = 2.29, p<0.001), being a poly-substance user (compared to mono-substance users: hazard ratio = 4.80, p<0.001), and having retention experience in the past (compared to those with no previous therapy: hazard ratio = 1.90, p<0.001). Other variables entered in the model, including social and demographic variables, had no statistically significant effect on hazard ratio.

  Conclusions: Although higher methadone dosages are associated with a longer time to relapse, we recommend highly to pay special attention to providing more therapeutic and consultive services to mental health patients, poly-substance users, and individuals with a past therapy record.

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  Background and Aim: Physical inactivity is one of the 10 leading causes of mortality and disability. This study aimed to investigate the effect of e-learning on physical activity and body mass index (BMI) of female-employees.

Materials and Methods: In this semi-experimental interventional study, 120 female-employees of Tehran University of Medical Sciences were selected randomly and assigned to a case or control group. Data were collected using a demographic and an international physical activity questionnaire. Pre-test and post-test questionnaires were completed by the case and control subjects prior to, and 2 months after the final phase of, the intervention. The intervention included virtual education through short message service (SMS), email messages or messages via intanet, and educational films for a period of 16 weeks. SPSS-17 was used to analyze the data, the statistical tests being Chi-square, independent and paired-t, and Fisher's exact tests.

  Results: The mean age of the participants was 41 and 39 years in the case and control group, respectively. Most of them held a bachelor's degree and were married with 1 or 2 children. After the intervention, the mean score of physical activity in the intervention group increased significantly as compared with the control value (p<0.001). However, the intervention did not produce any change in the mean BMI of the case in comparison with the control group (p=0.119), although it brought about a statistically significant reduction in the initial BMI (p<0.001).

  Conclusion: Web-based education, SMS and multi-media messages can increase physical activity in female-employees and might prevent illnesses caused by physical inativity.

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Background and Aim: MS is a chronic and destructive inflammatory disease with a not contradiction continuing of life but can influenced the quality of life of patients. The purpose of this study is to determine the quality of life in MS and its related factors. Materials and Methods: This cross-sectional study was performed on 172 patients admitted to the MS Society of Iran (Tehran) and convenience samplings were obtained for 10 months. Tools for data collection were MSQOL-54 and MS patients were also interviewed. Data using descriptive and Analytical tests such as multiple regression were analyzed. Results: The mean age of patients was 34/8 ± 9/6 years. Analysis of 14 sub-domains of quality of life questionnaire showed that the highest average score in the domain of quality of life was social functioning (71/7 ± 21) and the least was role limitations due to physical problems (44/2 ± 39/4). Results of multivariate regression models shown that between age has an significant inverse relationship to domain of physical combined and only variable significant on the combined domain of psychological – psychiatric, Area residential Variable was (p.value 0/001). Conclusions: The study shows that demographic variables medical and economic factors influence the quality of life of patients with multiple sclerosis. Identify the factors related to the quality of life of these patients can be helpful in predicting quality of life. The variables influence on the quality of life for MS patients must be targeted in designing effective intervention programs to improve their quality of life.

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Background and Aim: This study aimed gender variations about adolescents' health-related quality of life. Materials and Methods: A cross-sectional study was performed on four hundred students selected by a Stratified random sampling. Two-way analysis of variance was used for the analysis of total health-related quality of life scores among boys and girls in terms of demographic factors. Data analysis was conducted with software SPSS 18 and LISREL8.8 programs. Results: There were important differences in health-related quality of life total score between boys and girls in relevance rank of birth, level of education and BMI. Although, these differences weren't statistically significant (p>0.05), Girls’ reports were higher compared to boys except for the emotional functioning subscale. Conclusions: Teachers and parents should make great efforts for meet the requirements and difficulties of emotional and behavioral in adolescent girls. It is Necessary to execute coping mechanisms by the training consultants to minimize stress and anxiety for the mother to be.

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Background and Aim: Expanded program on immunization is one of the strategic universally accepted methods for control of childhood diseases including poliomyelitis. Oral Polio Vaccine (OPV) which consists of live attenuated poliovirus is considered as appropriate and most convenient tool for nation-wide vaccination. Polio virus is sensitive to heat, so OPV should be kept frozen and transferred to vaccination centers under cold chain conditions. Thermo-stability of vaccine during transportation is very important. Potency test is used to evaluate the quality and stability of vaccine. This is the first documentated study on evaluation of OPV potency kept out of cold chain conditions in Iran. Materials and Methods: To study the effects of time and temperature on potency of polio vaccine, vaccine vials were exposed to 24°C (room temperature) and 37°C (average temperature in tropical regions) for one to seven days. Vaccine potency evaluation was performed according to World Health Organization protocol. Results: It can be inferred from comparison of the results of this study with the international standards that OPV is stable at 37◦C for only one day, but if it is exposed to room temperature for 4-5 days, serotypes 1 and 2 remain unaltered but serotype 3 will lose its potency to a great extent. Conclusions: Although Polio viruses are relatively resistant to environmental conditions, their sensitivity to heat is the reason to transport the vaccine, which contains live attenuated virus, under cold chain conditions. This will prevent the titer of the vaccine virus to decrease. Vaccine stored at temperature below 4°C is preferred, otherwise the vaccine kept at room temperature (24°C) is useable for 4-5 days, and at 37◦C the vaccine is potent only for one day.