Showing 25 results for Control
R Chaman , M Yunesian , B Golestan , K Holakouie Naieni ,
Volume 3, Issue 3 (2-2008)
Abstract
Background and Objectives: A pregnancy can be considered high-risk if there are conditions that put the mother or the baby at higher-than-average risk of morbidity or mortality. Neonatal mortality rate is one of the most important indices of children's health status. The present study was conducted to evaluate the effects of high-risk states on neonatal mortality.
Methods: We performed a nested case-control study in the rural areas of Kohgiluyeh and Boyerahmad province. Within the study cohort, 97 cases and 97 controls were selected by a risk-set sampling method. Data were analyzed with univariate and multivariate conditional logistic regression models.
Results: Neonatal mortality was shown to increase significantly in high-risk pregnancies. There were no substantial differences between crude odds ratios and those adjusted for the presence of other risk factors (crude odds ratio decreased from 5.5 to an adjusted figure of 3.25 for pregnancies with one risk factor and from 5.21 to adjusted level of 4.80 for pregnancies with more than one risk factor).
Conclusions: High-risk pregnancies need great attention in family health and prenatal care programs, especially in remote rural areas. Within our rural health network there are potential cohorts for use in nested case-control studies, especially in the evaluation of neonatal mortality risk factors.
M Qorbani, M Yunesian,
Volume 4, Issue 1 (4-2008)
Abstract
The case-crossover design was developed in the early 1990s to study the effects of transient, short-term exposures on the risk of acute events such as myocardial infarction. To estimate relative risk, the exposure frequency during a period just before outcome onset (hazard period) is compared with exposure frequency during control time(s) in that person rather than in a control. One or more "control times" are supplied by each of the cases themselves to control for confounding by constant characteristics and self-confounding between the trigger's acute and chronic effects.
In the analysis of case-crossover studies, exposure frequency in the hazard period is compared with the control period or the individual's usual frequency of exposure. The design has been used frequently for heart diseases, injuries and air pollution epidemiology. This review article looks at published case-crossover studies and is intended to help the reader gain a better understanding of the strengths and limitations of the case-crossover design in studying the epidemiology of injuries and air pollution.
F Rakhshani, Mt Heidari, S Barati,
Volume 4, Issue 3 (3-2009)
Abstract
Background and Objectives: Injury by sharp instruments and needles are major occupational health hazard for healthcare workers. This study was conducted to determine the prevalence rate and causes of injuries due to needle stick in healthcare workers in Zahedan University of Medical Sciences.
Methods: In a cross-sectional study, 231 healthcare workers of university hospitals of Zahedan University of Medical Sciences were selected at random in 2007. Data were collected through questionnaire and were analyzed by SPSS 13.
Results: From all cases 77.1% were female 56.4% of them were expert, and 50.7% were nurses. Their mean age were 34±8.1 years. Needle stick prevalence was 64.9% during the whole history of career, and 57.2% of them had experiences of needle stick more than twice. Most cases of injuries were related to using needle 55.4%, and they were mostly prone to injury during injection and phlebotomy, 55.6%. The multivariate regression analysis showed that injury due to sharp instruments in university graduates was 60% less compared to those with high school or less, and the injury risk increases 5% in each year of increase in working experience.
Conclusions: The findings of this study highlight the importance of training and preventive measures in healthcare centers particularly among high risk group.
N Esmailnasab, A Afkhamzadeh, A Ebrahimi ,
Volume 6, Issue 1 (6-2010)
Abstract
Background & Objectives: According on surveys in Iran more than two million persons have non insulin diabetes mellitus. There are evidences that good glycemic control reduces the risk of diabetic complications. This study was designed to evaluat the glycemic control by using fasting blood sugar and hemoglobin A1C estimation and their relation with some variables.
Methods: This cross sectional study carried out on 411 people with type 2 diabetes who referred to Tawhid diabetes center in Sanandaj. Demographic and other variables were gathered by a deigned questionnaire. Univariate analysis and multivariate analysis (logistic regression) were used.
Results: In Univariate analysis FBS showed a significant relationship with education, job and referral style and HgA1c was statistically significant with sex, age, education, and job. But logistic regression showed other
Results: in final model FBS and HgA1c were associated with body mass index and referral style and HgA1c had association with only body mass index and referral style. Correlation confidence between FBS and glycated hemoglobin was (r = 0.54).
Conclusions: It is concluded that BMI and referral style have association with diabetes control.
K Holakouie Naieni, A Ostovar, A Danesh, S Sadjedinejad, L Ghalichee, Gh Moradi, Ma Mansournia, Ss Hashemi Nazari,
Volume 6, Issue 2 (9-2010)
Abstract
Background and objective: The nested case-control study has become popular as an efficient alternative to the full-cohort design. This study compares the results of a nested case-control analysis approach with the full cohort analysis.
Methods: A cohort of 276 subjects (new cases from a TB registry) was used for this study. Cox Regression model was used for the full cohort analysis. In order to do the nested case-control analysis, for each death, three random controls were selected from those who did not suffer from the outcome at the time of the outcome took place. Case control data was analyzed by the conditional logistic regression model.
Results: Results from both cohort and nested case-control analyses show that treatment group is the only variable that affects on the outcome. Gender, place of residence, and age has no effect on the outcome. For binary exposure variables with trivial effects (e.g. Gender and place of residence), the relative efficiency of nested case-control study design is approximately 75%.
Conclusion: Results of this study show that nested case-control study is not only an easy and cost-effective method for data analysis but also is as robust as cohort analysis in rate ratio and its variance estimation.
R Rafat, Ar Dorosty, Mr Eshragian, A Rezazadeh,
Volume 7, Issue 3 (12-2011)
Abstract
Background & Objectives: Increasing in prevalence of juvenile myopia in recent decades in eastern and western countries, especially in urban elementary school children, suggests that changing in early life style may play an important role in development of myopia. Our aim was to determine the relationships between myopia and overweight in elementary school children of Eslamshahr a city near Tehran, Iran
Methods: In a case control study, 240 new myopic primary school children (grade 2-4) identified as cases and 240 children without myopia in the same schools enrolled as control group.
Anthropometric information was completed from schools’. Other information about pre-entrancing to school was collected by interviewing their parents. Children having a Body mass index BMI>=85th CDC2000 percentile were identified as overweight. Adjusted odds ratio for overweight was estimated after adjusting other potential risk factors.
Results:
Of total 53.3% were girls. 23.8% of children in case group and 10.1% of them in control group were categorized in overweight group. After adjusting for other potential risk factors (family history, breast milk intake, near works, mother`s job and financial position) being overweight was independently associated to myopia
(OR: 3.10, 95% CI: 1.9-5.03).
Conclusion: It is concluded that overweight in children in preschool age, is independently associated with increased risk of myopia in primary school children. Therefore health promotion programs in order to change of the life style in this group of children should be considered.
M Mohammady, N Toghian Chaharsougi , S Abdoli,
Volume 9, Issue 3 (2-2014)
Abstract
Background & Objectives: Randomized controlled trials are the most reliable type of study to be able to compare different interventions in scientific research. The introduction of bias into the design and conduct of randomized controlled trials can seriously affect the accuracy of the results and led to the results be invalid. The aim of this study was to assess the bias in randomized controlled trials published in Iranian nursing and midwifery journals.
Methods: We searched all published articles in eight professional nursing and midwifery Iranian journals in 2010. Risk of bias in RCTs was assessed using of Cochrane group risk of bias standard tool by two reviewers independently.
Results: After reviewing the eight journals, 68 randomized controlled trials were retrieved. The majority of studies had unclear or high risk of bias. Random sequence generation in 22%, concealment allocation in 4.5%, blinding in 22%, incomplete outcome data in the 35.3%, selective outcome reporting in 51.5%, and other bias in 36.7% of the studies were in low risk of bias.
Conclusion: A large proportion of the studies had high or unclear risk of bias. It was considerable that none reporting bias led to uncertainty reader from study quality. Bias might significantly affect the internal validity of the studies results therefore in interpretation of the findings of these studies caution should be taken.
H Akbarein, Ar Bahonar, S Bokaie, N Mosavar, A Rahimi- Foroushani , H Sharifi, As Makenali, Nd Rokni, B Marhamati- Khameneh , S Broumanfar,
Volume 10, Issue 3 (12-2014)
Abstract
Background & Objectives: Bovine Tuberculosis (BTB) is one of the most important zoonoses. Mycobacterium bovis is the responsible agent of BTB in the cattle. The current study was conducted to investigate the determination factors of BTB in dairy farms covered by the tuberculin screening test.
Methods: A herd level case- control study was carried out in 124 (62 cases & 62 controls) dairy farms in the provinces of Tehran, Alborz, Hamedan, Isfahan, Qazvin, Qom, Mazandaran and Semnan. The control farms were individually matched with case farms by farm capacity and distance. Statistical analyses were done by Stata 11.2 using conditional logistic regression.
Results: Proper management of manure (OR=0.12 95% CI: 0.03-0.49), regular flaming of stalls (OR= 0.21 95% CI: 0.04-0.92) and complete fencing around the farm (OR= 0.17 95% CI: 0.03-0.81) decreased while the presence of rodents (rat) (OR= 4.90 95% CI: 1.04-23.01) increased the risk of infection. The interaction among these variables was not statistically significant
Conclusion: According to the results, there is an essential need to pay more attention to rodent control in farms.
F Moghaddas, F Yousefi , F Bagheri, M Mohammadi , F Mahdian Arefi , A Beikmohammadi, Mh Emamian,
Volume 11, Issue 2 (9-2015)
Abstract
Background & Objectives: Urinary calculi are a common problem worldwide. The pattern of fluid consumption in healthy people and patients with renal calculi is not totally clear. The aim of this study was to determine the association between the amount of fluids intake and urinary calculi.
Methods: In this case-control study, cases were the patients with urinary calculi admitted to Emam-Hossein Hospital, Shahroud, Iran. The controls were selected among the patients admitted to other wards of the hospital except for dialysis and ICU wards. The association between independent variables and urinary calculi was investigated using logistic regression analysis.
Results: A total of 127 people (60 cases and 67 controls) participated in this study. The mean age of the participants was 44.6 years (SD = 1.7). The mean intake of tea, natural juice, alcohol free beer, and total fluid intake were higher in cases compare to controls. In participants with a negative history of urinary calculi, the total intake of fluid (P=0.021) and natural juice (P=0.006) was higher in cases. The male gender (OR=3.2), higher BMI (OR=1.2), and a positive family history of urinary calculi (OR=3.5) were associated with renal calculi in a multivariate logistic regression model, while the milk intake (OR=0.995) was a protective factor in this model.
Conclusion: Milk intake is a protective factor and the male gender, higher BMI and a positive family history are the risk factors for urinary calculi.
V Montazeri, F Jafarpour Sadegh , S Hosseinpour, Hr Mirzaei, E Akbari, M Ehsani, S Akbari, N Asadi, M Mahmoudinezhad, E Mirtaheri, Z Sanaat, S Pirouzpanah,
Volume 12, Issue 1 (6-2016)
Abstract
Background and Objectives: Reproductive factors are in close relationship with breast carcinogenesis. This matched case-control study was conducted to study the association of reproductive risk factors with the risk of breast cancer (BC) among women in Tehran and northwest of Iran.
Methods: This hospital-based case-control study was performed on a total of 432 patients diagnosed with BC with confirmed histopathology who were recruited from hospitals affiliated with Shahid Beheshti and Tabriz University of Medical Sciences between 2007 and 2012, and 543 regionally matched controls without a prior history of BC.
Results: The average number of pregnancy and breast-fed children were significantly higher in cases than controls (P<0.01). The duration of breast-feeding was longer in patients (18.0±8.4 months) than controls (16.0±9.1; P<0.001). Most of the patients were diagnosed with BC above the age of 48 years old which was higher than the mean age of the recruited matched controls. Older age was associated with a 3.87 higher risks of BC development (95% CI: 2.94-5.10). The higher frequency of lactation in patients was significantly associated with the elevated risk (OR=2.22, 95% CI 1.62-3.04). The duration of breast-feeding within14-24 months was correlated with OR=0.52 to protect BC development during the reproductive age
(<48 years) (95% CI: 0.32-0.86).
Conclusion: High frequency of pregnancy, lactation, and older ages at first pregnancy are associated with the risk of BC, while older age at puberty, menopause, and longer duration of breast-feeding (age above 48 years) have inverse associations with the risk of BC.
F Bagheri Amiri , Ar Bahonar, E Mostafavi, Ma Mansournia, N Rasouli , Mh Fallah Mehrabadi, D Abdollahi, Sholepash,
Volume 12, Issue 1 (6-2016)
Abstract
Background and Objectives: Foot-and-mouth disease (FMD) is one of major contagious animal. The purpose of this study was to evaluate the determinants associated with FMD occurrence in farms.
Methods: A case- control study was carried out in cattle farms. The cases were farms with new reports of FMD and controls were units without any report of FMD in last 6 month. For assessing the risk factors, a researcher- made questionnaire was used. Statistical analyses were done with SPSS version 16 using the logistic regression test.
Results: Purchase of new livestock [OR: 14.69 (CI95%: 4.29, 50.36)] and passing migratory livestock [OR: 13.32 (CI 95%: 1.74, 101.87) were identified as the risk factors of the disease. Visiting the farm by the vaccinator in last 2 weeks [OR: 0.17 (CI 95%: 0.05, 0.63)] and buying new livestock from the same village/ city where the farm is located [OR: 0.16 (CI 95%: 0.04, 0.58)] were considered as protective factors.
Conclusion: Considering the role of infected livestock in the country, the most important steps for effective preventation are: areadherence to biosecurity as well as quarantining new purchased animals, and informing and training farmers to not purchase new animals from farms that are located in the infected areas and around the times of outbreak.
K Holakouie Naieni , Ma Mansournia, Mh Panahi, A Elduma, Sh Nematollahi ,
Volume 12, Issue 3 (10-2016)
Abstract
Case-Cohort and nested case-control designs are the most well-known and cost-effective derivatives of prospective studies. Due to the popularity of these designs in recent years, the aim of this study is to provide a comprehensive and up-to-date description of them with respect to methodological issues such as sampling scheme, effect measure estimation, and analysis strategies. Overall, random sampling of controls in case-cohort and matching for time in nested design are considered their hallmarks. Eventually, decision on a better design depends on study objectives, sub-cohort selection, case and control determination, and method of data collection. It should be kept in mind that any particular study requires unique elaboration and delicate examination to choose from the designs.
Z Torabi, Sh Nematollahi, E Ahmadnezhad, K Holakoie Naieni ,
Volume 14, Issue 2 (9-2018)
Abstract
Background and Objectives: Epidemics of diarrhea caused by contaminated food and water occur frequently worldwide, especially in developing countries. The aim of this study was to identify the factors contributing to the development and spread of diarrhea epidemics caused by Shigella flexneri in Isfahan in the spring of 2015.
Methods: Following the first reports and activation of the surveillance system, a matched case-control study was conducted in 360 cases with diarrhea and 360 controls. Data were gathered using a questionnaire, and conditional logistic regression was used to provide adjusted odds ratios and 95% confidence intervals.
Results: Consumption of contaminated fresh vegetable (OR=4.50, 95% CI=2.88-7.01) was the source of the epidemic. Contact with similar patients (OR=7.19, 95% CI=4.26-12.12), presence of similar patients in the family (OR=33.2, 95% CI=13.64-80.82), food consumption on special events (party, wedding ceremony, funeral, etc.) (OR=1.67, 95% CI=1.06-2.62), being a government employee (OR=3.08, 95% CI=1.64-5.78) and being illiterate (OR=2.91, 95% CI=1.10-7.67) were the risk factors of the spread of the epidemic.
Conclusion: In this study, consumption of fresh vegetable contaminated with Shigella flexneri was the source of the infection. According to the Epidemic Management Team, contamination occurred due to non-standard wastewater irrigation of agricultural lands. Therefore, it is important to consider the standards of agricultural production and compilation of a comprehensive program to improve the status of the wastewater purification system in the environmental sciences by the relevant organizations to prevent diarrhea epidemics.
B Moatamedizadeh, H Ansari, A Payandeh, Sm Tabatabae, A Ramazanpouramirdehi,
Volume 16, Issue 1 (6-2020)
Abstract
Background and Objectives: In addition to effective treatment, tuberculosis recurrence is a very important challenge regarding the treatment of this infection. This study was conducted to evaluate the risk factors associated with tuberculosis recurrence.
Methods: In this nested case-control study, 202 tuberculosis patients with recurrence and 202 matched controls in terms of age, sex and place of residence were studied. The cases and controls were selected from a cohort of tuberculosis patients in Sistan and Baluchestan province between 2011 and 2018. The data were collected using interviews and patients’ records. The independent t-test, chi-square and multiple conditional logistic regression were used to analyze the data.
Results: The drug abuse history (OR=6.1), 3+ smear positive (OR=3.03), chest X-ray suggestive of tuberculosis (OR=4.9), drug resistance (OR=7.3), low socioeconomic status (OR=3.9), weight loss (OR=3.1), chest pain (OR=3.2), history of digestive disease (OR=22.1), smoking (OR=6.1), and imprisonment (OR=3.7) significantly increased the chance of recurrence among tuberculosis patients (p<0.05). On the other hand, the chance of recurrence was significantly lower in patients with coughs (OR=0.29) and a small family size (OR=0.28).
Conclusion: According to the results, tobacco use, drug use, low socio-economic status, life conditions, and disease conditions are the most important determinants of tuberculosis recurrence. In general, epidemiologic factors related to tuberculosis recurrence are not similar in different regions; therefore, educational programs for patients and their families and prevention methods should be considered based on related factors in different regions.
M Karami, A Doosty Irani, Sj Battaei, L Rafati, M Javaheri, M Kheir Andish , M Farhadi, M Hashemi, K Mozafari, A Akhlagh, M Shojaeian, Ar Maleki, R Rostam Abadi , Sh Torkshavand, M Khodabakhshi,
Volume 16, Issue 3 (11-2020)
Abstract
Background and Objectives: Water and foodborne diseases are major causes of mortality worldwide. The aim of this study was to investigate the factors affecting an gastroenteritis outbreak in Hamadan county in summer of 2019.
Methods: This study was performed based on the outbreak investigation process. After producing hypotheses based on preliminary field studies, a case-control study was conducted on 45 cases and 45 controls to investigate the factors associated with the outbreak. New cases of the disease were included according to the case definition. A logistic regression model was used to investigate potential risk factors.
Results: A total of 171 people were affected in this outbreak from 25 June 2019 to 01 July 2019. The at-risk population in this outbreak was 3410 individuals. The attack rate was 5.1%. Abdominal pain, vomiting, and nausea were the most common symptoms with a prevalence of 77.8%, 73.3% and 68.9%, respectively. The results of the case-control study showed that the consumption of tap and spring/well water increased the odds of disease by 4.63 and 4.13 times compared to boiled water, although these relationships were not statistically significant. The odds of diseases were significantly lower in people aged 30-45 years and 46-85 years compared people aged 15 years old and younger.
Conclusion: Based on the results of this study, the outbreak was related to contaminated water consumption. Therefore, regular monitoring of drinking water status is very important for the local health system.
Hr Bahrami Taghanaki , E Mosa Farkhani , R Eftekhari Gol , P Bahrami Taghanaki , S Bokaei, A Taghipour, B Beygi,
Volume 16, Issue 3 (11-2020)
Abstract
Background and Objectives: Diabetes is considered as one of the most common endocrine disorders worldwide. The aim of this study was to investigate the factors associated with diabetic complications.
Methods: A case-control study was performed on the data of 70089 diabetic patients (4622 cases and 53613 controls) extracted from the SINA Electronic Health Record (SinaEHR®) in a population covered by Mashhad University of Medical Sciences in 2018. The effect of independent variables on the likelihood of diabetic complications was investigated using single-variable and multivariate logistic regression models with the control of the potential confounding effects.
Results: Using the multivariate logistic regression, the odds of developing diabetic complications were 0.35 (0.31-0.38) for living in the city, 0.73(0.67-0.79) for living in the suburbs and 0.31(0.28-0.33) for living in rural areas relative to the metropolises, 0.84 (0.78-0.91) for illiterate subjects, 0.70 (0.66-0.75) for physical activity, 1.51(1.34-1.71) for stage 1 hypertension and 1.87 (1.43-2.44) for stage 2 hypertension relative to normal blood pressure, 0.79(0.74-0.85) for uncontrolled low density lipoprotein and 1.42(1.33-1.51) for uncontrolled hemoglobin A1C.
Conclusion: Various risk factors were identified to increase the odds ratio of diabetic complications. The most important risk factors were uncontrolled glycosylated hemoglobin and stage 1 and 2 hypertension. Control of these factors can reduce the chance of diabetic complications in diabetic patients.
V Yazdi Feyzabadi , R Amiri, M Seyedi,
Volume 16, Issue 5 (3-2021)
Abstract
Background and Objectives: In the late 2019, the SARS-CoV-2 virus was identified as the cause of an outbreak of acute respiratory illness known as the COVID-19, which began to spread in the world very quickly. Preventive measures have been a significant issue in preventing the spread of COVID-19. This rapid review study was conducted to summarize selected countries' preventive policies and strategies in the East and Southeast Asia, including China, South Korea, Japan, Vietnam, and Singapore, during the COVID-19 epidemic.
Methods: In this rapid review study, the Scopus, PubMed, Embase, and Web of Science databases were searched. The keywords applied in the search strategy were primary health care, public health, prevent* and plan, policy, program, initiative, intervention, measure, and COVID-19 in addition to the name of each country. Furthermore, we searched the World Health Organization (WHO) and the United Nations Development Program (UNDP) websites to retrieve more key sources as grey literature. The relevant data were extracted from the final studies and categorized.
Results: After screening, 33 studies met the inclusion criteria. Dominant measures implemented in these countries were categorized into different categories including communication and information, physical distancing, quarantine, monitoring, and testing axes.
Conclusion: Education and information, extensive testing and screening, contact tracing, isolation of infected and suspected cases, and observance of physical distancing has been very effective in reducing Covid-19 transmission and its mortality.
Mohammad Ali Derik, Mohammad Kakavand, Shahram Mamdohi, Mojgan Navabi, Elham Goodarzi, Hamid Mokhayeri, Zaher Khazaei,
Volume 17, Issue 2 (9-2021)
Abstract
Background and Objectives: Viral hepatitis is one of the most prevalent diseases and an important underlying cause of death and disability in the world. This case-control study was conducted to investigate the outbreak of hepatitis A in Boroujerd in 2019.
Methods: This case-control study was conducted to investigate the epidemic of hepatitis A in Boroujerd in 2019. Fifty hepatitis A patients were recruited. For each patient diagnosed, two controls with no history of the disease were selected from a neighboring village. Data were collected using a demographic questionnaire as well as the results of experiments. To investigate the association between the disease and risk factors, odds ratio and 95% confidence interval were used.
Results: In this study, the odds ratios were significant for a number of risk factors including washing fruits and vegetables with a source other than tap water [OR = 3.2], washing dishes with a source other than tap water [OR = 3.7], non-sanitary toilets [OR = 8.3], using sources other than tap water when there is no tap water [OR = 4.4], being unaware of the disease and its transmission methods [OR = 4.8] and water well dug less than 15 m from the sewage well (OR = 4.1).
Conclusion: Increased public awareness and improved health status of the environment and rural sewage can preclude similar epidemics in the study area and other regions.
Sa Hashemi, K Holakoui-Naeini, Ma Mansournia, R Akrami, M Nomali, T Valadbeigi, V Mennati, Ha Adineh, Mr Taghavi, M Ghafouri, S Poorbarat, A Hoseinzadeh, M Farahdel, Mr Armat, M Haresabadi,
Volume 17, Issue 3 (12-2021)
Abstract
Background and Objectives: COVID-19 is a new disease and little information is available on its risk factors. The aim of this study was to determine the mortality risk factors in patients with COVID-19 in the northeast of Iran.
Materials and Methods: A case-control study was conducted. Patients of both sexes with a confirmed diagnosis of Covid-19 infection who died during the study were studied as the case group and patients who were in good general health and ready for discharge were studied as the control group. Data analysis was performed with the STATA software version 14 using descriptive statistics and univariate and multiple logistic regression tests.
Results: Six hundred and eleven patients were studied (27% cases and 73% controls). Multiple logistic regression analysis showed that the odds of death were 2.8 times higher in patients over 80 years compared to patients aged 50-60 years. In addition, age under 40 years reduced the odds of mortality by 85% and living in rural areas increased odds of death by 2.2 times. Cough, general fatigue, pain, nausea and vomiting increased the odds of COVID19 survival.
Conclusion: The odds of mortality were higher in elder patients with COVID-19. In addition, living in rural areas increased the odds of mortality in patients. Cough and fatigue reduced mortality; however, it is needed to address other hidden factors for sound judgment.
Fariba Zomorrodi Zare, Fatemeh Khosravi Shadmani, Roya Safari Faramani, Fatemeh Torkamanasadi, Yazdan Rezaei, Farid Najafi,
Volume 20, Issue 1 (6-2024)
Abstract
Background and Objectives: During the COVID-19 pandemic, vaccination was crucial in preventing the spread of SARS-CoV-2 and saving numerous lives. Countries implementing COVID-19 vaccination programs have reported significant reductions in cases, ICU admissions, and COVID-19-related deaths. This study aimed to evaluate the effectiveness of vaccines used in Hamadan province, explicitly focusing on their impact on hospitalization and death caused by COVID-19.
Methods: A test-negative case-control design (TND) was conducted involving patients aged 12 and above who were admitted to hospitals in Hamadan province, Iran, and had symptoms of acute respiratory diseases. Data were extracted from hospital and health system databases. Multiple logistic regression analysis was performed to estimate vaccine effectiveness for the first, second, and reminder doses in prevention of hospitalization, and severe outcomes (ICU admission or death).
Results: The study was conducted on 3,702 patients, and the maximum effectiveness of vaccines against hospitalization was 50% for patients who received a booster dose. The effectiveness of the first dose of vaccine on severe outcomes (admission to ICU or death) was estimated as 42%, but the effectiveness of the vaccines in the second and booster doses were not significant.
Conclusion: Despite the predominant use of inactivated virus vaccines and delayed initiation of vaccination in Iran, this study shows the effect of vaccination on reducing hospitalization and improving the outcomes of COVID-19. The use of more effective vaccines at a more appropriate time plays an important role in reducing the burden on health services and preventing further transmission in future epidemics.
