Introduction: This study assessed the incidence and severity of side effects associated with coronavirus disease 2019 (COVID-19) vaccination among healthcare workers registered with the Medical Council of the Islamic Republic of Iran. Methodology: A retrospective cohort study was conducted on the healthcare workers focusing on the side-effects of COVID-19 vaccines from March to June 2021. Data were collected using online questionnaires. Multivariable logistic regression was used to assess the association between side effects of the vaccines and demographic variables, comorbidities, vaccine type, and history of COVID-19. Results: Out of 42,018 people who were included, 55.85% reported at least one side effect after receiving the first vaccine dose. 4.59% of those with side effects sought diagnostic intervention or were referred to treatment centers. Multivariable logistic regression indicated that being a woman, higher education, having a history of COVID-19 infection, and having comorbidities increased the risk of side effects. The AstraZeneca vaccine significantly increased the risk of side effects compared to the Sputnik vaccine, while the Sinopharm vaccine decreased this risk. The risk of developing a side effect decreased with age. The risk of moderate and severe side effects was significantly associated with gender, younger age, comorbidities, and a history of COVID-19 infection. Moderate and severe side effects were less reported by those who received the Sinopharm vaccine. Conclusions: Clinical complications after COVID-19 vaccination, directly or indirectly caused by the vaccines, are common. However, the benefits of COVID-19 vaccines greatly outweigh the risk of reversible side effects, especially among the high-risk population.

Reinfection with SARS-Cov-2 after recovery can occur that most of them don’t require hospitalization. The aim of this study is estimation of out-patient COVID-19 reinfection and recurrence rates and its associated factors among Iranian patients with history of confirmed SARS-Cov-2 infection and hospitalization. This study is a retrospective cohort conducted from May 2021 to May 2022 in Iran. The national Medical Care Monitoring Center (MCMC) database, obtained from the Ministry of Health and Medical Education, includes all information about confirmed COVID-19 patients who are hospitalized and diagnosed during the pandemic. Using probability proportional to size sampling from 31 provinces, 1,532 patients over one years of age with a history of hospitalization in the MCMC data are randomly selected. After that, interviews by phone are performed with all of the selected patients using a researcher-made questionnaire about the occurrence of overall reinfection without considering the time of infection occurrence, reinfection occurring at least 90 days after the discharge and recurrence (occurring within 90 days after discharge). Univariate and multivariable Cox regression analyses are performed to assess the factors associated with each index. All of the analyses are performed using Stata software version 16. In general, 1,532 phone calls are made, out of which 1,095 individuals are willing to participate in the study (response rate ≃ 71

Introduction: Reinfection and hospital readmission due to COVID-19 were significant and costly during the pandemic. This study aimed to assess the rate and risk factors of SARS-Cov-2 reinfection, recurrence, and hospital readmission, by analyzing the national data registry in Iran. Methods: This study was a retrospective cohort conducted from March 2020 to May 2021. A census method was used to consider all of the possible information in the national Medical Care Monitoring Center (MCMC) database obtained from the Ministry of Health and Medical Education; the data included information from all confirmed COVID-19 patients who were hospitalized and diagnosed using at least one positive Polymerase Chain Reaction (PCR) test by nasopharyngeal swab specimens. Univariate and multivariable Cox regression analyses were performed to assess the factors related to each studied outcome. Results: After analyzing data from 1,445,441 patients who had been hospitalized due to COVID-19 in Iran, the rates of overall reinfection, reinfection occurring at least 90 days after the initial infection, recurrence, and hospital readmission among hospitalized patients were 67.79, 26.8, 41.61, and 30.53 per 1000 person-years, respectively. Among all cases of hospitalized reinfection (48292 cases), 38.61% occurred more than 90 days from the initial SARS-Cov-2 infection. Getting infected with COVID-19 in the fifth wave of the disease compared to getting infected in the first wave (P<0.001), having cancer (P<0.001), chronic kidney disease (P<0.001), and age over 80 years (P<0.001) were respectively the most important risk factors for overall reinfection. In contrast, age 19-44 years (P<0.001), intubation (P<0.001), fever (P<0.001), and cough (P<0.001) in the initial admission were the most important protective factors of overall reinfection, respectively. Conclusion: Reinfection and recurrence of COVID-19 after recovery and the rate of hospital readmission after discharge were remarkable. Advanced or young age, as well as having underlying conditions like cancer and chronic kidney disease, increase the risk of infection and readmission.

Background Pregnant women infected with the coronavirus disease 2019 (COVID-19) are at risk for adverse pregnancy outcomes, and the only real preventive strategy against COVID-19 is mass vaccination. This study aimed to examine the effectiveness, immunogenicity, and safety of Covid-19 vaccination in pregnant women. Methods A combination of search terms was performed by 2 researchers independently in the Web of Science, PubMed, and Scopus databases, the World Health Organization website, and the US Centers for Disease Control (CDC) website up to February 2022. After the selection of eligible studies, the review process, description, and summarization of the selected studies were performed by the research team. Results Finally, 22 articles were included in this study. Evidence supports the safety of COVID-19 vaccination during pregnancy. There is no risk of transmitting COVID-19 to infants during lactation. In addition, antibodies made by vaccination can protect infants through breast milk. Conclusion The scientific community believes that being vaccinated as soon as possible is the best course of action because there is no evidence to suggest that the COVID-19 vaccine poses a risk to expectant or nursing women.

Objectives This study aimed to determine factors associated with intensive care unit (ICU) admission in patients hospitalised due to COVID-19. Design Retrospective cohort. Setting Confirmed hospitalised patients from all over Iran were considered for the study. Participants All patients with COVID-19 admitted to the hospital from March 2020 to May 2021 were included by census. ICU admission was defined by the following criteria: (1) admission to the ICU ward; (2) level of consciousness (loss of consciousness); and (3) use of invasive ventilation. Methods This is a secondary data analysis from the Medical Care Monitoring Center. The association between different variables and ICU admission was assessed by forward Logistic regression and restricted cubic spline method. Results The mean age of the 1 469 620 patients with COVID-19 was 54.49±20.58 years old, and 51.32% of the patients were male. The prevalence of ICU admission was 19.19%. The mean age of patients admitted to the ICU was higher than that of other hospitalised patients (62.49±19.73 vs 52.59±20.31 years). The prevalence of ICU admission was 17.17% in the first, 21.52% in the second, 19.72% in the third, 21.43 in the fourth and 17.4% in the fifth wave. In the multivariable model, age groups, sex, waves of the epidemic, comorbidities and saturation of peripheral oxygen (SpO 2 ) <93% and acute respiratory distress syndrome (ARDS) were associated with an increased odds of ICU admission. The OR for ICU admission indicates a significant protective effect at a young age and then a significant risk factor for admission to the ICU ward at an old age. Conclusions Men, older adults, people who suffer from ARDS, patients with SpO 2 levels of less than 93% and cases with comorbidities had the highest odds of ICU admission. Therefore, these groups should take all necessary precautions to avoid contracting COVID-19.

Objectives: This study aims to investigate the risk factors associated with severity and death from COVID-19 through a systematic review and meta-analysis of the published documents in Iran. Methods: A systematic search was performed based on all articles indexed in Scopus, Embase, Web of Science (WOS), PubMed, and Google Scholar in English and Scientific Information Database (SID) and Iranian Research Institute for Information Science and Technology (IRA)NDOC indexes in Persian. To assess quality, we used the Newcastle Ottawa Scale. Publication bias was assessed using Egger's tests. Forest plots were used for a graphical description of the results. We used HRs, and ORs reported for the association between risk factors and COVID-19 severity and death. Results: Sixty-nine studies were included in the meta-analysis, of which 62 and 13 had assessed risk factors for death and severity, respectively. The results showed a significant association between death from COVID-19 and age, male gender, diabetes, hypertension, cardiovascular disease (CVD), cerebrovascular disease, chronic kidney disease (CKD), Headache, and Dyspnea. We observed a significant association between increased white blood cell (WBC), decreased Lymphocyte, increased blood urea nitrogen (BUN), increased creatinine, vitamin D deficiency, and death from COVID-19. There was only a significant relationship between CVD and disease severity. Conclusion: It is recommended that the predictive risk factors of COVID-19 severity and death mentioned in this study to be used for therapeutic and health interventions, to update clinical guidelines and determine patients' prognoses.