• Frequency of occurrence, risk factors, and clinical characteristics of COVID-19 infection in northeastern of Iran
  • Raheleh Miri,1,* Arman Mosavat,2 Sanaz Ahmadi Ghezeldasht,3 Mohammadreza Hedayati moghaddam,4
    1. Blood Borne Infections Research Center, Academic Center for Education, Culture, and Research (ACECR), Razavi Khorasan, Mashhad, Iran
    2. Blood Borne Infections Research Center, Academic Center for Education, Culture, and Research (ACECR), Razavi Khorasan, Mashhad, Iran
    3. Blood Borne Infections Research Center, Academic Center for Education, Culture, and Research (ACECR), Razavi Khorasan, Mashhad, Iran
    4. Blood Borne Infections Research Center, Academic Center for Education, Culture, and Research (ACECR), Razavi Khorasan, Mashhad, Iran


  • Introduction: Since the first report of COVID-19 infection caused by SARS-CoV-2 in late 2019 in China, more than 7.6 million confirmed cases of this disease with over 146 thousand deaths have been reported in Iran. Common symptoms of the disease included fever, cough, muscle pain, and fatigue; some patients experienced gastrointestinal symptoms, while others reported loss of taste or smell. However, it seemed that these symptoms could vary over time depending on the virus strain, underlying diseases, and vaccination status. This cross-sectional study was conducted in Mashhad with the aim of determining the prevalence and risk factors of COVID-19 and the clinical symptoms of affected patients.
  • Methods: From September 2020 to March 2022, using a systematic random sampling method, a random sample of individuals visiting the COVID center laboratory at the academic center for education, culture and research was selected, and the confirmed prevalence of COVID-19 infection based on the PCR test results of nasal and throat swab samples was determined. The sample included 7,051 individuals, with 6 to 10 percent of visitors in each of the third to sixth waves of the disease. Additionally, data on demographic characteristics, disease symptoms, and underlying conditions were extracted from completed forms at the time of referral to the COVID center and compared for frequency between the two groups with and without COVID-19.
  • Results: In this study, data related to 4,411 men (62.6%) and 2,640 women (37.4%) with a mean age of 14.2 ± 37.8 years were analyzed, and SARS-CoV-2 infection was confirmed among 3,142 cases (44.6%). The prevalence of infection in the third, fourth, fifth, and sixth waves of COVID-19 was 45.5%, 47.7%, 48.9%, and 30.4%, respectively (P<0.001). Furthermore, the prevalence of infection was slightly higher in men compared to women, with rates of 46.4% and 41.5%, respectively (P<0.001). Out of 6,281 respondents, 3,856 individuals (61.4%) reported a history of at least one of the symptoms such as fever, chills, sore throat, cough, shortness of breath, and loss of smell or taste. The highest and lowest prevalence of symptomatic cases were observed in the third wave (67.4%) and the sixth wave (40.8%), respectively. The prevalence of confirmed COVID-19 among symptomatic individuals was significantly higher than among those without clinical symptoms, with rates of 55.5% and 28.2%, respectively (P<0.001). Additionally, the prevalence of the disease was significantly associated with a history of respiratory and renal disorders (P=0.003, P=0.029).
  • Conclusion: In this study, three-fifths of the participants reported a history of at least one case of COVID-19, yet only 44.6% of them had confirmed infection. The infection rate varied between 45% to 49% in the third, fourth, and fifth waves but decreased to 30% in the sixth wave
  • Keywords: Covid-19 Mashhad Frequency