SARS-CoV-2 Seroepidemiological Investigation in Jordan: Seroprevalence, Herd Immunity, and Vaccination Coverage. A Population-Based National Study

Sami Sheikh Ali, Khalid A. Kheirallah, Ghazi Sharkas, Mohammed Al-Nusair, Abdel Hameed Al-Mistarehi, Mahmoud Ghazo, Ali Zeitawi, Saverio Bellizzi, Mohannad Ramadan, Jomana W. Alsulaiman, Hamed Alzoubi, Adel Belbesi, Mohammed Z. Allouh

Research output: Contribution to journalArticlepeer-review


Background: Population-based serosurveillance is a cornerstone to furthering our understanding of the COVID-19 pandemic at the community levels. In Jordan, four waves (phases) of seroprevalence epidemiological investigations were conducted using representative population-based national samples. This study aims to estimate the population-based seropositivity, herd immunity, and vaccination coverage at the fourth wave. Methods: Multistage sampling technique was implemented to recruit a nationally representative sample for the fourth wave of the seroprevalence investigation (June to August 2021). Electronically collected data utilized a questionnaire on background demo-graphics, chronic diseases, and COVID-19 vaccination history. Also, blood samples were collected to detect the presence of total Anti-SARS-CoV-2 IgM and IgG using Wantai/ELISA assays. Prevalence estimates were presented using percentage and 95% Confidence Intervals (C.I.). Results: There were 8821 participants included in this study, with a mean age of 31.3 years, and 61.7% were females. COVID-19 national seroprevalence and vaccination coverage estimates were 74.1% (95% C.I.: 73.1–74.9%) and 38.4% (95% C.I.: 37.1–39.6%), respectively. Among children, seroprevalence estimates were similar to unvaccinated adults. Among COVID-19 adults, 57.2% were vaccinated. Among vaccinated participants, 91.5% were seropositive, while among unvaccinated, 63.2% were seropositive. By age group, seroprevalence ranged between 53.0% and 86.9%. Seroprevalence estimates were significantly different by gender, vaccination status and dose, and residence. Conclusion: The reported interplay between seropositivity and vaccination coverage estimate seems insufficient to provide herd immunity levels to combat new variants of SARS-CoV-2. Children and healthcare workers seem to be an epidemiologically influential group in spreading COVID-19. As the globe is still grappling with SARS-CoV-2 infection, national seroepidemiological evidence from Jordan calls for more focus on vaccination coverage, especially among epidemiologically vulnerable groups, to optimize herd immunity.

Original languageEnglish
Pages (from-to)7053-7062
Number of pages10
JournalInternational Journal of General Medicine
Publication statusPublished - 2022


  • COVID-19
  • Jordan
  • Middle East
  • SARS-CoV-2
  • herd immunity
  • seropositivity
  • seroprevalence
  • vaccination

ASJC Scopus subject areas

  • General Medicine


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