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. 2021 Mar 18;11(1):6233.
doi: 10.1038/s41598-021-85428-7.

Characterizing the Qatar advanced-phase SARS-CoV-2 epidemic

Laith J Abu-Raddad  1   2   3 , Hiam Chemaitelly  4   5 , Houssein H Ayoub  6 , Zaina Al Kanaani  7 , Abdullatif Al Khal  7 , Einas Al Kuwari  7 , Adeel A Butt  7 , Peter Coyle  7 , Andrew Jeremijenko  7 , Anvar Hassan Kaleeckal  7 , Ali Nizar Latif  7 , Robert C Owen  7 , Hanan F Abdul Rahim  8 , Samya A Al Abdulla  9 , Mohamed G Al Kuwari  9 , Mujeeb C Kandy  9 , Hatoun Saeb  9 , Shazia Nadeem N Ahmed  10 , Hamad Eid Al Romaihi  10 , Devendra Bansal  10 , Louise Dalton  10 , Mohamed H Al-Thani  10 , Roberto Bertollini  10
Affiliations

Characterizing the Qatar advanced-phase SARS-CoV-2 epidemic

Laith J Abu-Raddad et al. Sci Rep. .

Abstract

The overarching objective of this study was to provide the descriptive epidemiology of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic in Qatar by addressing specific research questions through a series of national epidemiologic studies. Sources of data were the centralized and standardized national databases for SARS-CoV-2 infection. By July 10, 2020, 397,577 individuals had been tested for SARS-CoV-2 using polymerase-chain-reaction (PCR), of whom 110,986 were positive, a positivity cumulative rate of 27.9% (95% CI 27.8-28.1%). As of July 5, case severity rate, based on World Health Organization (WHO) severity classification, was 3.4% and case fatality rate was 1.4 per 1,000 persons. Age was by far the strongest predictor of severe, critical, or fatal infection. PCR positivity of nasopharyngeal/oropharyngeal swabs in a national community survey (May 6-7) including 1,307 participants was 14.9% (95% CI 11.5-19.0%); 58.5% of those testing positive were asymptomatic. Across 448 ad-hoc testing campaigns in workplaces and residential areas including 26,715 individuals, pooled mean PCR positivity was 15.6% (95% CI 13.7-17.7%). SARS-CoV-2 antibody prevalence was 24.0% (95% CI 23.3-24.6%) in 32,970 residual clinical blood specimens. Antibody prevalence was only 47.3% (95% CI 46.2-48.5%) in those who had at least one PCR positive result, but 91.3% (95% CI 89.5-92.9%) among those who were PCR positive > 3 weeks before serology testing. Qatar has experienced a large SARS-CoV-2 epidemic that is rapidly declining, apparently due to growing immunity levels in the population.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
Anti-SARS-CoV-2 prevalence assessed at different time intervals for the duration between the first PCR positive test and the antibody test. PCR polymerase chain reaction.
Figure 2
Figure 2
Association of age with (A) SARS-CoV-2 severe infection, (B) SARS-CoV-2 critical infection, and (C) COVID-19 death, adjusted for sex, nationality, and time of PCR testing. Severe infections, critical infections, and COVID-19 deaths were defined based on the World Health Organization criteria for classifying SARS-CoV-2 infection severity and COVID-19-related death.
Figure 3
Figure 3
Temporal trend in (A) crude case severity rate and (B) crude case fatality rate in Qatar.
See this image and copyright information in PMC

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