Tracking SARS-CoV-2 variants through pandemic waves using RT-PCR testing in low-resource settings

Authors

Asghar Nasir, Aga Khan UniversityFollow
Akber Kanji, Aga Khan UniversityFollow
Ali Raza Bukhari, Aga Khan University
Zeeshan Ansar Ahmed, Aga Khan UniversityFollow
Najia Bano Ghanchi, Aga Khan UniversityFollow
Kiran Iqbal Masood, Aga Khan UniversityFollow
Azra Samreen, Aga Khan UniversityFollow
Nazneen Islam, Aga Khan UniversityFollow
Samina Ghani, Aga Khan UniversityFollow
Syed Faisal Mahmood, Aga Khan UniversityFollow
Zahra Hasan, Aga Khan UniversityFollow

Document Type

Article

Department

Pathology and Laboratory Medicine

Abstract

COVID-19 resulted in extensive morbidity and mortality worldwide. SARS-CoV-2 evolved rapidly, with increasing transmission due to Variants of Concern (VOC). Identifying VOC became important but genome submissions from low-middle income countries (LMIC) remained low leading to gaps in genomic epidemiology. We demonstrate the use of a specific mutation RT-PCR based approach to identify VOC in SARS-CoV-2 positive samples through the pandemic in Pakistan. We selected 2150 SARS-CoV-2 PCR positive respiratory specimens tested between April 2021 and February 2022, at the Aga Khan University Hospital Clinical Laboratories, Karachi, Pakistan. Commercially available RT-PCR assays were used as required for mutations in Spike protein (N501Y, A570D, E484K, K417N, L452R, P681R and deletion69_70) to identify Alpha, Beta, Gamma, Delta, and Omicron variants respectively. Three pandemic waves associated with Alpha, Delta and Omicron occurred during the study period. Of the samples screened, VOC were identified in 81.7% of cases comprising mainly; Delta (37.2%), Alpha (29.8%) and Omicron (17.1%) variants. During 2021, Alpha variants were predominant in April and May; Beta and Gamma variants emerged in May and peaked in June; the Delta variant peaked in July and remained predominant until November. Omicron (BA.1) emerged in December 2021 and remained predominant until February 2022. The CT values of Alpha, Beta, Gamma and Delta were all significantly higher than that of Omicron variants (p<0.0001). We observed VOC through the pandemic waves using spike mutation specific RT-PCR assays. We show the spike mutation specific RT-PCR assay is a rapid, low-cost and adaptable for the identification of VOC as an adjunct approach to NGS to effectively inform the public health response. Further, by associating the VOC with CT values of its diagnostic PCR we gain information regarding the viral load of samples and therefore the level of transmission and disease severity in the population.

Comments

Pagination are not provided by the author/publisher.

Publication (Name of Journal)

PLOS Global Public Health

Recommended Citation

Nasir, A., Kanji, A., Bukhari, A. R., Ahmed, Z. A., Ghanchi, N., Masood, K. I., Samreen, A., Islam, N., Ghani, S., Mahmood, S. F., Hasan, Z. (2023). Tracking SARS-CoV-2 variants through pandemic waves using RT-PCR testing in low-resource settings. PLOS Global Public Health, 3(6), e0001896.
Available at: https://ecommons.aku.edu/pakistan_fhs_mc_pathol_microbiol/1456