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. 2021 Apr 12;43(1):3-8.
doi: 10.1093/pubmed/fdaa170.

Seroprevalence of anti-SARS-CoV-2 antibodies in residents of Karachi-challenges in acquiring herd immunity for COVID 19

Samreen Zaidi  1 , Faiza Rizwan  2 , Quratulain Riaz  3 , Asma Siddiqui  4 , Shabnam Khawaja  5 , Mehjabeen Imam  6 , Arshi Naz  3 , Samra Waheed  3 , Tahir Shamsi  3
Affiliations

Seroprevalence of anti-SARS-CoV-2 antibodies in residents of Karachi-challenges in acquiring herd immunity for COVID 19

Samreen Zaidi et al. J Public Health (Oxf). .

Abstract

Background: The recent pandemic by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a global emergency. There is large number of asymptomatic cases of SARS-CoV-2 that are not reported. Hence, serological evidence of SARS-CoV2 antibodies is warranted for a better estimation of the actual number of infected patients to limit the disease spread and to get an idea of herd immunity.

Methods: This is a cross-sectional study conducted from May 2020 to July 2020 at National Institute of Blood Diseases at Pakistan. The study includes healthcare workers (HCWs), community and industrial workers. The anti-SARS-CoV-2 test was performed by electrochemiluminescence immunoassay analyzer.

Results: A total of 1675 samples have been received from three groups of population. The percentage positivity for industrial employees is high (50.3%) for HCW (13.2%) and community population (34%).Total percentage for positive antibodies result is ~36%.

Conclusion: Our seroprevalence is 36%, which still far from herd immunity that needs to be at least 60-70% in population. If we consider acquiring 60% seroprevalence in next few months, then herd immunity is not far from reality, provided the antibodies did not decline with time. Although the current study is based on a small sample of participants, the findings suggest a study with larger population to implement stronger and targeted interventions.

Keywords: infectious disease; public health.

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Figures

Fig. 1
Fig. 1
The figure showing the percentage inclusion of various residents including HCW, industrial employees and community population.
Fig. 2
Fig. 2
The above graph shows the percentage positivity for SARS-CoV-2 antibodies for HCW, industrial employees and community.
See this image and copyright information in PMC

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