Seroprevalence of SARS-CoV-2(Covid-19) antibody among blood donors in a
tertiary care centre in South India
Abstract
INTRODUCTION The novel severe acute respiratory syndrome virus
2 (SARS-CoV-2), which is responsible Coronavirus disease (COVID-19),
spread worldwide from China, causing a pandemic from late December 2019.
Due to the high proportion of asymptomatic or mild infections
(approximately 80%), data restricted to laboratory-confirmed cases do
not capture the true extent of the spread or burden of the virus, or its
infection-fatality ratio. Therefore, serological detection of specific
antibodies against SARS-CoV-2 can better estimate the true number of
infections. The current study aims to estimate the seroprevalence of
SARS-CoV-2 antibodies among the whole blood donors without any prior
COVID-19 history or symptoms. OBJECTIVE 1. To determine
seroprevalence of SARS-CoV-2 (COVID-19) antibody (IgG and IgM) among
asymptomatic healthy blood donors. METHODS This was a cross
sectional study conducted between March and July, 2021 among 300 blood
donors without any prior COVID-19 history or symptoms who came to a
tertiary care, multispecialty hospital in south India. Any donor who had
recently travelled abroad or donors who had received COVID-19 vaccine
are excluded from the study. 3 ml venous blood was drawn in EDTA tube
from participants and was tested by “Access SARS CoV-2 IgG assay” and
“Access SARS CoV-2 IgM assay” by UniCel DxI 800 Immunoassay analyzer
(Beckman coulter). The Access SARS CoV-2 IgG assay and the Access SARS
Cov-2 IgM assay detect antibodies to the Receptor Binding Domain (RBD)
of the Spike Protein. Result was reported as Reactive if Signal/Cut-off
(S/CO)>1.0 and non-Reactive if S/CO <1. Data was
collected and entered into excel sheets and was analyzed by using the
software SPSS version 25. RESULTS A total of 300 healthy blood
donors were included. The study reported seroprevalence of 15.3% for
IgG and 4.3% for IgM (95%CI) among asymptomatic whole blood donors. No
significant difference was observed across age groups, diet, BMI, ABO/Rh
blood type or Ayurveda/homeo immune medicine intake with respect to IgG
and IgM reactivity. CONCLUSION 15% of blood donors were
seroconverted for COVID-19 during second wave. This is a reflection of
widespread seroprevalence in the adult population. Real-time
seroprevalence studies will help to know the herd immunity among the
blood donors which will assist in knowing the COVID-19 transmission
dynamics and distribution of immunity levels at a particular point in
time. KEYWORDS COVID-19, Seroprevalence, Blood donors.