A longitudinal five-month study jointly conducted by Max Super Specialty Hospital, Saket, and the CSIR-Institute for Genomics and Integrative Biology has suggested that antibodies against Covid-19 can stay longer than 60 days, providing immunity against the virus.
The findings of the study, titled ‘SARS-CoV-2 antibody seroprevalence and stability in a tertiary care hospital-setting’, available as a preprint in the MedRxiv journal, are in contrast to a recently published study that showed such antibodies lasting less than 50 days.
For the study, the hospital tested and followed up with 780 people — 448 healthcare workers and 332 individuals who visited the hospital for Covid testing from April to August.
Dr Sujeet Jha, principal director, Endocrinology, Diabetes & Metabolism, at the hospital, said, “This is the first such preliminary report from India which provides evidence that the antibodies against SARS-CoV-2, once developed, could persist in the body for more than 60 days. The follow-up of seropositive individuals is still ongoing and further results would provide a clearer understanding of immune response against Covid-19 infection. This would be useful for vaccine development.”
According to the study, half of the patients tested at the hospital were found to be carrying antibodies against the virus. The researchers found 16.5% cumulative seroprevalence among healthcare workers and 23.5% among the individuals visiting the general flu-clinic.
“Nineteen individuals who were followed up for at least 40 days had persistent antibodies while 12 individuals sustained antibodies for 50 follow-up days, the study found. There were four individuals who were successfully followed for more than 60 days and showed sustenance of antibodies,” said Salwa Naushin, a PhD scholar at CSIR-Institute for Genomics and Integrative Biology.
The study showed that 67% of seropositive cases were asymptomatic, suggesting that antibodies can appear in individuals without them having any idea of even being exposed to the virus. Seroprevalence among hospital workers increased from 2.3% in April to 50.6% in July.
“This hints at the importance of asymptomatic carriers in estimating the disease burden in a population…this study was conceptualised with an aim to estimate seroprevalence in a hospital and general population and determine the stability of antibodies in healthcare workers,” said
Dr Shantanu Sengupta, senior principal scientist, CSIR-Institute for Genomics and Integrative Biology.
Meanwhile, Delhi reported 46 deaths due to Covid-19 on Saturday — the highest in 80 days — taking the death toll to 5,193. Daily positivity rate fell a little to 5.85% while the death rate, based on the last 10 days, was recorded at 0.94%.
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