COVID-19 Delta variant found to be predominant despite Covishield, Covaxin doses: AIIMS study
A preliminary study conducted by the All India Institute of Medical Science (AIIMS) Delhi claimed that the presence of Covid-19 Delta variant (B1.617.2) is predominantly found even after getting a single dose or both doses of Covid-19 vaccine.
New Delhi: There’s still so much around novel coronavirus that researchers and scientists are exploring on a regular basis.
The 'delta' variant of Covid-19 - the version first detected in India in October last year - is capable of infecting people even after they have received both doses of the Covaxin or Covishield vaccines, according to separate studies by AIIMS (Delhi) and the National Centre for Disease Control (NCDC).
The study included 63 people who got breakthrough infections; of which 36 patients received two doses, while 27 had received one dose of vaccine.
"SARS-CoV-2 lineages could be assigned for a total of 36 (57.1%) samples, 19 (52.8%) in patients who completed both doses and 17 (47.2%) in patients who completed only a single dose. B.1.617.2 was found to be the predominant lineage with 23 samples (63.9%) out of which 12 were in fully vaccinated and 11 in partially vaccinated groups. 4 (11.1%) and 1 (2.8%) samples were assigned the lineages B.1.617.1 and B.1.1.7 respectively. The B.1.617.2 lineage was first described in India and associated with increased transmissibility as well as immune escape and has grown to become one of the predominant lineages in India," the AIIMS study said.
76.9 % of infections by the 'delta' variant were recorded in people who had received a single dose, and 60 % in people who had received both doses.
Data from the NCDC-IGIB study indicated that breakthrough infections due to the 'delta' variant seemed to affect people who took Covishield.
Importantly, data from both studies indicated the ‘alpha’ variant is also proving resistant to Covishield and Covaxin, but not as significantly as the version first reported from India. Both studies also indicated that while the vaccine’s protection against the ‘delta’, and even ‘alpha’, variants may be reduced, severity of infection in each case appeared to be unaffected as a result.
This is in line with scientists’ views that there is, as yet, no evidence the ‘delta’ variant is causing a greater number of Covid-linked deaths or more severe infections.
The patients included health care workers (24, 13 of which were from the same hospital) and close analysis of the genomic sequences suggests that the samples clustered separately with origins closely clustering with lineages from different states, suggesting the disease transmission happened most likely from different and independent sources.
The study also made the comment on the prevalence of Delta variant in Delhi and said, "Reinfections and vaccine breakthrough infections are rare occurrences and genomic sequencing of vaccine breakthrough infections can provide useful insights. In the present group of vaccine breakthrough infections investigated using genome sequencing, closely overlapping and mirroring the Covid-19 cases in the state of Delhi, the variants of concern B.1.617.2 and B.1.1.7 comprised the majority, but the proportions were not significantly different in comparison with the population prevalence of the variants during this period with high community transmission."
However, please note that neither study has been peer-reviewed as yet, as per the reports.
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