New Delhi: Delta was the predominant variant that affected Indian children during the second wave of the Covid pandemic in 2021, a study by the Indian Council of Medical Research (ICMR) has shown.
The study, a preprint uploaded on medRxiv, analysed paediatric samples collected between March and June 2021 and highlighted the importance of genomic surveillance among paediatric Covid patients too.
“Out of 512 sequences, 372 were VOCs (variants of concern), 51 were VOIs (variants of interest). Most common lineages observed were Delta, followed by Kappa, Alpha and B.1.36, seen in 65.82 per cent, 9.96 per cent, 6.83 per cent and 4.68 per cent, respectively in the study population,” the researchers wrote.
A ‘variant of interest’ differs from a ‘variant of concern’ on account of the evidence available about its potential to cause more severe disease or effect changes in other virus characteristics.
“Overall, it was observed that Delta strain was the leading cause of SARS-CoV-2 infection in Indian children during the second wave of the pandemic. We emphasise on the need of continuous genomic surveillance in SARS-CoV-2 infection even amongst children.”
The 1,751 Indian paediatric SARS-CoV-2 sequences available with the GISAID database — collection date from January 2020 to 31 July 2021 — were also analysed.
Set up in 2008, GISAID is an international initiative aimed at sharing scientific data pertaining to influenza and coronaviruses.
The researchers said Delta continues to be the predominant Covid strain in children. India’s fourth serosurvey that was carried out during the first half of 2021 showed that about 50 per cent of the surveyed children had antibodies against the SARS-CoV-2 virus.
Delta is believed to have largely driven the surge during March-May 2021 that caused major casualties and widespread infection in India. However, there is limited information on the nature of the strains infecting children during this period, the researchers pointed out.
The Delta predominance built over time. Between January to March 2021, a higher number of cases of the Alpha variant was reported, but the higher infectivity of Delta ensured that it rapidly became the predominant strain. The researchers found that the B.1.617.2 (Delta) variant showed a steep rise after March 2021, reaching 100 per cent among the samples collected in June.
“The second wave of the Covid-19 in the world witnessed the emergence of variants of concern (Alpha, Beta, Gamma, Delta) and VOIs [Kappa, Zeta, Lambda (C.37)] in adults. In India, the first paediatric case infected with Alpha strain was reported in November 2020. Further, an increase in the number of cases was observed with Alpha and the Delta variants,” the researchers wrote.
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State-wise variations
While the broad national trends showed a preponderance of the Delta variant over time, there were significant sub-national variations in the data. The Delta lineage predominated in Karnataka, Uttar Pradesh, Madhya Pradesh and Telangana, whereas the Kappa variant was observed in Maharashtra, Rajasthan and Chandigarh.
Both Kappa (B.1.617.1) and Delta are variants that are believed to have originated in India and were later named after Greek alphabets in keeping with World Health Organization (WHO) norms.
The distribution of SARS-CoV-2 variants among minors seems to mirror their prevalence in adults, the study found.
“The second wave of the Covid-19 in the world witnessed the emergence of variants of concern (Alpha, Beta, Gamma, Delta) and VOIs (Kappa, Zeta, Lambda (C.37)] in adults.…This study identifies the SARS-CoV-2 variant responsible for the infection in the paediatric population and highlights the importance of genomic surveillance in children,” the researchers concluded.
(Edited by Saikat Niyogi)
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