LONDON: 50-70 per cent of “children” below the age of 19 were susceptible to the SARS-CoV-2 infection by the end of 2021 and before the commencement of the Omicron wave. This showcased a need for more effective vaccines and better vaccination coverage, according to a study.
It was also found that worldwide seroprevalence estimates varied from 7.3 per cent in the first wave of the Covid-19 pandemic to 37.6 per cent in the fifth wave and 56.6 per cent in the sixth wave.
Seroprevalence is defined as the percentage of people in a population who have proteins called antibodies in their blood that show they have been exposed to a virus or other infectious agent. The highest seroprevalences in different pandemic waves were estimated for South-East Asia—17.9 to 81.8 per cent—and the African region—17.2 to 66.1 per cent—while the lowest seroprevalence was estimated for the Western Pacific region between 0.01 and 1.01 per cent, the study said.
The study published in eClinicalMedicine stated seroprevalence estimates were higher in those children who were living in underprivileged countries and those who belonged to a minority ethnic background.
Seroprevalence was defined as the number of children who tested positive for specific anti-SARS-CoV-2 serum antibodies, using a well-designated threshold in the assay, divided by the total number of children tested. Scientists conducted a systematic review and meta-analysis in which they searched international and pre-printed scientific databases from December 1, 2019, to July 10, 2022, in order to assess SARS-CoV-2 seroprevalence and determinants in children worldwide.
Since the emergence of the Omicron variant, researchers observed that those aged 0-19 years and referred to as “children” by the study had higher rates of hospitalisation. This highlighted a need for in-depth knowledge of SARS-CoV-2 seroepidemiology in children. Pooled seroprevalences were estimated according to World Health Organization (WHO) regions using random-effects meta-analyses.
“Findings indicate that, by the end of 2021 and before the Omicron wave, around 50-70 per cent of children globally were still susceptible to SARS-CoV-2 infection, clearly emphasising the need for more effective vaccines and better vaccination coverage among children and adolescents...,” it said.