2nd Covid wave: Scientists report more infections in kids By IANS | 3 Views Kids produce different antibodies in response to Covid-19: Study. Image Source: IANS News Berlin, April 9 : Preschool and school children in Germany have been infected with SARS-CoV-2, the virus that causes Covid-19, three to four times more than reported via PCR testing during the second wave, a study has revealed. Preschool children showed an antibody frequency of 5.6 per cent from October 2020 to February 2021. Among school children who were tested between November 2020 and February 2021, the figure was as high as 8.4 per cent. Overall, the antibody frequency at the end of the second wave (January and February 2021) was about eight times higher compared to the end of the first wave (April to July 2020), revealed the study published in the journal Med.