Chennai: At least 68% of the children aged between 11 and 18 years who were unvaccinated had immunity against SARS-CoV-2, the virus that causes Covid-19, according to the results of the phase -IV serosurvey conducted by the Directorate of Public Health in the last week of December 2021.
The fourth edition of the survey released on Wednesday showed 87% of people had immunity — natural or vaccine induced — against the virus.