There are now four schools in Lincolnshire to have reported a confirmed coronavirus case since June 1.
Isaac Newton Primary School in Grantham became the fourth Lincolnshire school to report a positive COVID-19 case.
Andy Fox, consultant in public health for Lincolnshire County Council, said: “We would like to reassure people that these all appear to be isolated cases, and there are no indications of an ‘outbreak’ at any local school.
“Each school has taken the appropriate action to limit the potential spread of the virus, and parents have been informed.
“The schools are all open with those affected self-isolating in line with guidance.”
Isaac Newton school will remain open for the rest of the pupils and staff, with just the social bubble of the child who tested positive being closed.
Peter Bell, CEO of Community Inclusive Trust Academies, said: “A diagnosis was confirmed on Friday, June 12, and in line with DfE guidance, the bubble will remain closed for 14 days from onset of symptoms. I wish the family well and a speedy recovery.”