There have been calls to extend the school year to try and make up for time that was lost during the strict lockdown, an expert group has said.
Schools across Cork and around the country have been reopening this week and will continue over the coming weeks after shutting their doors in mid-March.
More than 567,000 primary schoolchildren were affected by the closures.
A national clinical review on the impact of Covid-19 restrictions on children found that children's educational progress has been halted because of the widespread closures.
The report, complied by the HSE and the Royal College of Physicians, outlined the impact of school closures on students and their families.
It found that primary schoolchildren are most affected because they are unable to participate in self-directed learning and are in need of constant support and direction.
It stated that recently acquired knowledge is vulnerable to loss and the critical period for attainment of literacy skills and specifically reading is up to eight years.
"Reading ability is the foundation for on-going vocabulary development and for wider educational attainment," the report added.
"Delays in this development will have knock on effects.
"Interaction with their peers, teaching staff and the wider school community is important for the development of children's communication, physical and social skills."
The authors of the report included Dr Ellen Crushell, national clinical lead for children, Dr John Murphy, national neonatology clinical lead and Jacqueline de Lacy, programme manager for NCP Children.
They stated: "It is our collective opinion that the two key adverse consequences for all children across the State are the prolonged closure of the schools and the curtailment of services to children - specifically paediatric medical services, GP services, and multidisciplinary community support services.
"We feel that there needs to be a recalibration of how children are catered for in this pandemic."
They also said that consideration should be given to extending the school year to "make up for lost time".
Among other findings, the experts said that children with additional learning and special needs are disproportionately affected by the school closures.
They need the structure of on-going access to their individualised learning plans supported by the special needs assistants (SNA), teachers and special education needs team within their school, the report added.
It found that the effects on children with complex disabilities and their families have been "profound" with many experiencing regression of skills that were not easily gained.
It is feared that anxiety levels for children may increase due to lack of socialisation and loss of routines.
"The State uses schools as a mechanism for the implementation of support services such as school meals, child protection issues, vaccination, dental and hearing and screening programmes - these are significant public health issues that need to supported and protected through the school system," the report added.
"There are added concerns about child welfare due to rise in family distress, domestic violence, parental alcohol intake and excessive time being spent by children on the internet.
"Educational settings are a natural area of vigilance of child welfare."