Deputy Chief Medical Officer Dr Ronan Glynn has asked parents and children not to congregate outside schools or to organise after-school activities once schools return next week.
In a letter written to parents and guardians ahead of the resumption of primary and post-primary education, Dr Glynn said the National Public Health Emergency (Nphet) was concerned that household mixing and mobility associated with school might also recommence.
"We cannot afford for this to happen at this time," he said.
"I know these are difficult requests. We all – adults and children alike – want to meet up with our friends and neighbours and get back to our old routines. And we will get there."
Dr Glynn said it was only through adherence to these measures that children could "get back to school and then stay back in school.
The Deputy CMO said progress in reducing community transmission of the virus had allowed the phased reopening of childcare and education to take place.
He said the decision to reopen schools had been "carefully weighed" against the very real harm that could be caused by sustained school closures.
"Our priority is to ensure a safe return to schools for students, their families and school staff, which is why we have recommended a phased return to in-school learning," he said.
"Schools are at the heart of our communities and they play a fundamental role in the social lives and wellbeing of our children – this is particularly true for children who have special educational needs, are disadvantaged or who may have been disproportionately impacted by school closures over the last year."
However, Dr Glynn cautioned that despite recent progress, Covid-19 was still circulating at high levels in communities across the country.
"We must do all we can individually and collectively to ensure the reopening of schools results in the minimum possible upward pressure on the reproduction number," he said.
Echoing remarks made by the Taoiseach earlier this week, Dr Glynn said ongoing Covid-19 vaccinations administered to healthcare workers, older people, and those most at risk was having a significant positive impact on society.
Dr Glynn said the vaccine roll-out, together with continued suppression of the disease through March and April, would give the country "many more options" in terms of easing of restrictions.
In closing, Dr Glynn thanked parents and guardians for all they had done to keep families and communities safe over the last year.
He also thanked teachers, principals and school staff for the work they had done "to ensure measures have been put in place to limit the risk of spread of Covid-19 in schools".
"It has been this kind of work, done quietly and by the majority, which has underpinned our national response and which, ultimately, will see us through to brighter days ahead."