Parents should not linger at the school gates while dropping off their children, the Scottish government said.
Pupils in years one to three are due back at school in Scotland from Monday, along with some senior students undertaking vocational courses.
The number of people dying from Covid-19 continues to decline, but Scottish Education Secretary John Swinney said there was little “headroom” in the infection rate so parents should not let their guard down at the school gate.
“I know this can be quite controversial at times but adults making sure they follow all of the physical distancing requirements at the school gate, or the mask-wearing requirements, is critical to make sure that the return of young children – who are much less susceptible to transmitting the virus – is not in some way undermined by the fact that there is essentially parental transmission,” he told the BBC.
“We’ve all got to play a part, not just the school environment but the whole surrounding environment of society, to make sure that we do all that we can to suppress the virus.”
Other pupils are unlikely to return to Scottish schools before March 15 at the earliest under the staggered reopening plan, as the authorities continue to monitor infection rates.
“We don’t actually have an awful lot of headroom between where the R level is just now – somewhere between 0.7 and 0.9 – and 1, where the virus begins to spread exponentially,” Mr Swinney said.
In Wales, pupils aged three to seven will also return on Monday while in England, all schoolchildren are expected to return on March 8.
Paul Whiteman from the National Association of Head Teachers said it was still too risky for all schools to return at the same time.
“We’re worried about the effects of a big bang approach,” he said. “Let’s get children back, it’s the right thing to do, but let’s do it on a basis that we can maintain.
“We’re hoping that the government can make its policy decision credible with a good explanation as to what data it relies on and why the government thinks it wouldn’t result in a spike that leads to another lockdown.
“To have a third lockdown of schools would be more devastating than taking a longer run to get everybody back.”
UK Vaccines Minister Nadhim Zahawi said he was confident about the government’s cautious approach.
"It’s no coincidence that March 8 has been chosen because the middle of February is when we've offered the vaccine to the top four cohorts - three weeks after the first dose is when protection kicks in," he said.
"We are being deliberately careful in allowing teachers the notice to be able to prepare."