He gave the warning on Monday at the Presidential Task Force briefing.
The warning is coming a few hours after schools resumed in many states.
He noted that 10 per cent of COVID-19 cases in the country are under 19 years old.
Ehanire said, “With regard to COVID-19 and growing complacency, it is important to stress that, even though adults, especially those 60 years and above are more vulnerable, complications do occur in all age groups. Records show that 10% of all positive cases we have treated are below the age of 19 years.
“They are also the same mobile group that can be without symptoms, but can easily spread the disease. Therefore, as schools begin to reopen in some areas, I urge caution and adherence to the protocols and advisories for reopening schools, in order to join us to prevent the COVID-19 surge.
“As we reopen our economy, it is time for us to take preventive measures even more seriously.”
The Nigeria Centre for Disease Control on Sunday announced 97 new COVID-19 infections in the country, bringing the total confirmed cases to 57, 242 nationwide.