Until a sizeable number of the population are vaccinated, Covid-appropriate behaviour needs to be followed aggressively, he said and stressed on the need for stricter surveillance and area-specific lockdowns in case of a significant surge.
Guleria reiterated that till now, there is no evidence to suggest that children will be affected more in the next wave of the infection.
Earlier, India's epidemiologists had indicated that a third wave of COVID-19 is inevitable and is likely to start from September-October.
India was hit severely by a brutal second wave of the COVID-19 pandemic in April and May, claiming a massive number of lives daily, with shortage in oxygen supply at various hospitals adding to the woes.
However, the number of cases have shown a downward trend and the positivity rate too has been shrinking in the last several days. From a daily case count of over 4 lakh, the number of new COVID-19 cases has been hovering around 60,000 in the last couple of days.
''If Covid-appropriate behaviour is not followed, the third wave can happen in six to eight weeks. We need to work aggressively to prevent another large wave till vaccination kicks in,'' Guleria told PTI.
There needs to be aggressive surveillance strategy in Covid hotspots and lockdowns in case of any significant surge. The moment a significant surge in cases in noted in a particular area and the positivity rate goes beyond 5 per cent, area-specific lockdown and containment measures should be implemented, he said.
''However, a national-level lockdown cannot be a solution (to rein in the pandemic) keeping economic activity in mind.'' With 60,753 new Covid cases being reported in a day, India's total tally rose to 2,98,23,546, while the number of active cases stand at 7,60,019, the lowest in 74 days, according to Union health ministry data updated on Saturday.
The death toll climbed to 3,85,137 with 1,647 fresh fatalities and active cases comprise 2.55 per cent of the total infections, while the national COVID-19 recovery rate has improved to 96.16 per cent, the data updated at 8 am showed.