Prime Minister Narendra Modi said on Thursday that the strategy to deal with Covid-19 should be dynamic, innovative and constantly upgraded as he underlined the dangers posed by the virus which, he noted, is invisible and often mutates.

Describing the virus as "dhoort" (sly) and "bahurupia" (shapeshifter) in Hindi, Modi in an interaction with district magistrates (DM) and field officials also underlined concerns expressed in various quarters about the threats it poses to the youth and children.

He asked them to keep a track on it and record the spread of infection and its seriousness among them in their districts.

Modi also said that there is a need to prevent vaccine wastage, saying every dose wasted is denying someone protection shield against the disease.

He also said new challenges call for newer solutions.

In his interaction with the second batch of officers on ways to tackle the Covid-19 pandemic, the first was on Tuesday, he asked them to work to rid the rural areas of the infection and talk to villagers to guide them.

He said there is a need to ensure Covid appropriate behaviour even after the number of cases go down.

While the cases have gone down in numbers, the challenge remains as long as the infection remains even at a minor scale, he said

The prime minister praised the officials for their efforts in making the good use of existing resources to fight "the biggest disaster in 100 years".

The officials, who interacted with Modi via video-conferencing, were from Chhattisgarh, Haryana, Kerala, Maharashtra, Odisha, Puducherry, Rajasthan, Uttar Pradesh, Bengal and Andhra Pradesh.