The prevailing Covid-19 situation in some districts is "increasingly severe", and the entire country is potentially at risk, said Dr VK Paul, member Niti Aayog (Health), on Tuesday.
Dr Paul heads the National Expert Group on Vaccine Administration for Covid-19 and is a core member of the central government's Covid-19 response team.
Addressing a press conference on Tuesday, Dr VK Paul said, "The Covid-19 virus is very active. It can penetrate our defences and it is a concern that we should be mindful of."
Speaking about the significance of masks as a protective measure even though vaccination drive has started, he said despite vaccines, people will have to wear masks for a "long time" to protect themselves.
"We can have all the vaccines in the world but we will, for a long time, need masks to protect us," Dr Paul said.
"We are facing an increasingly severe and intensive situation in some districts but the whole country is potentially at risk. All efforts to contain the virus and save lives should be taken," he added.
Studies on the virus causing Covid-19 have shown that wearing a mask helps stop infected people from spreading the disease to others. Scientific evidence also suggests that masks may offer some protection for the people wearing them.
The virus spreads from droplets people spray when they cough, sneeze or talk. Surgical or cloth face masks can block most of those particles from spreading.
While some droplets may still spread out, wearing a mask could reduce the amount, providing a benefit to others.
Private sector needs to come forward: Dr VK Paul
Commenting on the scale and speed of Covid-19 vaccination drive in the country, Dr VK Paul said of the private sector needs to come forward and participate in the vaccination drive.
"We were told there are 20,000 private vaccination centres in the country. But less than 6,000 vaccination centres are being run by the private sector in India. We request the private sector to make the remaining vaccination centres functional and increase their number," Dr VK Paul said.
Vaccines available to all above 45 from April 1
Meanwhile, Union Health Secretary Rajesh Bhushan said from April 1, all people above the age of 45 years will be eligible for Covid-19 vaccination.
"Advance appointment can be booked through http://cowin.gov.in. If you don't want to do this, you can go to your nearest vaccination centre after 3 pm and go for on-site registration," Bhushan said.
He added that those who opt for on-site registration should carry an identity document to their nearest vaccination centre after 3 pm.
"Usually it is Aadhaar Card and Voted ID. But you can also produce bank passbook, passport, ration card," he said.
The central government had earlier this month announced that all people above 45 years would be eligible for vaccination from April 1.
Until now, only senior citizens above 60 years and people with comorbidities above 45 years were eligible for vaccination.