Prime Minister Narendra Modi on Monday took his first dose of a Covid-19 vaccine and urged people to vaccinate themselves, but the Centre’s online portal for advance registration appeared unprepared for the deluge of vaccine aspirants.

Nearly 2.5 million people on Monday registered themselves for Covid-19 vaccines, but glitches in the online registration process prevented many across India from booking appointments, a nationwide survey and healthcare sector executives have suggested.

The Union health ministry said over 128,000 people aged 60 years or older and 18,850 between 45 and 59 years with chronic health disorders had received their first doses by 7pm. About 126,000 healthcare and 152,000 frontline workers also received vaccines.

Modi through a morning tweet announced that he had taken the first dose of the vaccine.

“Took my first dose of the Covid-19 vaccine at AIIMS … I appeal to all those who are eligible to take the vaccine. Together, let us make India Covid-19 free,” he wrote.

A spot online survey, however, found that about 92 per cent of a sample of 6,845 people from more than 200 districts who tried to register in advance through the Centre’s Co-Win portal were unable to book appointments between 9.30am and 2.30pm.

The vaccination campaign that began on Monday is open to people aged 60 years or older and those between 45 and 59 years with any of 20 specified chronic health disorders.

Only 8 per cent of that sample successfully booked appointments, according to the survey by Local Circles, a community social media platform. About half of those who tried to register found themselves stuck at the OTP (one-time password) stage, 13 per cent failed to access the portal, while 29 per cent registered themselves but could not book appointments.

“These must be teething troubles, maybe because of the large numbers trying to register,” said Girdhar Gyani, executive director of the Association of Healthcare Providers of India, a body representing private hospitals and nursing homes across the country.

Some hospitals have assigned separate time slots for those with advance registrations and those wishing to opt for spot walk-in registrations.

The Centre said about 644,000 beneficiaries on Monday booked their appointments.

Despite the registration glitches, many private hospitals reported smooth vaccinations and patience among recipients.

“There was enthusiasm among recipients — when the online portal didn’t work, people just waited — we didn’t see any dissatisfaction. They just waited with cups of coffee,” Devinder Rana, chair of the Sir Ganga Ram Hospital, New Delhi, where 96 recipients had registered in advance and 88 were walk-ins.

The campaign seeks to eventually immunise everyone 50 years or older and those below 50 with chronic health disorders, an estimated 270 million people.

India’s Covid-19 epidemic has been growing over the past two weeks, driven largely by a sharp increase in new cases in Maharashtra, Punjab and Madhya Pradesh.

Infectious disease sleuths and genomic scientists are scrambling to determine whether the growing counts in these states are due to complacency with personal protection measures, poor public health responses or unusual fast-spreading coronavirus variants.