India’s ambitious drive to vaccinate millions of healthcare workers against Covid-19 has been hit by an IT glitch and deepening suspicion of a homegrown vaccine just days after the campaign was launched.

The country vaccinated 148,266 people on Monday, far short of the 300,000 daily shots that were expected to be given in the first week of the drive.

Just 454,059 Indians have received a first vaccine dose since the campaign kicked off on Saturday, far below the rate needed to meet New Delhi’s target of inoculating 300m frontline healthcare workers and elderly Indians by the end of August.

Scientists and public health experts said there were doubts about the efficacy of Covaxin, Bharat Biotech’s indigenously developed vaccine.

Local regulators approved the use of Covaxin in “a clinical trial mode” without completing phase 3 studies.

But Narendra Modi’s government appeared determined to launch an “Indian-developed” vaccine simultaneously with Covishield, a locally produced version of the Oxford/AstraZeneca jab, which has already been approved for emergency use in the UK, Australia and elsewhere.

Critics said the government’s “vaccine nationalism” had undermined public confidence, as had the regulator’s refusal to answer questions about its approval of Covaxin.

“Healthcare workers should be getting a vaccine that is proven to be effective — not a vaccine that some people believe will be effective. That is the real issue,” said Shahid Jameel, director of Ashoka University’s Trivedi School of Biosciences. “This is a political decision, whatever they may say.”

New Delhi is not offering recipients a choice of vaccine, providing instead different jabs at different sites. At some hospitals, frontline health workers have refused to take Covaxin, demanding access to Covishield instead.

In New Delhi on Monday, fewer than half of the 8,100 healthcare workers designated for vaccination turned up for their jabs.

“This nationalism about vaccines is causing a lot of confusion,” said Dr Jameel. “Healthcare workers, who are first in line to receive the vaccine, and who understand the process a little better than others, have become very wary.”

According to a poll this month, almost 70 per cent of Indians are reluctant to be inoculated, but public hesitancy was not the only vaccination hiccup. CoWIN the campaign’s automated vaccination app, was supposed to notify those tapped for a shot when and where to turn up, then authenticate their identities before receiving their jabs.

But officials admit that not all those earmarked for a jab had received their text message notification, and that the system was struggling to operate in areas with poor internet connectivity.

The platform also failed to anticipate that some people selected for vaccination may not turn up, and had no provision to allow others to be inoculated instead. Officials said they hoped to introduce more flexibility in the system by next week.

“The pace has not been that good — let’s hope it picks up next week,” conceded an official, who requested anonymity.

Randeep Guleria, the director of All India Institute of Medical Sciences and a member of the government's Covid-19 task force, blamed the slow vaccine take-up on misinformation.

“A lot of people have had to work on reassuring others that there have been no shortcuts,” Dr Guleria told the Hindustan Times

India has the second-highest number of coronavirus cases in the world but the number of infections has dropped precipitously recently. On Monday, fewer than 10,000 new cases were reported.