India began inoculating health workers Saturday in what is probably the world’s biggest COVID-19 vaccination campaign, joining the ranks of wealthier nations where the campaign is already well underway.

India is home to the world’s biggest vaccine manufacturers and contains among the largest immunization programs. But there’s not any playbook for the enormity of the current challenge.

Indian authorities aspire to provide photographs to 300 million people, roughly the population of their U.S and several times more than its current program that targets 26 million infants. The recipients include 30 million doctors, nurses and other front-line workers, to be followed by 270 million people that are either more than 50 years old or have illnesses that make them vulnerable to COVID-19.

For workers who have pulled India’s battered health care system through the pandemic, the shots provided confidence that lifestyle can start returning to normal.

The initial dose was administered into a sanitation worker at the All Indian Institute of Medical Sciences in the capital. New Delhi, after Prime Minister Narendra Modi kickstarted the effort with a nationwide televised speech.

“We are launching the world’s biggest vaccination force and it shows the world our ability,” Modi said. He implored citizens to keep up their guard and not to believe any”rumors concerning the safety of the vaccines.”

It was not apparent whether Modi, 70, had shot the vaccine himself like other world leaders as an instance of the shooter’s safety. His government has said politicians won’t be considered priority groups in the first phase of the rollout.

Health officials haven’t specified what percentage of India’s nearly 1.4 billion people will be targeted at the campaign. But experts say it will almost certainly be the largest such drive globally.

The sheer scale has its own challenges. For instance, India intends to rely heavily on an electronic platform to track the shipment and delivery of vaccines. But public health experts point out that the web remains patchy in massive parts of the nation, with a few remote villages entirely unconnected.

Around 100 people were to be vaccinated in each of the 3,006 centers throughout the nation on the first day, the Health Ministry said.

News cameras captured the shots across hundreds of hospitals, underscoring the pent-up hopes which vaccination was the very first step in getting past the pandemic that has devastated the lives of so many Indians and occupying the nation’s market.

Cargo airplanes flew 16.5 million photographs to different Indian cities last week.

But doubts over the efficacy of the homegrown vaccine is creating barriers for the ambitious plan.

Health experts fear that the regulatory shortcut taken to approve the Bharat Biotech vaccine without even waiting for concrete data that would reveal its efficacy in preventing illness from the coronavirus could amplify vaccine hesitancy. A minumum of one state health minister has compared its use.

In New Delhi, doctors at Ram Manohar Lohia Hospital, among the largest in the city, demanded that they are treated the AstraZeneca vaccine instead of the one developed by Bharat Biotech. A physicians union at the hospital said a lot of its members were “bit nervous about the absence of complete trial” for its homegrown vaccine.

“Right nowwe don’t have the choice to chose between the vaccines,” said Dr. Nirmalaya Mohapatra, vice president of the hospital Resident Physicians Association.

India’s Health Ministry has bristled at the criticism and claims that the vaccines are safe, however, asserts that health workers will not have any choice in deciding which vaccine they’ll get themselves.

According to Dr. S.P. Kalantri, the manager of a rural hospital in Maharashtra, India’s worst-hit state, such an approach was worrying because he explained the regulatory approval was not endorsed by science.

“In a rush to be populist, the government (is) taking decisions that may not be in the best interest of the common person,” Kalantri explained.

Against the background of the rising global COVID-19 death toll — it topped two million on Friday — that the clock is ticking to vaccinate as many individuals as you can. But the campaign was uneven.

In wealthy countries such as the USA, Britain, Israel, Canada and Germany, countless taxpayers have been given some measure of security with a minumum of one dose of vaccines developed with revolutionary speed and quickly authorized for use.

But elsewhere, immunization drives have hardly gotten off the floor. Many experts are predicting another year of hardship and loss in areas like Iran, India, Mexico and Brazil, which accounts for about a quarter of the planet’s COVID-19 deaths.

Over 35 million doses of different COVID-19 vaccines have been administered around the Earth, according to the University of Oxford.

While the majority of the COVID-19 vaccine doses have been snapped up by wealthy countries, COVAX, a U.N.-backed endeavor to provide shots to developing parts of the world, has found itself short of vaccines, cash and logistical help.

As a result, the World Health Organization’s chief scientist, Dr. Soumya Swaminathan, cautioned this week that it is highly improbable that herd resistance — which would demand at least 70 percent of the world to be vaccinated — will likely be achieved this season.

“Even if it occurs in a few pockets, in a few countries, it is not likely to protect people around the world,” she explained.