India has dramatically increased COVID-19 vaccination rates in its vast rural hinterland, where about 65 percent of the country’s nearly 1.4 billion people live.

But supply constraints remain for the world’s largest maker of vaccines and experts say it is unlikely India will reach its target of vaccinating all adults by the end of the year.

India opened vaccine shots for all adults in May. But the campaign faltered in villages due to vaccine hesitancy and misinformation.

That started changing in mid-July and of the nearly 120 million shots administered in the past three weeks, about 70 percent were in India’s villages – up from about half in the initial weeks of May.

Although the increased vaccine acceptance in rural areas is promising, the pandemic is far from done in India. After weeks of steady decline, the 46,000 new infections reported on Saturday were the most in almost two months.

Only about 11 percent of India’s vast population is fully vaccinated. Half of all adults and about 35 percent of the total population have received at least one shot. This has left large swaths of people still susceptible to the virus.

Meanwhile, several nations, including the United States and Israel, are offering or plan to offer booster shots to people, deepening global vaccine inequity.

India was expected to be a pivotal producer of shots to immunise the world but stopped exports after an explosion of infections.

While India had expected to get 1.35 billion shots in the final five months of 2021 to resolve its supply constraints, the question of whether Indian vaccine makers can scale up production to meet India’s needs will have global implications.

“Currently in India, there is more demand than available supply … the supply of vaccines currently in use is lower than the projections made a few months ago. So both of these situations are putting constraints on availability of vaccines in the country,” said Dr Chandrakant Lahariya, a vaccine policy expert.

India is no stranger to mass immunisations, but this is the first time that shots are being given at this scale, and to adults. Officials have blended strategies that were successful in the past with newer, more localised innovations.

Public health experts say the uptick in rural vaccinations is important because healthcare systems in villages are fragile. The deadly surge of infections that overwhelmed hospitals earlier this year ripped through rural India and thousands died.

Moreover, migrants from villages move to cities for work and until everyone is vaccinated, outbreaks and even the possibility of a dangerous new variant cannot be discounted, said Lahariya.

India has the infrastructure to vaccinate up to 10 million people daily, but is averaging between five and six million, he said.