GUWAHATI, INDIA (REUTERS) - When doctors in a flood-ravaged Indian state urgently sought plasma of a particular blood type for a Covid-19 patient this month, health officials sent a boat for a marooned donor who had recovered from the disease weeks ago.

With coronavirus cases surging in the north-eastern state of Assam and critical medicines running low, local authorities are rolling out the red carpet for now-cured patients - all for their blood plasma, believed to be rich in virus antibody, although research on its efficacy has not been conclusive.

Assam says that symptomatic patients who donate plasma four weeks after recovery will get preference in government jobs and housing.

For example, a donor may get extra marks if he or she is tied in any test or interview for a job.

It is also offering to cover travel and other expenses for donors from outside the state, and has been making its front-line workers scour the state - sometimes wading through flood waters - to bring willing participants to plasma donation centres.

The success of the overall effort is crucial for Assam, one of India's poorest states that is short of remdesivir and tocilizumab to treat severe Covid-19 patients.

Delhi and Odisha states are also courting plasma donors as India's total infections have leaped to 1.4 million with nearly 33,000 deaths.

"Recently, we wanted O-group plasma for a patient, a doctor," Assam Health Minister Himanta Biswa Sarma told Reuters in an interview.

"When we learned that a person was willing to donate, people went to his house by boat, brought him to the hospital and got the donation done."

He declined to identify the donor but said the recipient was doing well.

Plasma from a previously infected person can be used to treat up to two moderately ill patients, Mr Sarma said.

Without timely treatment, such patients' condition can potentially worsen, further straining the limited pool for medicines.

"We have seen that if you give plasma between moderate and critical stages, the results are very, very good," he said.

GREY MARKET

Assam, where floods have so far killed around 100 people and affected roughly three million, is predicting coronavirus infections will peak in mid-September.

It has so far reported more than 32,000 cases with 79 deaths.

Its push for plasma comes as India, the world's biggest suppliers of generic drugs, scrambles to end a local shortage of remdesivir and tocilizumab.

Although US drugmaker Gilead Sciences has authorised six companies operating in India to make and sell generic versions of remdesivir, only three of them have so far been able to start making supplies available.

Sarma said that until recently, Assam was receiving only 12-16 remdesivir vials a day, compared with a demand for at least 100.

But the situation eased when Assam got 400 vials from a local company some days ago, he said.

"Still, people are not doing enough production and obviously a grey market has emerged as a result," Mr Sarma said.

To reduce India's dependence on export in the medical sector, Minister for Chemicals and Fertilisers Sadananda Gowda said he has launched schemes to boost manufacturing in the bulk drugs and medical device industries on Monday.

"The objective is to make India self-reliant in production of 53 critical APIs (active pharmaceutical ingredients) or key starting materials (KSMs), and in production of medical devices, for which India is crucially dependent upon imports," Mr Gowda tweeted.