Thread by @polinaivanovva

Russia has produced just 33 million doses of its Sputnik V vaccine so far. We spoke to people across the supply chain to find out why:

with @ykymykovna
reuters.com/business/healt…

1. Initial scale-up was hard.

The chief exec of one firm described working as if "blindfolded" at first.

"Vaccine production takes 1-1.5 months... Then, you compare output to the reference sample. If it matches, you're lucky. If it doesn't, you pour out the product you made."

His firm was gearing up to make 10 million doses a month but by late March had still not produced 1 mln. It began the process of cell growing in November.

Its new plant - a Soviet-era car factory turned into a state-of-the-art biotech facility - has yet to open officially.

2. Two different vectors.

A key challenge is the design. Unlike other vector vaccines, the first dose and booster shot use different adenovirus vectors, in order to boost effectiveness.

As another manufacturer put it, that means learning how to produce two different vaccines.

Such technical challenges have now been resolved, producers said.

The industry ministry said output was more than meeting demand. "Any local issues related to vaccine production are dealt with promptly," it said, adding it ensures "that there is enough vaccine for everyone."

3. The booster shot is harder to make, some said.

For this, Russia teamed up with AstraZeneca, whose vaccine uses a different adenovirus shot, two sources familiar with vaccine strategy said -- human trials of a mix-and-match vaccine are under way in several countries.

Another option for this is 'Sputnik Light' -- which uses just the first shot.

A third Russian pharma chief exec said he plans to seek permission for his firm to produce only this one-dose vaccine.

The fund behind Russia's global vaccine rollout said both shots were being produced and delivered on time.

Doses for export will largely be produced abroad and Russia has signed numerous major manufacturing deals with firms in India, China, South Korea and more.

It said this network planned to produce enough doses to vaccinate 800 million people in 2021, that it had demonstrated a strong commitment to honoring its international supply contracts, and stood by an offer to provide 50 mln people with doses in the EU.

4. A natural ceiling -- manufacturing plants.

There are a limited number. Some pharma firms were able to repurpose plants to produce Sputnik V. To expand further, new plants will be needed.

One firm is building a site to make 200-300mln doses p/year.

5. Staff.

"We can buy equipment, we can build plants. But in biotechnology, competent people is the most important thing. And there are not very many of them"